@conference {3678,
	title = {Induction of delayed-type hypersensitivity reactions to Candida albicans in pasture-based dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {233-238},
	address = {Napier},
	abstract = {Delayed-type hypersensitivity (DTH) reactions to Candida albicans are regularly used as an in-vivo indicator of cell-mediated immune function in cattle. Prior immunisation against C. albicans ensures a large clone of antigen-specific memory T cells, resulting in larger DTH responses and positive responses from a greater proportion of cows. Previous experimental results indicate that natural exposure to C. albicans is minimal in cows housed indoors and does not interfere with the interpretation of DTH responses to C. albicans in pre-immunised cows. However, housed cows may have different natural exposure to C. albicans than cows grazing fresh pasture outdoors. To determine if C. albicans is an appropriate antigen for inducing measurable DTH responses in pasture-based cows, DTH responses to C. albicans were assessed in ten cows pre- immunised with C. albicans and ten unimmunised control cows. A greater proportion of immunised versus unimmunised cows mounted a positive DTH response (90\% vs. 70\%), and responses were larger (P<0.01) and more variable (P<0.05) in immunised cows. Maximum relative double skinfold thickness increased 4.3 mm ({\textpm}0.7; SEM) and 1.4mm ({\textpm}0.2) in immunised and unimmunised cows, respectively. The results of this experiment suggest that pasture-based dairy cows in New Zealand have a low background exposure to C. albicans and pre-immunisation with C. albicans is required when using DTH responses as an indicator of cell-mediated immune function in pasture-based cows.},
	issn = {1176-5283},
	author = {McGowan JE and Hine BC and Mallard BA and Verkerk GA}
}
@conference {60941,
	title = {Identification of potential impacts of New Zealand dairy housing systems on dairy cow welfare : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {54-56},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Although housing of dairy cows is not acommon management practice in New Zealand, it is becoming increasingly used for a variety of reasons. Potential benefits from dairy housing have been identified as pasture protection, effluent management, cow health and welfare, supplementary feed management and increased production (Dexcel, 2005). Laven and Holmes (2008) further explored potential health and welfare issues associated with increased use of housing for dairy cows in New Zealand. However, there is to date very little empirical research... Continued},
	issn = {1176-5283},
	author = {Arnold NA and Verkerk GA and Gregory R and Matthews LR}
}
@conference {41553,
	title = {Animal welfare in large dairy herds: a survey of current practices},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {127-131},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {To gain insight into the farm practices and animal welfare issues on large dairy herds, we conducted a postal survey (n = 132). The questionnaire covered four areas: demographics, stand-off practices, management during extreme weather, and races. Respondents managed 910 {\textpm} 466 (mean {\textpm} SD) milking cows during the 2003 season. When asked to identify the most important animal welfare problem on their farm, 73\% of the respondents named one of the following: lameness, disease, or nutrition/growth. Fifty-one percent of respondents used some form of stand-off area during periods of inclement weather. There are several management practices used with stand-off areas that are relevant to animal welfare including: provision of feed, shelter, space allowance, and surface type. During extreme winter and summer weather, a range of practices was used to manage cows, including changes in grazing patterns. For example, 61\% of respondents used paddocks closer to the milking shed and 40\% used sprinklers at the shed during hot weather. Finally, on average, cows walked 1.9 {\textpm} 0.8 km to the milking shed, and walking distance increased with the number of cows/farm. Farmers demonstrated awareness of animal welfare issues and implemented management practices that likely improve the well-being of their stock.
KEYWORDS: animal welfare; dairy cattle; herd size; management practices. },
	issn = {1176-5283},
	author = {Tucker CB and Verkerk GA and Small BH and Tarbotton IS and Webster JR}
}
@conference {41486,
	title = {Use of breeding values for live weight to calculate individual live weight targets for dairy heifers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {118-121},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Replacement heifers need to reach specific target live weights (LW) to ensure they calve as two year olds, and subsequently achieve high milk yields and good fertility. Currently, different LW targets are recommended for heifers based on their expected mature LW according to appearance or breed. However, the mature LW is difficult to estimate without knowledge of the animals. genetic potential for LW. The objective of this paper is to develop and validate a growth model which uses estimated breeding values for LW (EBV LW) of individual heifers of any breed to calculate target LW from birth to maturity. Predicted live weights are presented for a range of four EBV LW, from {\textendash}40 to 100 kg. These values were very similar to other published target values. Data from the Dexcel Holstein Friesian Strain Trial was used to validate the model with respect to LW and age at puberty. For LW at puberty the predicted values were significantly correlated (P<0.05), but were marginally higher (3-5\%) than the actual values. A report can be formulated to enable farmers to identify individual heifers which are below (or above) their target LW at any date },
	issn = {1176-5283},
	author = {Bryant JR and Holmes CW and Lopez-Villalobos N and McNaughton LR and Brookes IM and Verkerk GA and Pryce JE}
}
@conference {41399,
	title = {Metabolic responses to glucose challenge in New Zealand and overseas Holstein-Friesian dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {31-34},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {North American and Dutch Holstein-Friesian (HF) cattle have undergone genetic selection for increased milk production, however, at the same time, reproductive efficiency has decreased. Overseas HF also have greater propensity to mobilise body reserves during early lactation than New Zealand HF cows. It is possible that reproductive differences are a consequence of metabolic and endocrine differences between the strains. This trial was designed to investigate effects of genotype and diet on endocrine response to a challenge of intravenous glucose in HF cows. Twenty-five HF cows of New Zealand (NZ; n=13) and Overseas (OS; n=12) origin, were fed either pasture (Grass; n=12) or a total mixed ration (TMR; n=13) in a 2x2 factorial design. At two weeks postpartum, they were challenged with 300mg of glucose/kg live weight. Data were analysed for effects of genotype and diet. Following glucose challenge, the NZ TMR cows had higher plasma insulin concentrations than the NZ Grass, resulting in a significant interaction between diet and genotype in the area under the response curve; but the OS groups had similar patterns. Mean plasma leptin concentration was higher in NZ TMR than in NZ Grass, OS TMR or OS Grass. Plasma concentrations of glucose and IGF-I were not affected by genotype or feed regime. These results demonstrated metabolic differences between the strains and also diets. A better understanding of the genetic and nutritional basis of hormonal regulation of nutrient partitioning will be important to develop nutritional strategies to meet the requirements of lactating cows with different genotypes, and to find ways to improve reproductive efficiency. },
	issn = {1176-5283},
	author = {Chagas LM and Clark BA and Rhodes FM and Blache D and Kolver ES and Verkerk GA}
}
@conference {41410,
	title = {Postpartum anoestrous intervals and reproductive performance of three genotypes of Holstein-Friesian dairy cattle managed in a seasonal pasture-based dairy system.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {77-81},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {An extended postpartum anovulatory interval (PPAI) is the major form of infertility in New Zealand (NZ) dairy cattle. Recently, Holstein cows, originating from North American genetic strains (Overseas; OS), have been widely used in NZ. Worldwide, there is concern over an apparent decline in the fertility of Holstein-Friesian dairy cattle. This study determined whether differences existed in PPAI, BCS and parameters of reproductive performance between NZ and OS Holstein-Friesians. One hundred and forty-six records from 88 NZ animals of high genetic merit for milk production (NZH), 81 records from 48 NZ animals of low genetic merit (NZL), and 137 records from 88 OS high genetic merit animals that calved in Years 1 (all two-year-olds) and 2 (two- and three-year-olds) were included. Over both years PPAI in two-year-olds were significantly shorter in OS (20 days shorter) and NZL (12 days shorter) than in NZH animals (P<0.05). Body condition score at calving, and BCS loss from calving to four weeks postpartum were not different between strains. In Year 1 of the study significantly more NZH than NZL or OS 2-year-olds were treated for anoestrus prior to the start of mating (P=0.001). Other measures of reproductive performance did not differ significantly between strains. The differences in PPAI require further investigation. },
	issn = {1176-5283},
	author = {McNaughton LR and Verkerk GA and Parkinson TJ and MacDonald KA and Holmes CW}
}
@conference {41363,
	title = {Factors influencing inducing decision-making in dairy cows: a case study of scientists{\textquoteright} and producers{\textquoteright} views},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {257-260},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {<p>The purpose of this investigation was to identify and describe the on-farm decision-making context of dairy farmers when they decide to induce dairy cows. A social researcher facilitated the meetings between a Waikato dairy farmer and two collaborating groups, to gather and record data regarding on-farm induced parturition decision-making over a year. These sessions took place at times when decision-making would impact most on induction. Cognitive mapping was used to capture the context within which decision-making in connection with inducing dairy cows took place. The following main conclusions were made: a long term perspective of induction is required; the induction decision-maker does not have control over all the factors that influence induction but could foresee and manage several of them by appropriately using applicable records; cow condition plays a critical role; the focus farmer had a much more straightforward view than scientists of induction and viewed it on a time line; decision-making with regards to inducing cows is a continuous process and capturing it requires a systems perspective; the interactions between different factors that influence induction become more apparent and more obvious to participants when these factors were made visual through the cognitive mapping technique.</p>},
	issn = {1176-5283},
	author = {Botha CAJ and Verkerk GA}
}
@conference {41307,
	title = {Monitoring onset of puberty in three genetic strains of Holstein-Friesian dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {30-33},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Live weight and age at puberty were determined in three strains of Holstein-Friesian dairy cattle in each of two consecutive years. The strains were overseas-origin high-breeding-worth genetics (OS), New Zealand-origin high-breeding-worth genetics (NZH), and New Zealand-origin low-breeding-worth genetics (NZL), similar to the New Zealand dairy cow of the 1970s. Onset of puberty was monitored by weekly measurement of progesterone in a total of 271 heifers. Animals were considered to have attained puberty when plasma progesterone concentrations were greater than 2ng/ml in two out of three consecutive samples. Live weight at puberty differed between the strains (OS > NZH > NZL; P<0.05) but not between years. Age at puberty was affected by strain in Year 1 (OS > NZH > NZL; P<0.01), but not in Year 2. The greater live weight required to attain puberty in OS genotype animals must be recognized in target live weights for rearing of heifers. },
	issn = {1176-5283},
	author = {McNaughton LR and Morgan SR and Gore P and Verkerk GA and Holmes CW and Parkinson TJ}
}
@conference {41311,
	title = {Winter dairy grazing systems: management practices and cow comfort},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {44-48},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {During winter, it is common practice to move dairy cows to a stand-off area. This project aimed to identify off-pasture management systems on farms and compare cow comfort on a variety of stand-off surfaces. A questionnaire was distributed in several dairying regions. The most common types of stand-off surfaces were concrete, or concrete in combination with another type of system. More farmers using woodchip surfaces reported that their cows laid down than those using concrete. The major health problem identified was lameness, and the majority of farmers believed that a woodchip pad worked best. Lying behaviours of 216 pregnant, non-lactating Friesian cows, on 18 farms in Waikato and Southland were recorded. Waikato cows were stood-off on woodchip pads, concrete and farm races. In Southland, covered and uncovered sawdust pads and crops were used. Cows spent longer (P<0.05) lying per day on woodchips (11.3 hrs) than on concrete (2.4 hrs) and races (4.1 hrs). Lying times for cows on covered sawdust pads (10.2 hrs) were not different from those on uncovered pads (11.5 hrs) or crops (11.2 hrs). A properly managed woodchip surface may cause less lameness and provide better opportunities for cows to rest than concrete surfaces or races. },
	issn = {1176-5283},
	author = {Stewart M and Fisher AD and Verkerk GA and Matthews LR}
}
@conference {41278,
	title = {CowTrakker technology for improved heat detection},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {172-175},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Devices designed to detect motion (CowTrakker{\texttrademark}, Bou-Matic, USA) were attached to Holstein-Friesian cows of either NZ or overseas origin. Animals of each strain either grazed pasture or were fed a total mixed ration. Milk samples were collected twice weekly and progesterone content analysed to identify ovulation events. Cows had tail paint applied from 2 weeks after calving, and were observed twice daily at milking for oestrous activity. Recording continued until 6 weeks after the planned start of mating (PSM). Cows were artificially inseminated following a progesterone-based synchrony programme at PSM. CowTrakker{\texttrademark} data were analysed using four algorithms (T3/1, T3/3, T10/1 and T10/3), which varied according to the period of the rolling average used (3 or 10 days) and the standard deviations from that average (1 or 3). These measurements were related to behavioural observations and the occurrence of ovulation. There was a significant number of false positive events detected by the CowTrakker with all algorithms (sensitivity: 12.3, 46.9, 62.3 and 81.5\%; specificity: 67.1, 88.4, 95.4 and 99.0\%, for T3/1, T3/3, T10/1 and T10/3, respectively) as compared to behavioural observations alone (sensitivity: 71.6\%; specificity: 99.6\%). The CowTrakker{\texttrademark} was a useful heat detection aid, but must be used in conjunction with careful behavioural observations in order to interpret the high proportion of false positive events that are recorded.},
	issn = {1176-5283},
	author = {Verkerk GA and Claycomb RW and Taufa VK and Copeman P and Napper A and Kolver E}
}
@conference {41272,
	title = {Magnesium supplementation of lactating dairy cows in the summer and autumn},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {148-151},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A series of three trials were established with 188 lactating dairy cows which were supplemented daily with either 0, 10 or 20 g Magnesium (Mg) during 18 weeks from January to May. Cows in each trial were allocated to treatments randomly in a cross-over design with each treatment lasting 2 weeks. This design was replicated three times during the 18 weeks. There was no treatment effect on serum Mg or milksolids (MS) production, (0.82, 0.82 \& 0.83 mmol/l or 0.78, 0.79 \& 0.77 kg MS/cow/day for 0, 10 \& 20 g Mg, respectively; averaged across all trials) and there were no farmlet-by-treatment interactions. Based on visual assessments of pasture intakes and pasture mineral analysis, mean pasture Mg intakes during all three trials ranged from 23 to 35g Mg/cow/day (SEM 1.14). Urine Mg-creatinine ratio of 50 cows during Trial 3 indicated that the urinary Mg concentration increased linearly with increasing dietary Mg (1.38, 1.87, 2.01 for the 0, 10 and 20 g treatments, respectively; SED 0.175). Trial three results suggest that Mg surplus to requirement was being voided by the cow and that it is unlikely that even at the higher stocking rates, a milk production response to Mg supplementation will occur in the summer/early-autumn period when Mg in diet is >0.18\%. },
	issn = {1176-5283},
	author = {MacDonald KA and Penno JW and Verkerk GA and Jago J and Dow BW}
}
@conference {41244,
	title = {Monitoring adrenal activity in dairy cows under various feeding regimens using faecal glucocorticoid metabolites},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {52-55},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Adrenal activity in cattle can be measured by changes in plasma glucocorticoid concentrations. Cows treated with synthetic adrenocorticotrophic hormone (ACTH) to stimulate the adrenal cortex exhibited elevated plasma cortisol concentrations for 4-5h. Concentrations of faecal glucocorticoid metabolites (FGM) peaked between 8-9.5h after ACTH treatment, 2.5 fold higher than basal (P<0.05) and remained elevated for 13h (range, 11.1-16.1h). Faecal glucocorticoid concentrations were monitored in two strains of Holstein Friesian (HF) dairy cows farmed in New Zealand under two systems: NZ pastoral and North American concentrate-based. The overseas (OS) and New Zealand (NZ) HF were fed a pasture-based diet (Grass) or a total mixed ration (TMR) throughout lactation. Faecal samples were collected on four occasions during lactation. Faecal glucocorticoid concentrations of the cows fed Grass were consistently higher (P<0.05) than cows fed TMR. There was also a significant genotype effect; FGM concentrations of the NZ HF cows were higher than OS HF cows (P<0.05). In a separate study, no obvious trends were evident in FGM in NZ HF grazing pasture at three stocking rates (2.2, 3.2, 4.3 cows per hectare). Measuring FGM can be used to monitor acute adrenal activity in cows, but is more difficult to interpret as a measure of chronic stress. },
	issn = {1176-5283},
	author = {Morrow CJ and Kolver ES and MacDonald KA and Verkerk GA and Matthews LR}
}
@conference {41282,
	title = {Postpartum anoestrous interval and metabolic changes in heifers supplemented with pasture prepartum},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {188-191},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The aim of this study was to determine whether supplementation with pasture from 6 weeks before calving would alter the postpartum anoestrous interval (PPAI) in heifers calving with low body condition score (BCS). Metabolic hormones and metabolites were measured during the pre- and postpartum period. Forty Friesian heifers were managed during the last five months of gestation to achieve a BCS (1-10) of 4.0 (restricted; R; n=27) or 5.0 (fully fed; FF; n=13) by 6 weeks prepartum. One group with low BCS then received pasture ad libitum until calving (restricted + fully fed; R+FF; n=12). Live weight (LW) and BCS were assessed weekly. Blood samples were collected weekly from 10 weeks prepartum to 10 weeks postpartum to measure glucose, urea, non-esterified fatty acids (NEFA), betahydroxybutyrate (BOH) and cholesterol content. The patterns of metabolites measured differed between groups at different times, future work to investigate the relationship these profiles and PPAI would be of value. The percentage of cows cycling as measured by an elevated milk progesterone concentration was 69\%, 75\% and 8\% for FF, R+FF and R groups, respectively. Fully feeding heifers, with low condition score, 6 weeks before calving decreased PPAI when compared to heifers receiving restricted feeding. },
	issn = {1176-5283},
	author = {Chagas LM and Morgan SR and Gore PJS and Clark BA and Verkerk GA}
}
@conference {41284,
	title = {Relationships between, milk production, nutrition and reproduction in benchmark herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {195-198},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Inter-relationships between nutrition, milk production and reproduction in dairy cows were investigated in dairy herds with previous high reproductive performance. Ten herds were selected as {\textquoteleft}benchmark{\textquoteleft} farms from one area of the Waikato. Pasture and supplement intakes, and milk production were monitored on a herd basis. Bulk milk samples were taken weekly from calving through to the first three weeks of mating and assayed for levels of progesterone, urea nitrogen and b-hydroxybutyrate (BOH). Pre-mating oestrus, mating (AI) and pregnancy data were recorded. All data was expressed in relation to the planned date of mating (PSM) for each farm. Significant between farm differences were detected in all the reproductive parameters but there was no effect of supplement feeding. The mean proportion of cows cycling at PSM was 65.6 {\textpm} 3.3\% (range 50.5 to 81\%).The mean proportion of cows pregnant to AI at PSM + 3 weeks was 51.3 {\textpm} 2.1\% (range 43 to 61.5\%); at PSM + 6 weeks the mean was 74.5 {\textpm} 3.3\% (61 to 89.5\%); at PSM + 9 weeks it was 84.7 {\textpm} 2.2\% (74.9 to 91.6\%) and at PSM + 12 weeks it was 91.3 {\textpm} 1.2\% (85.6 to 95.4\%). Bulk milk progesterone rose linearly from a mean of 0.5 ng/ml at 8 weeks before PSM to 5.0 ng/ml at PSM and to 6.0 ng/ml three weeks later. The difference between farms at PSM ranged from (2.1 to 7.1 ng/ml). While the pattern of increase in bulk milk progesterone tended to mimic the overall pattern of oestrus activity, there was no relationship in the ranking of farms for these parameters at any time. Bulk milk BOH showed no consistent pattern over the period of measurement and levels ranged between farms in any one week from 0.01 to 0.05 mM. Bulk milk urea nitrogen concentration also showed little change on average (7.25 mM) over the pre-mating and mating periods. The significant between-farm differences in these bulk milk parameters did not appear to be related to reproductive performance. Metabolic indicators measured in bulk milk samples appear of little value for predicting reproductive performance at herd level. },
	issn = {1176-5283},
	author = {Smith JF and Verkerk GA and Clark BA and McKay BJ and Duganzich DM}
}
@conference {41213,
	title = {Comparison of selected reproductive characteristics in Overseas and New Zealand Holstein-Friesian cows grazing pasture or fed a total mixed ration},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {270-274},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Lactating overseas and NZ-derived Holstein-Friesian cows were fed either pasture or total mixed ration (NZGrass, n=14; NZ TMR, n=14; OSGrass, n=12; OS TMR, n=13). For cows ovulating before breeding began, mean postpartum anoestrous intervals (PPAI) were 39{\textpm}6, 29{\textpm}4, 27{\textpm}6 and 23{\textpm}2 d, respectively. Of 13 cows with PPAI 43d, four were NZGrass (P<0.02). Of seven with PPAI >43d, four were NZGrass (P<0.05). Growth of the first dominant follicle and corpus luteum through time, and day of emergence of the second follicle wave, measured by transrectal ultrasonography, did not differ between treatment groups. Feeding system affected mean plasma progesterone concentration at emergence of the second follicle wave and number of subordinate follicles recorded during the first follicle wave (4.5 {\textpm} 0.4 and 6.1 {\textpm} 0.5 ng/ml, P<0.02; 6.2 {\textpm} 0.6 and 4.1 {\textpm} 0.7 follicles/d, P<0.05; for grass and TMR, respectively). In summary, both genotype and feed system affected length of PPAI, while feed system influenced aspects of peripheral hormone profiles. },
	issn = {1176-5283},
	author = {Verkerk GA and Morgan S and Kolver ES}
}
@conference {41220,
	title = {Patterns of luteinising hormone release and embryo recovery following superovulation of cycling and anoestrous lactating dairy cows and in non-lactating cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {295-296},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Lactating dairy cows, either during postpartum anoestrus (LA; n=10) or returned to oestrous cyclicity (LC; n=10), and cycling non-lactating dairy cows (DC; n=10) were superovulated with follicle-stimulating hormone during a progesterone supplementation treatment, inseminated and embryos recovered non-surgically 7 days later. Blood samples were obtained during the period of oestrus to determine plasma concentrations of luteinising hormone (LH). Number of corpora lutea varied (14.6{\textpm}1.6, 8.1{\textpm}1.5, and 8.7{\textpm}1.9 for LC, LA and DC cows, respectively; P<0.02), but not the total number of all ova and embryos, or the total number of transferable embryos per cow. There were no significant differences between groups in either mean time from start of sampling to peak LH (37.0{\textpm}3.9, 34.5{\textpm}3.6 and 36.2{\textpm}4.5 hours for LC, LA and DC cows, respectively) or mean LH peak (12.5{\textpm}3.6, 16.6{\textpm}3.3 and 13.4{\textpm}4.2 ng/ml for LC, LA and DC cows, respectively).},
	issn = {1176-5283},
	author = {Verkerk GA and Taufa VK and Hooper R}
}
@conference {41148,
	title = {Prediction of post-partum anovulatory interval in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {15-18},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Changes in a range of metabolites and body condition parameters in lactating cows were measured during early lactation to determine if any key indicators or combination of key indicators could be used as a predictor of length of post-partum anovulatory interval (PPAI). Fifty-three cows in a range of body condition scores were involved in the trial which ran from calving to 10 weeks post-calving. Plasma non-esterified fatty acids (NEFA) and serum cholesterol, glucose, betahyroxybutyrate (BOH) and urea content were measured in weekly samples. Live weight and body condition score (BCS) were measured weekly.Cows were categorised into four groups. Three groups were based on the post-partum anovulatory interval (PPAI). PPAI was defined as the interval between calving and the first evidence of oestrus behaviour. The fourth group contained all the two-year-old cows only. There was a calving interval of 31 days from the first to the last cow to calve. The nadir for live weight for all groups occurred one week after calving. Animals with a shorter PPAI had higher live weights on all occasions, with live weight at week 5 having the strongest association with length of PPAI (P<0.001). Mean BCS was higher for animals with a PPAI<60 days. Plasma urea concentrations were associated with PPAI at weeks 3 and 4 (P<0.01). NEFA and glucose were correlated with PPAI at weeks 3 and 4 only, respectively. There was no association between cholesterol or BOH with PPAI. These results demonstrate that the selected variables do not contribute greatly to prediction of PPAI. Those measures which give the closest association with PPAI are live weight, BCS and age. },
	issn = {1176-5283},
	author = {Clark BA and Chagas LM and Gore PM and Dow B and Verkerk GA}
}
@conference {41201,
	title = {Urinary cortisol: An indicator of stress in dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {218-221},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The measurement of immunoreactive urinary corticosteroids was validated as a method of monitoring adrenocortical activity in lactating dairy cows. The physiological relevance of the technique was validated by demonstrating that (i) injection of ACTH led to a significant increase in plasma and urinary corticosteroid concentrations, and (ii) the translocation of cows from pasture to a barn facility resulted in a 1.1- to 2.5-fold increase in urinary cortisol concentrations. Plasma cortisol concentrations exhibited a 15- to 33-fold increase above basal concentrations 30 mins after ACTH administration (2.98{\textpm}0.35 vs 63.7{\textpm}3.9 ng/ml plasma; mean{\textpm}SEM; P<0.01). Monitoring urinary corticosteroid concentrations is a valid tool for studying and evaluating adrenal activity and acute stress in cattle. },
	issn = {1176-5283},
	author = {Morrow CJ and Kolver ES and Verkerk GA and Matthews LR}
}
@conference {41111,
	title = {Angus selection-herd reproductive data: A genetic model for dairy cattle?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {169-172},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A selection experiment with Angus cattle, established in 1984/85, has achieved a difference in age at puberty in heifers of 70 + 6 days (17\%) between an {\textquoteleft}Age Plus{\textquoteleft} (i.e. high age) selection line and an {\textquoteleft}Age Minus{\textquoteleft} line. Currently three heifer calf crops (born in 1993-95) are being retained until 5.5 years of age, so that pregnancy rates in 5 mating seasons (and calving data in 4 seasons) on unculled females can be recorded. Genetic correlations between pubertal traits (from either sex) and heifer or cow reproductive traits have been calculated. Similar estimates were also derived from a pilot beef-cattle trial in 1980-85 using paternal half-sib data (230 sire groups), but no selection. The objective of this paper is to evaluate the merits of selecting on pubertal traits to improve reproduction, and to assess the possibilities of this type of selection in dairy cows. Correlated responses in the {\textquoteleft}Age Minus{\textquoteleft} herd, relative to {\textquoteleft}Age Plus{\textquoteleft}, include earlier pubertal development in half-brothers (+1.6 cm (5.2\%) in scrotal circumference (SC) at 8, 10 and 12 months of age, P<0.001), an earlier mean calving date in cows by 3 days following an unchanged start-of-mating date, a 3-day reduced postpartum anoestrous interval (PPAI, adjusted for the earlier calving date), and a higher mean pregnancy rate (+4.7\%, based on 1083 matings) in cows 2 years of age or more (P<0.05). All the genetic correlations between age at puberty in heifers and cow reproductive traits in our two studies so far have favourable signs (e.g. negative between age at puberty and pregnancy rate, or positive between age at puberty and PPAI), so that selecting heifers for earlier pubertal age would be consistent with increasing cow reproduction. Because selecting heifers for puberty is not very practical, selecting bulls could be more realistic. All the genetic correlation estimates between SC and cow reproductive traits in our two studies so far also have favourable signs. Additionally, genetic correlations between SC in bulls and age at puberty in heifers are negative (-0.21 {\textpm} 0.09 and -0.19 {\textpm} 0.20, respectively in the two trials cited above), so that bull selection for higher SC would reduce age at puberty in heifers and improve cow reproduction. Thus direct selection for precocious puberty in our Angus herd (predominantly by bull selection) has led to more fertile beef cows. It is suggested that the genetic correlations observed could be an initial model for dairy cattle, showing how selection-index traits on dairy animals at puberty could be used to correct for the inferior reproductive genes of some dairy cows. },
	issn = {1176-5283},
	author = {Morris CA and Verkerk GA and Wilson JA}
}
@conference {41121,
	title = {Can Beta-hydroxybutyrate levels predict postpartum anoestrous interval of dairy cows?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {205-207},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Concentrations of  b-hydroxybutyrate in plasma (pBOH) and milk (mBOH) were measured post-partum (pp). Mean pBOH
levels were highest in Weeks 3\&4 pp (1.1 {\textpm} 0.1 mmol/L). Cows were grouped for length of post-partum anoestrous interval (PPAI) for the statistical analyses. Of those cows which required hormonal treatment because they were anoestrous at the planned start of mating, 77\% had pBOH >1 mmol/L during Weeks 1\&2 pp, compared to 52\% of other cows (P < 0.1). Levels of pBOH alone could not predict the length of the PPAI (r2  = 2\%). Logistic regression analyses confirmed age, calving live-weight and calving condition score as risk factors for prolonged PPAI. When these factors were considered with pBOH at Weeks 5\&6 pp, a predictive relationship was found (P < 0.05). Levels of mBOH and pBOH were related (r2  = 0.68; P < 0.001).  These results support negative energy balance in early lactation as a risk factor for prolonged PPAI, along with age and live-weight and body condition score at calving.},
	issn = {1176-5283},
	author = {Verkerk GA and Guiney JC}
}
@conference {41118,
	title = {The effects of stressors on lymphocyte populations and function in lactating dairy cows.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {195-197},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Increased stress in animals can lower immune system function and hence decrease resistance to disease. The objectives of the study were to determine the effects of two stressors on lymphocyte function in lactating dairy cows. Jersey cows were allocated to four, 7-day treatments in a 2 x 2 factorial plan. The factors were level of feeding (4\% bodyweight vs 3\% bodyweight) and lying time (free choice lying vs prevention of lying from 1500 to 0645 h daily). Blood samples collected during the pre-treatment and treatment periods were analysed for in vitro lymphocyte proliferative response and sub-populations. Lymphocyte proliferative response was not affected by feed level or lying time. Only minor changes occurred in lymphocyte sub-populations. Within the fully-fed cows, lying deprivation resulted in a greater proportion of CD8 (suppressor) cells. These data indicate that lymphocyte function in lactating cows may not be compromised by medium term restrictions in feeding and lying, and that any stress-induced decreases in cell-mediated immunity which occur in practice, are the result of more severe, or prolonged, conditions. },
	issn = {1176-5283},
	author = {Fisher AD and Verkerk GA and Stevenson RA and Wesselink E and Morrow CJ and Matthews LR}
}
@conference {41117,
	title = {The effects of stressors on milk composition in dairy cows.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {192-194},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The effects of two stressors (level of feeding: 4\% bodyweight, FI, and 3\% bodyweight, RI; and altered lying time: free choice, LF, and prevention of lying from 1500 to 0645 h daily, LD) allocated in a 2x2 factorial design on milk yield and composition of Jersey cows (n=32) were studied. Stressors were applied for 7 days following an 8-day pre-treatment period. Composite milk samples were collected at milkings on days 2-3 of pre-treatment and during the last 4 days of treatment. Fat\%, milk weight (am, pm and total daily) and mean daily yields of fat, casein, lactose and total milksolids were not affected by treatment. Protein\%, protein yield and casein\% were lower with RI (protein\%: 3.66 and 3.53, sem=0.02, P<0.01; protein yield: 0.54 and 0.50 kg, sem=0.01, P=0.05; casein\%: 2.84 and 2.77, sem=0.02, P<0.05 for FI and RI, respectively). There were no significant interactions between treatments. Protein content of milk was reduced by medium-term feed restriction, but lying deprivation had minimal effects. },
	issn = {1176-5283},
	author = {Verkerk GA and Fisher AD and Morrow CJ and Matthews LR}
}
@conference {41113,
	title = {Validation of body condition scoring by using ultrasound measurements of subcutaneous fat.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {177-179},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Visual assessment of body condition score (BCS) is used to aid individual cow and herd management, but the assessment is subjective and does not estimate actual body tissue reserves. Ultrasound (US) measurements of external fat reserves may be more objective. To quantify fat reserves at differing BCS{\textquoteleft}s, fat depth was measured by US on 87 mixed aged Friesian dairy cows on 6 occasions during a year. The US measurements were made at the 12th rib (RIB) and mid-way between the hip and pin bones (HIP). Animals were weighed (LW) and their BCS assessed visually at the same time. Mean BCS was greatest in early summer at 4.5 and lowest in late summer at 3.6. Mean RIB varied from 2.2 mm in mid spring to 3.6 mm in early winter, while mean HIP varied from 1.6 mm in early summer to 4.2 mm in early winter. Changes in BCS and LW were positively correlated. Age and growth in 2 year old animals did not appear to affect this relationship. BCS was positively correlated to both RIB and HIP fat depth. The correlation coefficient varied with time, being smallest in late summer (r = 0.37 \& 0.26 for RIB \& HIP respectively) and greatest in late lactation (r = 0.69 \& 0.82 for RIB \& HIP respectively). The ability of RIB \& HIP measurements to predict BCS was low when BCS was <4.5, but predictability increased as fat depth and body condition increased. Cows at lower scores may deposit or deplete fat internally while having few external fat deposits. Because large changes in liveweight (LW) occurred without changes in BCS, or US, it is possible that fat deposits are internal or intramuscular rather than subcutaneous, and therefore not detectable from external inspection. Since most BCS values are <4.5 for lactating cows, the value of ultrasound to assess fat depots in lactating dairy cows is limited; however it may be of some value with cows of BCS >4.5. },
	issn = {1176-5283},
	author = {MacDonald KA and Verkerk GA and Penno JW}
}
@conference {40994,
	title = {Effects of oestradiol benzoate by injection at CIDR insertion for the treatment of postpartum anovulatory anoestrus in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {82-84},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The effect of an intramuscular (im) injection of oestradiol benzoate (ODB) at insertion of an intravaginal progesterone-releasing device (CIDRTM, InterAg, NZ) during hormonal treatment for postpartum anoestrum in dairy cattle was investigated. Inclusion of injected ODB at CIDRTM insertion in synchronisation programmes for cycling cows can increase fertility, possibly by initiating an emergence of a new ovarian follicle wave with resultant improved oocyte competence. A total of 882 cows, of mixed age and breed from 18 herds, were examined and diagnosed as anoestrous during the week preceding each herd{\textquoteright}s planned start of mating. Cows were allocated randomly as controls or to receive 0.5 or 1 mg ODB (Oestradiol Benzoate Inj., Intervet, Netherlands) by im injection at CIDRTM insertion. The device was removed after 7 days, and any cow which was not observed in spontaneous oestrus within 48 h received 1 mg ODB im (CIDIROLTM Injection, InterAg, NZ). Cows with an observed heat within 12 days of CIDRTM removal were defined as responders, and returns to service in the subsequent 30 days were recorded. There were no significant differences between the control, 0.5 and 1 mg ODB treatments for either the proportion responding (89.5\%, 89.4\% and 90.9\%, respectively) or returning (52.3\%, 50.3\% and 55.4\%, respectively); however the proportions of cows observed in spontaneous oestrus varied by treatment (P<0.01; 28.5\%, 22.9\% and 17.2\% for control, 0.5 and 1 mg ODB treatments, respectively). Conception rates were not significantly affected by treatment (35.9\%, 42.5\% and 43.2\% for control, 0.5 and 1 mg ODB treatments, respectively). Of cows which did not become pregnant to the induced oestrus, 21.7\%, 20.7\% and 29.9\% for control, 0.5 and 1 mg ODB treatments respectively, returned to service with an interval of more than 24 days. These observations suggest that an injection of ODB at CIDRTM insertion may alter follicle wave patterns in cows with PPA, but that this may not result in increased conception rate, and might be detrimental to ovarian activity in a proportion of cows. },
	issn = {1176-5283},
	author = {Verkerk GA and Taufa VK and Morgan S and Clark BA and Macmillan KL}
}
@conference {40999,
	title = {Milk progesterone concentrations at selected times following oestrus and insemination in relation to the success of pregnancy},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {95-97},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Positive relationships between concentrations of progesterone in milk and subsequent pregnancy rates suggest that measurement of milk progesterone concentration at selected times following insemination may facilitate identification of cows for strategic progesterone supplementation to enhance the probability of pregnancy. This study investigated some factors associated with variation in milk progesterone concentration. Following a standard oestrus synchronisation treatment with CIDR-BTM devices (InterAg, NZ), cloprostenol (Estroplan injection, Parnell Laboratories NZ Ltd, NZ) and oestradiol benzoate (CIDIROL Injection, InterAg, NZ) every cow artificially inseminated (AI) at 72 h after CIDR-BTM withdrawal (Day 0) was enrolled in the trial. Milk samples (fore-milk: Herd 1, n = 153, Holstein-Friesian; HF; composite: Herd 2, n = 50 HF and 76 Jersey; J) were taken 4, 8 and 22 days after AI to measure milk progesterone concentration. Pregnancy to the insemination was confirmed by rectal palpation 60-70 days later. Lower milk progesterone concentrations were found in fore-milk (Herd 1) than composite samples (Herd 2), but followed a similar pattern of change throughout Days 4, 8 and 22. Neither return to service, nor pregnancy status was associated with altered milk progesterone concentration on Days 4 or 8, but levels on Day 22 were higher (P<0.001) in pregnant cows. Mean milk progesterone concentrations were higher (P<0.001) in J than HF in Herd 2 on Day 8. Absolute milk progesterone concentration on Day 4 or 8 following AI did not predict the probability of pregnancy establishment, but the difference between milk progesterone concentration in the two samples was of predictive value on a herd, but not an individual cow, basis. Milk collection methods and breed effects need to be considered when developing milk progesterone concentration as a predictor of pregnancy establishment. Although the non-parametric analyses showed that non-pregnant animals tended to have lower milk progesterone concentration, the requirement for analysis of at least two samples will limit its use as a practical means to identify the subset of cows for which strategic progesterone supplementation might be considered. },
	issn = {1176-5283},
	author = {Verkerk GA and Macmillan KL}
}
@conference {40940,
	title = {Induction of Parturition in Dairy Cows - A Survey from spring 1996 in the Waikato region.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {231-233},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Data were gathered relating to the practice of induction of premature parturition from farms in the central Waikato during spring 1996. A standard two-injection glucocorticoid treatment regime was employed. The reproductive tract of each cow receiving this treatment was examined 3 - 5 days post partum. Additional information relating to cow management was collected by interviewing participating herd-owners. Preliminary data relating to subsequent reproductive performance of a subset of the cows are also presented. Accurate data were obtained for a total of 691 cows on 31 dairy farms. The mean induction rate was 10\% (range 2 - 24\%) of the cows in each herd. The distribution of the ages of induced cows was skewed, with 25\% of cows being 3 yr old. Of the 35\% of cows which calved to a single injection of glucocorticoid, 76\% were within 30 days of full term based on expected calving dates. Inadequate progress in udder development following the first injection was seen in 11\% of cows, of which 78\% were more than 30 days premature. Only 56\% of cows completed the routine two-injection regime. Dystocia requiring at least moderate intervention occurred in 15 cows (2\%). There were no cows with retained foetal membranes (RFM) on 33\% of farms, but the overall incidence of RFM in cows receiving routine induction was 14\%. No intervention was required for 43\% of these, which resolved spontaneously within 48 h of calving. Milk fever was the complication most frequently reported (overall incidence 2.8\%) and contributed to 3 of the 6 reported deaths. Preliminary data from 11 farms indicated that 7\% of cows were not presented for re-breeding. Only 12\% required treatment for anoestrum. The mean calving to 1st service interval was 64 {\textpm} 2 days, and 53\% had appeared to hold to 1st service. },
	issn = {1176-5283},
	author = {Verkerk GA and Goble G and McDougall S and Woods M and Clark B and Macmillan KL}
}
@conference {40823,
	title = {An attempt to create an {\textquoteright}anoestrous cow{\textquoteright} model by restricting feed allowances in non-lactating cyclic cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {233-235},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This experiment aimed to characterise the ovarian response to  reducing live-weight (LWT) with the view of creating nutritional anoestrus  in cyclic cows. The ovaries of 8 non-lactating 3 yr old Friesian cows were  ultrasounded daily during 5 synchronised oestrous cycles (Rounds 1 to 5)  over 12 months. An initial live-weight of 445 },
	issn = {1176-5283},
	author = {Burke CR and Verkerk GA and Macmillan KL}
}
@conference {40822,
	title = {Hormonal induction of oestrus during the early postpartum period and the subsequent effects of nutrition on ovarian activity in dairy heifers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {230-232},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Our working hypothesis was that a significant period of severe  underfeeding of dairy heifers during early lactation would not prevent the  continuation of normal length oestrous cycles following hormonal induction  of oestrus and ovulation in the early postpartum period (pp; 26.0 ( 0.7 d pp).  Each of 16 Friesians (F) and 15 Jerseys (J) was treated with a CIDR device  for 5 days, with one injection of prostaglandin-F2a the day before device  removal and another injection 1.0 mg oestradiol benzoate 24 h after  removal. The feed allowances of 8 F and 7 J heifers were reduced over the  following 3 oestrous cycles, to a level where live-weights and milk yields  were depressed finally by up to 15\% and 36\%, respectively, compared to  fully fed contemporaries. Ovarian ultrasonography and monitoring of  concentrations of milk progesterone (mP4) during the 1st (Cyc 1) and 3rd  (Cyc 3) oestrous cycles showed that 3 Fs (1 FH and 2 FL) did not respond to  initial treatment, and remained anovulatory throughout. Another 3 heifers (2  FL and 1 JL) became anovulatory after an initial positive response. The size  of the first dominant follicle (DF1) and concentrations of mP4 were reduced  by restricted feeding, but only during Cyc 3. This study has shown that a  hormonal treatment can induce oestrus and ovulation in the majority of  heifers which have been calved between 20 and 30 days. Subsequent  restrictions in feeding level may convert some cycling heifers into an  anoestrous state, although most will continue to cycle.},
	issn = {1176-5283},
	author = {Burke CR and Macmillan KL and Verkerk GA}
}
@conference {40783,
	title = {Milk cortisol concentrations as an indicator of stress in lactating dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {77-79},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The aim of this study was to compare cortisol concentrations in  plasma (PCC) and milk (MCC) following administration of exogenous  ACTH1-24 or activation of the hypothalamo-pituitary-adrenal axis by a  stressor (transport) in cows. Fifteen cows in mid-lactation were assigned to  treatments with ACTH1-24 (0.05 mg Synacthen},
	issn = {1176-5283},
	author = {Verkerk GA and Phipps AM and Matthews LR}
}
@conference {40655,
	title = {Effects of induced parturition on mammary function},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {21-22},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Four 6.4 ha farmlets each stocked with 24 high genetic merit  Friesian cows were used to determine the effect of nitrogen fertiliser  (N), and a long summer grazing rotation on pasture and milk production  in summer. Treatments were 0 )-N) or 50 kg N/ha (+N) in December,  January and March and a 16 day (16) or 40 day (40) rotation. Treatments  started 15 December, following a two week uniformity period, and ran  until 29 April.    On the 16 and 40 day rotations N increased net herbage accumulation by  0.8 t DM/ha, and milksolids (MS) production by 92 and 38 kg/ha  respectively. Across both nitrogen treatments, the 40 day rotation  increased net herbage accumulation by 1.7 t DM/ha. The MS production  was 39kg/ha greater on the -N40 than the -N16 treatment whereas that of  the +N16 and +N40 did not differ significantly.    The N and long rotation treatments also resulted in higher average  herbage mass and cow condition at the end of the experimental period.  It is concluded that N in early summer and a long summer rotation are  useful management practices to reduce the effects of summer dry periods.   },
	issn = {1176-5283},
	author = {McFadden TB and Verkerk GA and Clark BA and Hovey RC and Macmillan KL}
}
@conference {40668,
	title = {Tail docked dairy cattle: fly induced behaviour and adrenal responsiveness to ACTH},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {61-63},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Romney crossbred lambs (n=711) sired by selected Southdown high fat   (SD+), low fat (SD-) and Texel rams were grown from weaning to 14   months of age under high(H), medium (M) or low (L) nutrition. A random   half of H and L groups were run with the L and H groups respectively from 8   months onwards. Samples of lambs were slaughtered at 3, 5, 8, 11 and 14   months of age. Whereas there were significant carcass weight differences   between nutrition and were almost always fatter than the SD- and Texel   lambs. All genotypes showed markedly reduced levels of fat development   during the post-weaning and winter periods, with highest levels in spring.   Eye muscle width was more nutritionally responsive than eye muscle depth   and, in relation to carcass weight changes, was greatest in winter.   },
	issn = {1176-5283},
	author = {Phipps AM and Matthews LR and Verkerk GA}
}
@conference {40484,
	title = {Is the welfare of dairy cows at risk from current farm practices?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {179-182},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A selection experiment to breed for high (H), control (C) or low (L) faecal egg count (FEC) levels in weaned Romney lambs was established in 1985, being maintained at Rotomahana (until weaning 1988) and at Tokanui thereafter. In winter 1990, pregnant ewes (aged 2 to 6 years) were drafted into grazing groups according to expected lambing date ({\textquoteright}early{\textquoteright} and {\textquoteright}late{\textquoteright} ewes), in order to study periparturient FEC. Non- pregnant ewes and unmated yearling females were also recorded. Faecal samples for FEC were taken from all females (n=253) before and after the pregnant ewes lambed (median lambing dates for early and late ewes being 19 August and 31 August), and then in October and in November. Lambs were also faecal sampled at 3-month weaning. A mixed model was fitted to log e (FEC + 100), with fixed effects for selection flock, group (early ewes, late ewes, non- pregnant ewes, yearlings), sample day and the interaction of group and day, and with {\textquoteright}animal{\textquoteright} as a random effect. The repeatability was 0.50 },
	issn = {1176-5283},
	author = {Hargreaves AL and Matthews LR and Verkerk GA}
}
