@conference {3672,
	title = {How does feeding meal affect growth of artificially reared East Friesian-cross dairy lambs?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {13-17},
	address = {Rotorua},
	abstract = {Artificial rearing is routinely used in large-scale dairy sheep farms. One approach is to offer milk replacer (MR) and meal ad libi-tum to lambs. Our aim was to evaluate growth performance of female lambs in the first 12 weeks of rearing with (M) and without (NM) grain-based meal access (n=30/group) during four feeding periods. In period 1 (wk 0-3) lambs were offered MR and meal ad libitum, and in period 2 (wk 4-5) were transitioned outdoors onto pasture with continued access to MR and meal. Lambs were weaned off MR in period 3 (wk 6-10), and meal in period 4 (wk 10-12). The NM lambs received identical management but meal was excluded. A treatment-by-time interaction was found whereby NM lambs had lower average daily gain (ADG) (P<0.05) in periods 1 (376{\textpm}6 vs. 414{\textpm}8 g/day) and 3 (146{\textpm}7 vs. 241{\textpm}7 g/day), no difference in period 2 (P>0.05), and higher ADG in period 4 (157{\textpm}18 vs. -55{\textpm}18 g/day, P<0.05) than M lambs. There was no difference (P>0.05) in live weight by week 12, and all lambs survived. These results indicate when lambs fed MR ad libitum are offered unrestricted access to good-quality pasture before weaning, meal may not be required to achieve a similar live weight at 12 weeks.},
	issn = {1176-5283},
	author = {Jensen AC and Khan MA and Knol FW and Peterson SW and Morel PCH and McKenzie C and Stevens DR and McCoard SA}
}
@conference {3678,
	title = {Alternative method to measure herbage dry matter (DM) mass in plantain and chicory mixed swards grazed by lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {115-120},
	address = {Napier},
	abstract = {Calibration equations are available to determine the dry matter (DM) mass of pasture using either sward height or plate meter readings. Currently there are no methods available for determining DM in a herb-clover mix other than using quadrat cuts. The objective of this research was to determine the relationships between herbage DM mass as measured by quadrat cuts vs sward height and plate meter readings for herb-clover mixes during four seasons from early spring to autumn. Pre- and post-grazing herbage DM masses (kg/ha) in the plantain mix (plantain (Plantago lanceolata), white clover (Trifolium repens) and red clover (T. pratense)) and in the chicory mix (plantain, chicory (Cichorium intybus), white clover and red clover) were estimated by collecting quadrat cuts. For each quadrat cut, a plate meter reading and five sward height measurements were also recorded. Separate regression equations were then developed for quadrat herbage DM mass vs sward height and plate meter readings. In addition, data from the plantain and Chicory mixes were pooled to obtain a data set for a combined herb-clover mix. The individual R 2 values were significant for all three relationships and ranged from 0.49 to 0.86. The concordance correlation coefficient (CCC) for all three relationships fell between 0.56 and 0.94. The relative prediction error (RPE) for all three relationships varied between 18 and 29\%. The regression equations developed by these non destructive methods, would enable farmers to obtain a reliable estimate of the herbage DM mass, with a level of precision sufficient for making day-to-day grazing management decisions on farm. The data do suggest different regression equations need to be utilised for different seasons of the year.},
	issn = {1176-5283},
	author = {Somasiri SC and Kenyon PR and Morel PCH and Kemp PD and Morris ST}
}
@conference {3678,
	title = {BRIEF COMMUNICATION: Effect of early life diet on lamb growth and organ development},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {205-208},
	address = {Napier},
	abstract = {Neonate lambs are pre-ruminants until approximately 3 {\textendash} 4 weeks of age (Treacher \& Caja 2002) and therefore their dam{\textquoteright}s milk is key to their survival and growth. During this period, their digestive system is relatively immature. Attempts have been made to evaluate the effects of early weaning on lamb growth performance with few data available at ages earlier than 4 weeks (Brown 1964; Large 1965; Walker \& Hunt 1981; Lane et al. 1986). These early studies show that lambs can be weaned at two to three weeks of age, however, they often result in growth rate checks. These findings suggest lambs require liquid diet for a minimum of two to three weeks. Nevertheless, rumen development is essential to enable lambs continue a normal growth trajectory when milk consumption ceases (Poe et al. 1969). Our objective was to examine the impacts on lamb growth and organ development when pellets are added to the milk diet of lambs in very early post birth life. Furthermore, lamb growth rates have improved by 50 g/day since the 1980s (Bray 2004). This may imply that the efficiency of lambs in utilising energy in their diet for growth and maintenance has altered. Thus, in addition to the growth performance, the utilisation of metabolisable energy (ME) in the diet for maintenance and growth was also examined.},
	issn = {1176-5283},
	author = {Danso AS and Morel PCH and Kenyon PR and Blair HT}
}
@conference {79003,
	title = {Validation of a bio-economic dairy production model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {139-143},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {DairyMax is an internet-based bio-economic dairy production model that uses a deterministic cow model to establish response curves of milksolids (MS; fat plus protein) production to energy intake at different stages of lactation and nutrient requirements for different levels of production. Another component in DairyMax is a linear programming module that uses farm-related constraints, market prices for supplements, cost of pasture and silage production and cow-related constraints to optimise a feeding strategy based on a maximum profit algorithm. The objective of this study was to validate the cow model of DairyMax against published field work conducted in New Zealand. In DairyMax, the stocking rate was adjusted to get the same MS production as in the experiment. The dry matter intake (DMI) associated with the different production levels were compared assuming energy content of 11.2 MJ ME/kg dry matter, similar to that reported in a three-year field experiment. The ability of the model was satisfactory in predicting yearly DMI per cow (Concordance correlation coefficient = 0.98). Productive performance, DMI and feed conversion efficiency (ratio between DMI and MS) of dairy cows under different stocking policies can be predicted by DairyMax with satisfactory accuracy.},
	issn = {1176-5283},
	author = {Visser A and Lopez-Villalobos N and Morel PCH}
}
@conference {75924,
	title = {Physical and physiological factors associated with twin- and triplet-born lamb heat production at 24 to 36 hours of age},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {286-290},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {This study attempted to identify physical and physiological factors of twin- and triplet born lambs within the first 24 to 36 hours of life which are associated with maximum heat production on a per lamb basis (W/lamb) and a per kg of birth weight basis (W/kg). Multiple regression analyses revealed that lamb birth weight accounted for 34 percent of the variation in maximum heat production on a per lamb basis (P <0.001), whereas, inclusion of plasma non-esterified fatty acids (NEFA; P <0.01), tri-iodothyronine (T3; P <0.05) and glucose concentrations at 24 to 36 hours of age (P <0.05) increased the accountability to 59 percent. Multiple regression analyses also revealed that plasma NEFA concentrations at 24 to 36 hours of age accounted for 15 percent of the variation in maximum heat production on a per kg of birth weight basis (P <0.01), whereas, inclusion of plasma T3 at 24 to 36 hours of age increased the accountability to 22 percent (P <0.05). Overall these results suggest that having greater lamb birth weights, plasma thyroid hormone, glucose and NEFA concentrations at 24 to 36 hours of age is beneficial for twin- and triplet-born lamb thermoregulation during periods of cold stress.},
	issn = {1176-5283},
	author = {Kerslake JI and Kenyon PR and Morris ST and Stafford KJ and Morel PCH}
}
@conference {75878,
	title = {Is there any advantage of early weaning of twin lambs born to yearlings?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {79-82},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {The objective of the current study was to investigate the effect of weaning twin lambs born to yearlings at 9, 11 or 13 weeks of age on the live weight of the yearling and her lambs. The yearlings and the lambs were allocated to one of three weaning treatment groups (9-week versus 11-week versus 13-week) on Day 1. Each treatment group was balanced for yearling and lamb live weight. At Week 13, all lambs were removed from the remainder of the experiment but the yearlings were monitored for a further six weeks. The yearlings and lambs were offered ad-libitum levels of herbage throughout the experimental period and the pre- and post-grazing mass was monitored weekly. The yearlings and lambs were weighed on Days 1, 7, 14, 21 and 28 while yearlings were weighed again on Days 35, 42 and 70. Pre- and post-grazing mass was monitored weekly. Yearling live weight did not differ (P >0.05) between treatment groups on Days 1, 35 or 70. Lamb live weight did not differ (P >0.05) on Days 1, 14 or 28. These results indicate that there is no advantage of early weaning of twin lambs born to yearlings on the live weight of the yearling or her lambs.},
	issn = {1176-5283},
	author = {Mulvaney FJ and Morris ST and Kenyon PR and Morel PCH and West DM}
}
@conference {69498,
	title = {Do lambs within twin- and triplet-born litter produce different amount of heat during a cold stress event?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {171-174},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Triplet-born lambs have been shown to have lighter birth weights (Morris \& Kenyon, 2004; Kerslake et al., 2005; Everett-Hincks \& Dodds, 2008), lower rectal temperatures (Dwyer \& Morgan, 2006; Stafford et al., 2007), lower plasma fructose (Stafford et al., 2007) and greater plasma lactate concentrations within five minutes of birth (Stafford et al., 2007; J.I. Kerslake, Unpublished data) than twin-born lambs. In addition to this, within a tripletborn litter, the lightest lambs have been shown to have lower rectal temperatures and greater plasma lactate concentrations within five minutes of birth (Stafford et al., 2007; J.I. Kerslake, Unpublished data) than the heaviest lambs. Light birth weights, low rectal temperatures and greater plasma lactate concentrations within five minutes of birth have been used as indices for placental insufficiency, acute intra-partum hypoxemia and inadequate thermogenesis after birth (Barlow et al., 1987; Mellor, 1988).},
	issn = {1176-5283},
	author = {Kerslake JL and Kenyon PR and Stafford KJ and Morris ST and Morel PCH}
}
@conference {69494,
	title = {Effect of age, live weight and dry matter intake on total tract nutrient digestibility in adult mares},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {152-156},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The effects of age, live weight (LW) and dry matter intake (DMI) on the total tract digestibility of dry matter (DDM), organic matter (DOM), energy (DE), nitrogen (DN), neutral detergent fibre (DNDF), acid detergent fibre (DADF) and minerals (DCa, DK, DMg, DNa, DP and DS) were investigated in adult thoroughbred mares. Twenty mares, aged between 7 and 16 years (mean = 11.9; standard deviation {\textpm} 3.1) and weighing 508 to 650 kg (559.5 {\textpm} 36.7 kg) were offered 13 kg of feed per day consisting of 9 kg meadow hay, 3 kg barley and 1 kg lucerne chaff. Total faeces were collected over six days following a 20 day adaptation period. The average digestibility values were DDM: 0.59 {\textpm} 0.04; DOM: 0.63 {\textpm} 0.03; DN: 0.54 {\textpm} 0.08; DNDF: 0.44 {\textpm} 0.04, DADF: 0.38 {\textpm} 0.06, DE: 0.59 {\textpm} 0.04; DCa: 0.48 {\textpm} 0.08; DK: 0.68 {\textpm} 0.07; DMg: 0.27 {\textpm} 0.11; DNa: 0.63 {\textpm} 0.13 DP: 0.17 {\textpm} 0.11; and DS: 0.59 {\textpm} 0.05. Age was only related to DS. DMI (9.16 kg {\textpm} 1.1 kg) was negatively correlated (P <0.05) with DDM, DOM and DE while LW was positively correlated (P <0.05) with DDM, OM, DN, DNDF, DADF and DE. Mineral digestibility was not affected by LW or DMI. It is concluded that feed allowances should be adjusted for LW and/or DMI when a given amount of digestible nutrients are provided. },
	issn = {1176-5283},
	author = {Morel PCH}
}
@conference {69481,
	title = {Effect of birth weight on survival of lambs born to ewe lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {101-103},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Benefits of ewe lamb mating (at 8 to 9 months of age) include improved lifetime production, increased rates of genetic gain and higher net profits (Kenyon et al., 2008 and references therein). These benefits of ewe lamb mating are only achieved if the ewe lamb successfully rears its offspring to weaning. For mature ewes, a reduction of mortality before weaning by 1\% is equivalent to an extra $10 gross margin per hectare (Morel \& Kenyon 2006). To maximise farm profits it is necessary to understand the factors that influence pre-weaning mortality of lambs born to ewe lambs so that appropriate management strategies can be implemented.},
	issn = {1176-5283},
	author = {Schreurs NM and Kenyon PR and Morris ST and Morel PCH}
}
@conference {69519,
	title = {Effect of lipid type, selenium and vitamin E on total tract nutrient digestibility in growing pigs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {266-268},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {It has been shown that the fatty acid, selenium and vitamin E content of pork can be modified by dietary inclusion of different types of fat and/or supplementation with selenium and vitamin E (Morel et al.,2008). These dietary manipulations result in pork with an enhanced nutritive value. It is generally assumed that fat digestibility increases as the ratio of unsaturated to saturated fatty acids increases (Wiseman et al.,1998). However, it is not well documented how the addition of dietary antioxidants like selenium and vitamin E will affect nutrient digestibility.},
	issn = {1176-5283},
	author = {Nuijten WGM and Morel PCH and Purchas RW}
}
@conference {69479,
	title = {Effect of nutrition around the time of breeding and during pregnancy on yearling liveweight change, pregnancy loss and liveweight and survival of of their offspring},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {91-95},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {This experiment investigated the effects of differing nutritional levels on yearling pregnancy loss, and the live weight and survival of their offspring to weaning. Yearlings were offered either Medium or Ad-libitum levels of herbage from four days prior to breeding (P-4) until P145. Nutrition during pregnancy had no effect on pregnancy loss or lamb live weight from Day 0 of lactation (L0) until L55. Lambing percent was higher (P <0.05) in the Ad-libitum treatment compared to the Medium treatment. Single born lambs were heavier (P <0.05) than twin born lambs at L0 and at L55. Ad-libitum treatment yearlings were heavier (P <0.05) than Medium treatment yearlings at L55. Modelling of the live weight trends indicated that from P-4 until P145 the pregnant yearlings in the Medium and Ad-libitum treatment groups consumed 8.1 and 14.4 kg DM/kg of lamb live weight at L55. This indicates that the greater yearling live weight gain in the Ad-libitum group utilised more herbage during the yearling{\textquoteright}s first winter without any increase in the performance of their offspring. The extra 9 kg gained by the yearlings fed Ad-libitum may have positive effects on future performance as they will gain a suitable live weight for breeding as a two year old earlier.},
	issn = {1176-5283},
	author = {Mulvaney FJ and Morris ST and Kenyon PR and West DM and Morel PCH}
}
@conference {69478,
	title = {Effects of birth rank and yearling lambing on long-term ewe reproductive performance},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {88-90},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {This experiment investigated the effects of differing nutritional levels on yearling pregnancy loss, and the live weight and survival of their offspring to weaning. Yearlings were offered either Medium or Ad-libitum levels of herbage from four days prior to breeding (P-4) until P145. Nutrition during pregnancy had no effect on pregnancy loss or lamb live weight from Day 0 of lactation (L0) until L55. Lambing percent was higher (P <0.05) in the Ad-libitum treatment compared to the Medium treatment. Single born lambs were heavier (P <0.05) than twin born lambs at L0 and at L55. Ad-libitum treatment yearlings were heavier (P <0.05) than Medium treatment yearlings at L55. Modelling of the live weight trends indicated that from P-4 until P145 the pregnant yearlings in the Medium and Ad-libitum treatment groups consumed 8.1 and 14.4 kg DM/kg of lamb live weight at L55. This indicates that the greater yearling live weight gain in the Ad-libitum group utilised more herbage during the yearling{\textquoteright}s first winter without any increase in the performance of their offspring. The extra 9 kg gained by the yearlings fed Ad-libitum may have positive effects on future performance as they will gain a suitable live weight for breeding as a two year old earlier.},
	issn = {1176-5283},
	author = {Morel PCH and Wickham JL and Morel JP and Wickham GA}
}
@conference {69518,
	title = {Review of pork-quality studies in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {261-265},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {This paper presents data published between 1990 and 2009 on pork quality in New Zealand. The characteristics considered are pale, soft and exudative (PSE), dark firm and dry (DFD), boar taint, intramuscular fat (IMF\%), chemical composition aspects such as fatty acids profile and flavours other than boar taint. Over the years the incidence of PSE has been reduced from 40\% to 6\%. The percentage of DFD pork was always below 7\%. A level of 2.0\% of IMF\% is considered as a minimum with respect to palatability. Between 1990 and 2009, reported values for IMF\% ranged from 0.98\% to 3.36\% and tended to decreased over time. Skatole and androstenone are the two major compounds responsible for boar taint. In New Zealand, males are slaughtered {\textquotedblleft}entire{\textquotedblright}. In 1996 only 19\% of them were below the European Community threshold for boar taint. Results from different feeding experiments show that the fatty acid profile, selenium content and flavours other than boar taint, of pork can easily be changed. Overall pork from New Zealand pigs is of a high quality, but the incidence of boar taint is of concern.},
	issn = {1176-5283},
	author = {Morel PCH and Purchas RW and Wilkinson BHP}
}
@conference {60955,
	title = {The effect of fasting on live weight in hogget wethers and pregnant mature ewes : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {112-114},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Withholding of food and water, or fasting, of sheep for up to 24 hours is a practice commonly employed in the agricultural industry and research sectors. Farmers routinely fast sheep before shearing, pregnancy scanning and transport. Further, with relatively large numbers of animals involved in some experiments, duration of weighing and manipulation time can vary, which may interfere with a comparison of live weight measurements. The determination of the rate of liveweight loss will allow live weights to be corrected to... Continued },
	issn = {1176-5283},
	author = {Burnham DL and Morel PCH and Kenyon PR and Morris ST and Stafford KJ}
}
@conference {60945,
	title = {The effect of weaning at 10 or 14 weeks of age on liveweight changes in the hogget and her lambs : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {68-70},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Kenyon et al. (2004) revealed via a survey, that a major reason why New Zealand farmers do not breed ewe hoggets (7-9 months old) is perceived detrimental effects on two-tooth breeding live weight, resulting in reduced two-tooth reproductive performance. Kenyon et al. (2008) confirmed this by showing hoggets that lambed had reduced two-tooth live weight and condition score at breeding. A potential means of minimising any potential negative effects on... Continued},
	issn = {1176-5283},
	author = {Mulvaney FJ and Morris ST and Kenyon PR and West DM and Morel PCH}
}
@conference {60947,
	title = {Effects of birth weight on survival in twin born lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {75-79},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Lamb survival to weaning decreases as litter size increases (single > twin > triplet > quads), with birth weight being a major factor affecting survival. The purpose of the present study was to investigate the effects of birth weight (BWT) and related traits on survival in twin born lambs. Data from a total of 3,834 twin lambs born to mixed aged ewes were analysed. For statistical analysis the lambs were allocated according to birth weight (BWT) within litter to three groups (Light = Lightest lambs within pairs, Equal = Lambs of similar weight within pairs and Heavy = Heaviest lambs within pairs). The survival rates differed (P <0.05) between Light, Equal and Heavy (80\%, 89\% and 83\%, respectively). BWT was positively related (P <0.001) to survival in the Light group, but not in the other two groups. The smaller the difference in BWT between siblings, the higher the likelihood of the Light lambs surviving. Therefore, reducing the difference in BWT within a set of twins will have the potential to increase overall lamb survival. },
	issn = {1176-5283},
	author = {Morel PCH and Morris ST and Kenyon PR}
}
@conference {41774,
	title = {Comparison of mastitis prevalence between an organic and conventional dairy herd from 2004 to 2006},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {8-11},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {This study compared mastitis bacteriology and somatic cell counts (SCC) between an organic and a conventional dairy herd, each managed as a pastoral-based system, in the 2004/05 and 2005/06 seasons. Single quarter foremilk samples taken from both herds at calving, 14 days post-calving, mid-lactation and dry-off were cultured for bacteriological analysis. Individualcow SCC were obtained from monthly herd tests. The percentage of cows infected with Staphylococcus aureusand Streptococcus uberiswas generally higher in the organic herd than the conventional herd. However, these differences were only significant for S. aureusat midlactation 2005/06, when 56\% of the organic herd was infected compared to 23\% of the conventional herd (P <0.05), and for Str. uberisat dry-off 2005/06, when 7\% of the organic herd was infected but none of the conventional herd (P <0.001). The organic herd had a significantly higher mean lactation back transformed SCC than the conventional herd, in 2004/05 (96,921 vs. 75,608 cells/mL, P <0.05) and 2005/06 (103,968 vs. 63,096 cells/mL, P <0.0001). The 2004/05 season was the first time that a significant difference in mean SCC between the organic and conventional herds had been measured, since the organic and conventional dairy systems comparison trial was established in 2001.},
	issn = {1176-5283},
	author = {McLeod KLM and Holmes CW and Morel PCH and Dowson KR and Thatcher A and Shadbolt NM and Kelly TC}
}
@conference {41691,
	title = {Milk production in Romney ewes lambing out of season},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {450-455},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Milk yield (MY) of groups of Romney ewes lambing at 3 times of the year: January (n=9), March (n=14) and June (n=13)) was measured on alternate days in the first week postpartum and at weekly intervals for nine weeks. Twin-bearing ewes produced significantly more milk than single-bearing ewes during the first week and during the whole of lactation (63 days) (P<0.05), except in the January-lambing group, in which ewes with single lambs produced more milk then those with twins during the first week. The shape of the lactation curve for ewes with singles or twins differed significantly (P<0.01) between lambing groups, reflecting that single- and twin-bearing ewes responded differently in January, but the number of twinbearing ewes was small (n=4) in that month. MY differed significantly (P<0.01) among groups lambing in January (single MY {\textpm} SEM: twins MY {\textpm} SEM) (1605 {\textpm} 57: 1402 {\textpm} 71 g/d), March (1425 {\textpm} 38; 1802 {\textpm} 46) and June (1520 {\textpm} 43: 1951 {\textpm} 54). Despite having the lowest (P<0.05) mean pre-lambing live weight (62 {\textpm} 3 kg), ewes lambing in June produced the highest overall mean MY (1735 {\textpm} 48 g/d), whilst ewes lambing in March and January had mean pre-weaning live weights of 70 {\textpm} 2 kg (in both groups) and produced 1613 {\textpm} 42 g/d and 1504 {\textpm} 64 g/d respectively. The June{\textendash}lambing ewes gained weight (1.38 {\textpm} 1.19 kg) and condition score (0.39 {\textpm} 0.16 /d) whilst weight loss was significant (P<0.05) in the March (-9.82 {\textpm} 1.15 kg) and January (-7.78 {\textpm} 1.44 kg) groups between pre-lambing and weaning, as was change in condition score (March: -0.49 {\textpm} 0.16; January: -0.63 {\textpm} 0.19). Lamb birth weights did not differ between seasons but ADG (g/d  {\textpm} SEM) was highest (P<0.01) in June (0.262 {\textpm} 0.008), followed by March (0.238 {\textpm} 0.008) and January (0.202 {\textpm} 0.009). },
	issn = {1176-5283},
	author = {Peterson SW and Morel PCH and Kenyon PR and Morris ST}
}
@conference {41678,
	title = {Sensitivity analysis of weaner lamb production in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {377-381},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Many factors contribute to the profitability of sheep farms. A sensitivity analysis, using a simulation model, was conducted to investigate the impact of changes in pasture growth, ewe live weight, conception rate, ewe prolificacy (EP), lamb survival, lamb growth rate and lamb price on farm gross margin (FGM). The model simulated herbage growth and flock energy requirement on a daily basis over a one-year period starting on the 1st January and calculated gross margins for a 500 ha farm, using average Manawatu herbage growth rates. Ewe energy requirements were calculated as a function of live weight, lambing percentage, week of pregnancy or lactation and milk production and lamb energy requirements as a function of live weight, growth rate and body composition. The pre-weaning survival rate and lamb daily growth rate were adjusted for litter size. For each simulation, stocking rates were adjusted so that the pasture cover at the beginning and the end of the year was 1200 kgDM/ha. Simulations were conducted for different farm productivity levels ({\textquoteleft}Low{\textquoteright}, {\textquoteleft}Medium{\textquoteright} and {\textquoteleft}High{\textquoteright}). Results of the simulations show that, over all farm productivity levels, lamb price and growth rate had the largest impact on FGM followed by ewe liveweight, EP, conception rate and herbage growth. However, the ranking and the effect of these parameters on FGM varied across farm types. For example in "Low productivity farms" a 1 \% increase in lamb growth rate has the same impact on FGM as a 1 \% increase in EP (+$5.4 / ha vs +$5.9 / ha) and in "High productivity farms" a 1 \% increase in lamb growth rate is equivalent to a 3 \% increase in EP (+$11.2 / ha vs +$11.1 / ha). This illustrates that for each specific farm production level there are different management strategies to optimize FGM. It was also found that the relationship between EP and FGM was not linear. Across the liveweight ranges a one percent increase in EP between 140\% and 160\% increases FGM by $3.95 /ha, between 160\% and 180\% by $2.51 /ha, between 180\% and 200 \% by $1.33 /ha, between 200\% and 220\% by $2.83/ha, and between 220\% and 240\% by $2.33/ha. Simulation models can be useful tools when considering farm management decisions as they help identify optimal management systems and identify areas that may require further research. },
	issn = {1176-5283},
	author = {Morel PCH and Kenyon PR}
}
@conference {41562,
	title = {Milk production in East Friesian-cross ewes lambing year round},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {173-177},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Milk production of groups of East Friesian cross ewes lambing at intervals of 73 days (i.e., five times per year: August (n = 21), November (n = 29), January (n = 13), March (n = 14) and June (n = 14)) was measured on alternate days in the first week post partum and at weekly intervals for nine weeks. Ewes with single and twin lambs were enrolled if they safely delivered the appropriate number of lambs indicated by previous scanning. Ewes and lambs were separated in the morning and ewes milked by machine following i.v. oxytocin (1 i.u.) and stripped by hand until empty. Ewes returned to pasture whilst lambs were housed and bottle-fed. At afternoon milking (after a precisely measured interval of about 6 h) milk yields were recorded. From that yield and the time interval, daily milk yields were calculated. Data were analysed using a mixed linear model for repeated measures. Twin-bearing ewes produced significantly more milk than single-bearing ewes (P < 0.001). Lactogenesis differed significantly (P < 0.001) between the lambing groups. Over the whole lactation, milk yield differed significantly (P < 0.001) between different lambing groups. Milk yields were highest following June lambing (2223 {\textpm} 35 g/day), followed by November (2107 {\textpm} 24 g/d), August (1932 {\textpm} 36 g/day), January (1826 {\textpm} 31 g/day) and March (1742 {\textpm} 30 g/day). A significant lambing group by rearing rank interaction (P < 0.001) indicated that single- and twin-bearing ewes responded differently to seasonal differences; ewes with twins increased milk yield proportionately more than ewes with singles in June, November and January.
KEYWORDS: milk yields; sheep; STAR system. },
	issn = {1176-5283},
	author = {Peterson SW and Kenyon PR and Morris ST and Lopez-Villalobos N and Morel PCH}
}
@conference {41557,
	title = {A study of mastitis in two small experimental dairy herds managed either organically or conventionally during one year},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {148-152},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Mastitis infection status of two small herds located at the Dairy Cattle Research Unit of Massey University was assessed. Single quarter milk samples from 45 cows under organic production (first and second year of organic certification) and 50 cows under a conventional system were taken on four occasions: mid lactation (these samples were frozen); prior to the last milking before dry-off (season 2003/2004); before the first milking after calving and 14 days post calving (season 2004/2005). Milk samples were cultured for bacterial analysis. Somatic cell counts (SCC) from monthly herd tests, and clinical mastitis cases were recorded and analyzed.
The percentages of quarters with positive bacterial growth, and SCC, were generally higher in the organic herd, but differences were only significant for Staphylococcus aureus in all four sample periods, and for Streptococcus spp. 14 days post calving. The results suggest that in organic herds Staphylococcus aureus infections could become an important concern, because of constraints on the use of antibiotic treatments. Effective prevention of infections by this organism will be essential, in order to prevent high culling rates.
KEYWORDS: mastitis; organic dairy; New Zealand. },
	issn = {1176-5283},
	author = {Silva KE and Quinn AK and Morel PCH and Holmes CW and Thatcher A and Shadbolt NM and Kelly T}
}
@conference {41500,
	title = {Economical analysis of year round lamb production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {179-182},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The traditional lamb production system in New Zealand is driven largely by the seasonal pattern of pasture growth and ewes lambing once a year. An alternative is the implementation of year-round lamb production systems such as the STAR system, where ewes lamb five times over a three-year period, thus providing a continuous supply of lambs. A modelling exercise was undertaken to assess the economic viability of the STAR system. The model simulates pasture growth and flock energy requirement on a daily basis over a three year period for both the traditional system and the STAR system and calculates gross margins. The model was run for a 100ha block using average Manawatu pasture growth rates. The two systems were set to consume 11000 kg DM/ha of pasture per year. The model indicates that, at the same lambing percentage (160\%) the STAR system earned an extra 26\% of income compared with the traditional system. Even at a lower lambing percentage (148 versus 160) the system can match a seasonal lamb production system. With a 10 \% premium for out of season lambs the STAR system generates an extra 56\% in profit. },
	issn = {1176-5283},
	author = {Morel PCH and Kenyon PR and Morris ST}
}
@conference {40550,
	title = {Influence of insulin-like growth factor-1 (IGF-1) on components of the haematopoietic and lymphatic systems},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {5-8},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Increased thymic weights have been reported in sheep selected for  
resistance to internal parasites and treatment with IGF-1 increases thymic and  
splenic weights in sheep, suggesting that IGF-1 may have a role in regulating  
immune function.  This hypothesis was examined in four experiments using  
mice as a model.  Expt 1 Unselected Swiss mice (n-24) were injected 2 x daily  
with 30 mg/d rhIGF-1 or saline for 26 days from 28 days of age.  IGF-1  
treatment increased spleen weight at a common body weight (118.2 vs 95.9,  
pooled standard error (PSE) = 6.2 mg, P<0.05), but did not affect thymic  
regression (thymic weights at the end of treatment: 85.5 vs 81.9, PSE = 4.0  
mg). Expt 2 Unselected female Swiss mice (n=22, age = 84.8{\textpm}0.8 days) were  
injected 3 x daily with 30 mg/d rhIGF-1 or saline for 17 days.  IGF-1 treatment  
increased thymic weight at a common body weight (78.4 vs 58.0, PSE = 3.0  
mg, P<0.01), but had little effect on splenic weight (180.1 vs 163.0, PSE = 7.5  
mg, P>0.10), Expt 3 Histological sections of spleens from High (H), Control  
(C), and Low (L) IGF-1 selected mice at 30 (n=30) and 120 (n=35) days of age  
were analyzed for the density of megakaryocytes (precursor cells for  
thrombocytes), and the percentage of the area covered by white pulp (lymphatic  
tissue). L mice had, compared to C and H mice, lighter spleens (62.6 vs 76.8 vs  
89.6, PSE = 5.3 mg, at 30d; 60.2 vs 109.5 vs 114.5, PSE = 7.4 mg, at 120d;  
P<0.05), and a lower density of megakaryocytes (9.2 vs 13.4 vs 14.7, PSE = 1.6  
n/mm2, at 30d; 2.1 vs 13.9 vs 14.3, PSE = 2.0 n/mm2, at 120d; P<0.05), but  
were not different in the percentage of the area covered by white pulp (16.1 vs  
14.1 vs 13.4, PSE = 1.3\%, at 30d; 28.3 vs 23.1 vs 23.8, PSE = 2.4\%, at 120d).   
Expt 4 Mice from the three IGF-1 selection lines (n=13 vs n=13 vs n=14 for L  
vs C vs H, age=86.8{\textpm}2.3 days) showed no difference in spleen weights (110.8  
vs 137.4 vs 139.0, PSE = 11.8 mg; P>0.10).  In response to an antigenic  
challenge with sheep red blood cells (SRBC), there was a small effect (P=0.10)  
of selection line on the number of plaque-forming (immunoglobulin M (IgM)- 
producing) cells (PFC) per spleen (880x103 vs 954x103 vs 1187x103, PSE =  
130x103), but the differences in anti-SRBC antibody titres (IgM) in the plasma  
(10.8 vs 11.1 vs 11.7, PSE = 0.6) were not significant.  It is concluded that  
IGF-1 affects splenic and thymic weights independently, that it influences the  
density of megakaryocytes in the spleen, and that it has an effect on the number  
of PFC per spleen in response to a SRBC challenge.  However, the biological  
significance of these effects is still to be established.},
	issn = {1176-5283},
	author = {Kuhn Sherlock B and Morel PCH and Mathis JM and Blair HT and McCutcheon SN and Marbrook J and Breier BH and Gluckman PD}
}
@conference {40352,
	title = {Responses to divergent selection for plasma insulin-like growth factor-1 (IGF-1) in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {417-422},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied  },
	issn = {1176-5283},
	author = {Morel PCH and Blair HT and McCutcheon SN and Breier BH and Gluckman PD}
}
