@conference {69463, title = {Effect of white clover containing high or low concentrations of water-soluble carbohydrate on metabolic indicators of protein degradationin the rumen of dairy cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {23-28}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {White clover has high nutritive value, but contains excess protein relative to energy, leading to the wasteful excretion of nitrogen (N) by animals. Five cycles of divergent selection has resulted in white clover lines having high (HS) or low (LS) concentrations of water-soluble carbohydrate. A grazing trial was carried out to evaluate the effect of this selection on protein utilization, using skatole and indole concentrations in the milkfat as metabolic indicators for nitrogen utilisation in the rumen. Skatole and indole arise in the rumen from the degradation of the amino acid tryptophan, and rapidly accumulate in milkfat of lactating animals fed diets rich in soluble and degradable protein. Skatole and indole concentrations were both significantly (P <0.001) lower in cows fed HS clover (356 and 84 ng/g milkfat for skatole and indole, respectively) compared to those fed the LS white clover diet (800 and 420 ng/g milkfat, respectively) suggesting protein utilisation of the HS clover was improved. Although not statistically significant in this short-term study, the trends to lower concentrations of milk urea-nitrogen and urinary-N, and the nitrogen:creatine ratio for the HS clover were in the direction expected and warrant further investigation under longer-term feeding.}, issn = {1176-5283}, author = {Higgs RJ and Cosgrove GP and Burke JL and Lane GA and Pacheco D and Fraser K and Death AF and Ford JL} } @conference {41864, title = {Clover-rich diets and production, behaviour and nutrient use by cows in late lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {42-49}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {The nutritional value of legumes for high milk production is seldom captured because grazed dairy pastures in NZ typically contain insufficient legume to satisfy the cows{\textquoteright} requirements. This paper reports interim results from a project investigating novel methods of forage presentation to cows, to enhance the contribution of legume to their diet. Four groups of spring-calving cows (n=5) in late-lactation were allocated to four treatments in a balanced, cross-over design. Two treatments consisted of spatial and temporal arrangements of grass and white clover allocated to cows as follows: i) continuous free access to grass and white clover growing separately as side-by-side monocultures (G/C) and ii) grass-only at {\textquoteleft}night{\textquoteleft} between the afternoon and morning milking and clover-only during the {\textquoteleft}day{\textquoteleft} between morning and afternoon milking (GnCd). These were compared against controls of iii) a typical mixed ryegrass-white clover pasture (Mix; an industry standard) and iv) a ryegrass-only pasture (Grass; a forage standard). Cows grazed each treatment for 8 days before moving to the next treatment in the pre-determined sequence. Measurements included milk production and composition, the time spent grazing during the day and the night (separately for grass and white clover in G/C) and the concentrations in the milk of skatole and indole, as metabolic indicators of nutrient acquisition and utilisation in the contrasting forage treatments. Cows offered G/C or GnCd produced 19.4 and 17.9 kg milk/cow/day, respectively, compared with 15.0 and 14.6 kg/cow/day when offered Mix or Grass, respectively (P=0.01, SEM=0.74). The diurnal distribution of grazing was influenced by pasture treatment (treatment x time interaction P <0.001). Cows on G/C grazed proportionately more at {\textquoteleft}night{\textquoteright} and cows on GnCd proportionately less at {\textquoteleft}night{\textquoteright} compared with Grass or Mix. GnCd constrained the cows to spend less time grazing clover than those offered G/C (245 vs. 408 mins grazing clover during 24 hrs) and more time grazing grass (253 vs. 105 mins in 24 hrs). The apparent {\textquoteleft}restriction{\textquoteleft} in GnCd to grazing clover-only during the day did not significantly reduce milk yield compared with G/C. The spatial and temporal allocations of grass and clover affected the concentrations of indolic compounds in PM and AM milk, suggesting there is scope to improve the efficiency of protein utilisation in the rumen. }, issn = {1176-5283}, author = {Cosgrove GP and Burke JL and Death AF and Lane GA and Fraser K and Pacheco D and Parsons AJ} } @conference {41357, title = {The effect of condensed-tannins in fresh Sulla (Hedysarum coronarium) on the net flux of fatty acids across the mammary gland and their secretion in the milk of lactating ewes}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {231-235}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Twelve sheep were surgically prepared with catheters in the mesenteric artery and mammary vein and a transonic flow probe around the pudendal artery to quantify the effect of condensed-tannins (CTs) on net mammary flux of fatty acids (FAs) and their secretion in milk. Two weeks later (Day 0), sheep were fed fresh Sulla (1500 g DM/d), which contains medium to high concentration of CTs (43.7 g CTs/kg DM). Six ewes were orally drenched (four times/d) with polyethylene glycol (160 g/d in water) to remove the effects of CTs; the remaining ewes received water. On Day 28, the mammary plasma flow and net flux of most FAs were similar between treatments. Arterial supply of C23:0, C18:2, C18:3, C20:1 and C22:5 to the mammary gland was increased (P\<0.10) with CTs. The increase for C18:2 and C18:3 was concomittant with increased (P\<0.10) concentrations in milk. No effect of CTs on total fat concentration and yield in milk was observed. Conclusions from this study indicate that CTs in Sulla increased the milk concentration of C18:2 and C18:3 by increasing arterial supply of these FAs to the mammary gland.

}, issn = {1176-5283}, author = {Roy NC and Knight TW and Reynolds GW and Deighton MH and Death AF and Sinclair BR and Peters JS and McNabb WC} } @conference {41177, title = {Effects of yarding and transport on muscle glycogen concentration in beef cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {124-125}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Low ultimate-pH of beef is desirable because it enhances shelf life, colour and tenderness. Pre-slaughter stress is thought to deplete muscle glycogen and in extreme cases lead to higher ultimate pH of beef. Seventeen-month-old steers were allocated to three treatments (n=15): Control (C, grazing on pasture), Yarded (Y, held for 24 hours in cattle yards) and Yarded plus Transported (YT, as for Y but also trucked for 4 hours during the 24-hour yarding period). The Y and YT animals lost weight (average 25.5 kg) during time off pasture. Plasma glucose and lactate did not differ across treatments. Plasma cortisol and creatine kinase concentrations were increased by YT and plasma non-esterified fatty acids concentration by both Y and YT. Despite these indicators of occurrence of mild stress, especially in YT, muscle (longissimus dorsi) glycogen concentration was not influenced by treatments. Results suggest that increased emphasis on improved animal handling during yarding and trucking of cattle is unlikely to markedly lower the incidence of high-pH beef. }, issn = {1176-5283}, author = {Lambert MG and Knight TW and Cosgrove GP and Death AF and Anderson CB} } @conference {41183, title = {Reducing fat colour in beef by grazing steers on turnip bulbs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {143-146}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Feeding steers for 10 weeks on the residual turnip bulbs left after grazing the green tops off with lambs plus low carotenoid supplements, reduced carotenoid concentrations in the carcass fat by 38-43\% and fat colour by 14-31\% compared with steers grazing pasture. The steers on the turnip bulbs were fed a daily supplement of 0.5 x 10-1 IU of vitamin A in pelleted barley grain plus pasture silage, hay, and malting corms. The turnip bulbs comprised approximately 42-47\% of the diet. The growth rate of the steers on turnip bulbs was higher (P < 0.001) than for steers on pasture (0.71 kg head-1day-1 versus 0.45 kg head-1 day-1). There were no effects of grazing the steers on turnip bulbs on the other meat characteristics measured, including the odour and taste. }, issn = {1176-5283}, author = {Knight TW and Death AF} } @conference {41040, title = {Exercise effects on muscle glycogen concentration in beef cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {243-244}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Low ultimate-pH of beef is desirable because it increases shelf life and has beneficial effects on colour and tenderness. Industry recommendations are that beef animals are not exercised strenuously prior to trucking, as this may trigger depletion of muscle glycogen and lead to higher beef pH. In 2 experiments, 400-500 kg 18-month-old steers were exercised at a range of intensities up to 5 km distance at 8 km/hr. Biopsy samples from the longissimus dorsi muscle were taken and glycogen concentration measured. Although plasma lactate levels were elevated by exercise there was no significant depletion in muscle glycogen concentration (average 17.7 mg/g tissue). Depletion may have occurred had animals been heavier and fatter, or if the exercise regime had been more severe. Alternatively, it may be that at the level of exercise imposed (which was severe by farm-practice standards), animals also needed to be emotionally stressed in order to precipitate a depletion of glycogen, through a combination of muscle contractile and adrenergic reactions. }, issn = {1176-5283}, author = {Lambert MG and Knight TW and Cosgrove GP and Anderson CB and Death AF and Fisher AD} } @conference {41044, title = {The relationship between carotenoid concentration and fat colour in beef carcasses}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {256-258}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Relationships between carotenoid concentration, chromameter (L* a* b*), and subjective measurements of fat colour were calculated from 15 mobs of cattle. Carotenoid concentration accounted for 60\% of the variation in b* (n=514), but b* accounted for only 16\% of the variation in subjectively measured fat colour (n=732). Neither the inclusion of other variables (e.g. carcass weight or fat depth) nor transformation of the data substantially improved these relationships. }, issn = {1176-5283}, author = {Knight TW and Death AF and Boom CJ and Litherland AJ} } @conference {40926, title = {Age at castration after puberty has no effect on carcass weight.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {196}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Bulls grow faster than steers but produce meat with lower quality, which presents fewer marketing opportuni-ties. Castration post-puberty improves several attributes of meat quality compared with bulls and theoretically it could be used to exploit the faster growth rates of bulls. How-ever, the 23 kg liveweight advantage of bulls over steers, when surgically castrated at 17 months-of-age, was lost in the subsequent 5 months to slaughter, because of poorer post-castration growth rate (Cosgrove et al.1996). It was not clear whether this was because of stress from surgical castration, or physiological effects associated with their age at castration. This trial examined the effect of age at castration on subsequent growth rate and carcass character-istics at slaughter.}, issn = {1176-5283}, author = {Cosgrove GP and Knight TW and Death AF and Lambert MG} } @conference {40907, title = {Is beef with yellow fat healthier for you than beef with white fat?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {134-136}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Fat samples were collected from 20 Angus grass fed steers 24 hours after slaughter. Fat colour was measured with a Chromameter (b* values) and the carotenoid concentration and fatty acid (FA) composition of the fat were analysed. Carotenoid concentration in the fat was low (1.54 {\textpm} 0.11 mg/g fat) compared to that found in vegetables. As b* values, and therefore the yellowness of the fat increased the proportion of saturated FA decreased (r = -0.58; P<0.001) and mono-unsaturated FA increased (r = 0.68; P<0.0001). The relationship was not as strong for carotenoid concentration even though the correlation between carotenoid concentration and b* values was high (r - 0.86; P<0.001). The conclusions were that the potential health advantages of beef with yellow fat compared to beef with white fat were small, especially as the relationships appeared to only apply within a herd. }, issn = {1176-5283}, author = {Knight TW and Death AF} } @conference {40899, title = {Measures of stress and growth suppression in surgically castrated bulls}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {57}, year = {1997}, month = {Jan}, pages = {100-104}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effects of surgical castration of pre- and post-pubertal bulls on measures of stress and growth were investigated in two separate experiments. In Experiment 1, 17-month-old Friesian bulls (n = 6 per treatment) were either left untreated (Controls), handled and administered local anaesthetic (Handled), or handled, administered local anaesthetic and surgically castrated (Castrates). In Experiment 2, 5-month-old Friesian bulls (n = 10 per treatment) were either left untreated (Controls) or surgically castrated without local anaesthetic (Castrates). Castrates in Experiment 1 had higher (P<0.05) plasma cortisol concentrations 7 and 14 days after treatment compared with Handled bulls and lower (P<0.01) gains in body weight for 14 days compared with Controls. There were no effects of treatment on plasma non-esterified fatty acid, b-hydroxybutyrate and urea concentrations. Castrates in Experiment 2 had higher (P<0.05) plasma concentrations of cortisol and the inflammatory protein haptoglobin for 7 days after treatment compared with Controls. The feed intake and weight gain of Castrates were also lower (P<0.05) than that of Controls during the week following treatment. It is concluded that the castration of cattle causes stress, resulting in a check in growth which is possibly mediated via a reduction in feed intake. }, issn = {1176-5283}, author = {Carragher JF and Knight TW and Death AF and Ingram JR and Matthews LR} } @conference {40812, title = {Brief Communication: Effect of dietary vitamin A on plasma carotenoid concentration and fat colour in cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {193-194}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {In two trials using cattle grazing green pasture, daily supplements of 1x106 IU vitamin A decreased plasma carotenoid (PC) concentration by 43- 58\% over 28-31 days. Neither increasing the dose of vitamin A to 2.5 x 106 IU nor continuing the supplement for 83 days further reduced PC concentrations. These decreases in PC concentrations were not accompanied by decreases in carotenoid concentration in the subcutaneous fat or fat colour. This was possibly because PC concentration was still too high to allow a loss of carotenoids from the fat depots. }, issn = {1176-5283}, author = {Knight TW and Death AF and Wyeth TK} } @conference {40800, title = {Effect of iodine supplementation on milk iodine concentrations and productivity of dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {143-145}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Iodine (I) concentrations in New Zealand pastures are low and may be inadequate to meet the I requirements of lactating dairy cows. A trial was undertaken with 400 cows to determine the effects of a single intra-muscular injection of 2000 mg I (in popyseed oil) given at the beginning of lactation on cow performance. The pasture I concentration ranged between 0.17-0.26 mg I/kg DM during of the trial and the supplement increased serum thyroxine (T4) and milk I concentrations for 76 (P<0.05) and 170 (P<0.01) days respectively. Iodine supplementation did not affect milk yield milk composition or number of services per conception. To increase I status and maintain milk I concentrations at or above 40 }, issn = {1176-5283}, author = {Grace ND and Waghorn GC and Mills AR and Death AF} } @conference {40867, title = {Effects of post-pubertal castration and diet on growth rate and meat quality of bulls}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {390-393}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {By castrating bulls post-puberty and then finishing before slaughter it may be possible to obtain both the higher growth rate of bulls but the meat quality of steers. Of 50 crossbred bulls, 20 were castrated at 10 months-of age (steers) and 20 castrated at 17 months-of age (castrates). One month after the latter castration, all animals commenced a 100 day finishing period and were slaughtered at the end. Ten steers and 10 castrates were fed a diet of 50\% barley : 50\% silage while the rest grazed brassica crop and pasture. Bulls were 20 kg heavier than steers at post-pubertal castration (388 }, issn = {1176-5283}, author = {Cosgrove GP and Knight TW and Lambert MG and Death AF} } @conference {40869, title = {Plasma carotenoid concentrations early in life can be used as a selection criterion for fat colour in heifers}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {398-399}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Plasma carotenoid (PC) concentrations were measured at 2-5 month intervals in 20 Hereford x Jersey (HJ) and 20 Hereford x Friesian (HF) once bred heifers from 10-35 months-of-age. Half of the heifers were slaughtered at 31 months-of-age and the rest at 35 months-of-age. The colour of the subcutaneous and intermuscular fat was measured using a chromameter and c* values were calculated. Subcutaneous and intermuscular fats in HJ heifers were yellower (i.e. they had higher c* values) than in HF heifers. Regression equations that included breed, date of slaughter and PC concentrations at 10-12 months-of-age, accounted for 56\% of the variation in c* values for subcutaneous fat and 40\% of the variation in c* values for intermuscular fat (P<0.001). }, issn = {1176-5283}, author = {Death AF and Knight TW and Purchas RW and Morris ST and Burnham DL} } @conference {40702, title = {The relationship between daily Se intakes and blood Se concentrations in pregnant dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {174-175}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {In ruminants protection against environmental pathogens in the early post-natal period is largely dependent on passively-acquired immunity from maternal colostrum since evidence suggests placental transfer of antibody does not occur. Our overall aim is to develop antibody based treatments for protection of neonatal animals. In this study we have re-examined aspects of maternal antibody transfer to offspring especially in the light of recent evidence that feeding specific antibodies to neonatal rats decreases subsequent immune responses to the corresponding antigen. In experiment 1, pregnant ewes immunised with model antigen (human growth hormone) were terminated at 135 days gestation and blood samples collected from the ewe and fetus. Analysis of fetal plasma by antibody dilution/tracer binding assay procedures produced no evidence of antibody transfer to the fetal circulation via the placenta. In a further study the kinetics of specific antibodies were examined in lambs from immunised ewes. One group of lambs was permitted to suckle from the ewe for the duration of the trial (40 days) whereas the other group was permitted initial sucklings only, separated from the ewe 24 hours post partum and then fed a milk substitute. Analysis of specific antibodies titres revealed a very similar trend in both the amount of antibody transferred to lamb plasma and its persistence with the half-life for both groups calculated at approx. 13 days In the second experiment lambs from ewes immunised during pregnancy against E.coli and fed specific antibodies via maternal colostrum as neonates were compared to a matched control group of lambs derived from non-immunised ewes for subsequent immune responses against the same antigen. Peak antibody titres as analysed by ELISA were lower in lambs from immunised ewes than in control group lambs (mean titre (-log 10) 5.29 }, issn = {1176-5283}, author = {Grace ND and Mills AR and Death AF} } @conference {40565, title = {Comparative performance of Angus cattle and swamp buffalo fed ad libitum either a lucerne hay and concentrate ration or pasture hay.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {67-70}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Voluntary intake and liveweight gain of Angus cattle (CAP) and swamp buffalo (B) were compared on 2 feeds; ad lib., lucerne hay (L) + 1 kg concentrate/animal/day (LC) and ad lib. pasture hay (P) in a 2 x 2 Latin square designed trial. The two hays had similar ME values; L, 8.5 and P 8.7 MJ/ME/kg DM, but differed (P<0.05) in protein content; L, 14.6\% and P 10.1\%. The concentrate was 13.5 MJ ME/kg DM and 14.1\% protein. Animals were fed in a feed-lot with individual pens/treatment. Intake was assessed on a group basis for all treatments and individual animal intake was assessed for the P treatments only using slow release chromium capsules. Two, 4 week experimental periods were preceded by a 2 week feed adjustment period. Liveweight gains showed a species x fed interaction (P<0.001) with individual treatment gains (kg/day) of; 0.80, -0.54, -0.02, -0.09 for CLC, CP, BLC, and BP groups respectively. Cattle consumed (group assessment) more (P<0.05) L Hay than buffalo; 127 vs 99 g DM/kg LWT0.75. The intake of P hay was similar for each species; 102 and 100 g DM/kg LWT0.75 for C and B respectively. The release of CR2O3 from the capsules were similar for the two species (1.56 g/day). Intakes of P hay assessed by the marker techniques differed (P<0.05); 100 and 88 g DM/kg LWT0.75 for the CP and BP treatments respectively. The difference in performance of the two species on P may have been the result of the marginal (for cattle) protein levels. No explanation is given for the poor performance of buffalo on the LC ration. }, issn = {1176-5283}, author = {Thomson NA and Death AF and Power MT} } @conference {40579, title = {Effect of breed on plasma carotene concentration in New Zealand dairy heifers}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {119-120}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Factors affecting plasma carotene concentration were investigated in New Zealand dairy heifers. Blood samples were collected from 4000 dairy heifers in spring in November 1992. Significant (P<0.001) variation was found in plasma carotene concentrations due to region, breed and farm. Values for individual cows ranged from 1.7 to 56.2 ug/ml. Purebred Jersey heifers had the highest plasma carotene levels (18.2 {\textpm} 0.4 ug/ml), purebred Friesians the lowest (14.4 {\textpm} 0.2 ug/ml), crossbreds were intermediate with 50\% Jersey and 50\% Friesian significantly different from the purebreds (16.9 {\textpm} 0.6 and 15.4 {\textpm} 0.4 ug/ml respectively). }, issn = {1176-5283}, author = {Newman S-AN and Knight TW and O{\textquoteright}Neill KT and Death AF and Ridland M} } @conference {40523, title = {Awassi lamb performance in New Zealand quarantine}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {343-346}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Effects of preslaughter stress and postslaughter ageing regimes on calpain activities and indicators of meat quality were investigated in lambs selected for Fast and Slow glucose clearance (GC). Loins were aged at 11- 17 C for 4, 22 or 70 hrs and then stored frozen (-20 C) or chilled (0 C). Loins aged up to 70 hrs from Fast GC lambs that were exposed to a high level of preslaughter stress had the highest pH and lowest residual glycogen (P<0.05). Calpain activity and cooked meat shear force declined rapidly over the periods of ageing, with significant differences being found between 4 and 22, 22 and 70 hrs aged loins (P<0.05). At the same time pH increased, with a significant difference observed between 4 and 70 hrs aged loins (P<0.05). This data suggests that there is a potential conflict between the beneficial effects of ageing on tenderness and the adverse effects of ageing on the elevation of pH. Calpain I and II activities declined at different times after slaughter in loins aged 22 hrs and then stored chilled for 8 weeks. The loss in calpain I activity was closely associated with a large reduction in shear force over the first 22 hrs after slaughter. The results suggest that an understanding of the factors that control calpain activities may identify methods of improving meat tenderness.}, issn = {1176-5283}, author = {Hill FI and Ryan T and Death AF} } @conference {40547, title = {Brief Communication - Effects of stress and nutritional changes on the ranking of cattle on plasma carotene concentrations}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {455-456}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The ability of endocrine manipulation of the neonate to effect prolonged changes in body composition was examined. Treatment of lambs with recombinant bovine somatotropin (rbST) at doses of 0.1 or 0.3 mg/kg liveweight/day for 11 weeks from birth elevated circulating ST concentrations (P<0.01) but had no effect on circulating concentrations of insulin-like growth factor-1 or on liveweight gain compared with excipient-treated lambs. However, at 8 months of age (5 months after cessation of treatment), ultrasound backfat depths (Mean}, issn = {1176-5283}, author = {Knight TW and Ridland M and Hill FI and Death AF and Wyeth TK} } @conference {40543, title = {Brief Communication - Time and incidence of foetal mortality in alpacas}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {437-438}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The deficiency of uridine monophosphate synthase is a disorder of the de novo pathway for pyrimidine nucleotide biosynthesis. Inherited as an autosomal recessive, it results in early embryonic mortality for the homozygous recessive genotype. In the mid-1980{\textquoteright}s, heterozygotes were estimated at 1 - 2\% among US Holstein cattle. The institution of a testing program for carriers and refusal by US artificial insemination companies to accept carriers into their progeny testing programs has eliminated the condition from the top 400 US Holstein bulls. Bovine citrullinaemia is a defect of the urea cycle. Also inherited as an autosomal recessive, it results in early postnatal mortality for the homozygous recessive genotype. In 1990, heterozygotes constituted 0.3\% of US Holstein cattle. At present, no known carriers are among the top 400 US Holstein bulls. Carriers for either condition can be detected by convenient and inexpensive DNA based testing. To guard against these conditions reappearing, a modest testing program among prominent US bulls should be continued and importers should insist that imported Holstein germplasm have no evidence of these conditions. }, issn = {1176-5283}, author = {Ridland M and Knight TW and Wyeth TK and Death AF} } @conference {40537, title = {A comparison of carcass and meat characteristics and organ weights of castrate and entire male buffalo and cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {407-412}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Research has shown that sheep from a Massey University flock selected for increased fleece weight (FW) for thirty-six years have higher faecal egg counts (FEC) than unselected controls (C). The purpose of this trial was to determine whether differences in FEC between FW and C sheep accurately reflected differences in adult worm burdens. In addition levels of mucosal mast cells, and their relationship with worm burden in each line were examined. Thirteen one year-old rams from each flock were housed indoors and artificially infected with larvae of three species of nematode parasite: Haemonchus contortus, Ostertagia circumcincta, and Trichostrongylus colubriformis. FECs were monitored and adult worm burdens, and levels of mucosal mast cells, determined following slaughter 28 days after infection. FECs were higher in FW than C sheep (4204 vs 300 epg, p<0.0001), as were numbers of adult Haemonchus (1151 vs 249, p<0.01) and Ostertagi (2268 vs 600, p<0.05). Numbers of Trichostrongylus (5838 vs 5266) and total worm burden (9257 vs 6115) were not significantly different between lines. A {\textquoteright}Total Pathogenic Index{\textquoteright}, calculated from the number of parasites of each species present in the total burden, was higher in FW than C sheep (3.8 vs 1.5, p<0.005). The regression coefficient relating FEC to worm burden was larger in FW than C sheep (0.35 vs 0.05 eggs per g faeces/worm, p<0.01). Levels of mucosal mast cells did not differ significantly between lines, but were inversely related to number of worms in FW sheep. There was no such relationship in C sheep. It is concluded that while the large differences in FEC between lines overestimates the difference in total worm burden, FW sheep do carry significantly more worms of the abomasal species H. contortus and O. circumcincta than C sheep. FW sheep are able to maintain superior wool production in spite of this potentially more pathogenic worm burden. The mucosal mast cell response to parasitic infection also appears to have been changed by selection. }, issn = {1176-5283}, author = {Purchas RW and Thomson NA and Waghorn GC and Death AF} } @conference {40519, title = {Skin follicle development in South African (SA) and SA x New Zealand Angora goats}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {327-330}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The expected value of the solution of the differential equation arising from the allometric hypothesis when the variables are random is found. This solution differs from the deterministic solution, so that predictions using the allometric equation which ignore the stochastic nature of the differential equation are biased. When lease squares estimation is carried out using the deterministic solution, ignoring the stochastic nature of the size variable, the estimate of the constant coefficient of the allometric equation may be severely biased. An example shows mild bias in estimates of the maturity parameter, but large bias in the estimate of the constant coefficient. To obtain unbiased estimates of the parameters in the allometric equation a factor equal to the reciprocal of the square of the size variable must be added to the usual log-log regression used to calculate estimates of the parameters. These results have application to models based on the allometric hypothesis, in particular models which are used in studies of carcass composition and the description of maintenance requirements in animal nutrition. When these models are used for prediction they need to be modified to account for any random variation occurring in the size variable.}, issn = {1176-5283}, author = {Parry AL and Death AF and Dick HB and Miller CM and Craven AJ} } @conference {40368, title = {Oestrus synchronisation and oestrus detection in Swamp Buffaloes (Bubalus bubalis)}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {25-28}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Selective mating of Perendale sheep for increased or reduced susceptibility as lambs to an experimental challenge with Haemonchus contorus commenced in 1986. Four years later changes were assessed by monitoring faecal nematode egg count (FEC) in ewes and their progeny. In the absence of drenching, mature flock ewes were given 7000 infective larvae of H. contortus and 3000 larvae of Trichostrongylus colubriformis in mid May 1990 after mating. FEC were monitored at regular intervals during pregnancy and 4 times during the periparturient period. Ewe and ram lamb progeny were faecal sampled on 5 occasions between weaning (November 1990) and May 1991. Lambs were drenched at most sampling dates. All stock were grazed across pasture contaminated previously with mixed parasite populations. Adult ewes selected as lambs for Resistance (low FEC) shed fewer eggs than Susceptible (high FEC) line ewes throughout pregnancy, 2 weeks pre- and 3, 6 and 9 weeks post-parturition. At the periparturient peak, approximately 3 weeks after lambing, Low FEC line ewes maintained FEC which were only 25\% of those in the High FEC line. Lambs from the Low FEC line had significantly lower FEC than their High counterparts on 3 of 5 sample dates (P<0.01). At the final sample date (30 April 1991), there was a 10-fold difference in mean FEC between extreme sire groups. Bulked faecal cultures demonstrated that Haemonchus and Trichostrongylus were the dominant genera. }, issn = {1176-5283}, author = {Hill FI and Knight TW and Death AF and Wyeth TK and Ridland M} } @conference {40231, title = {Concentration of melatonin in plasma of goats treated with Regulin}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {297-300}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Sustained release of melatonin from implants or microcapsules administered in October induced cashmere growth during November to March in all ten, treated, cashmere-bearing goats. The mean maximum length of the cashmere in this induced fleece ranged from 12-55mm. Another cashmere growth cycle followed between autumn and winter. In contrast, nineteen control goats grew cashmere only during the autumn-winter period. Melatonin treatment increased total mean cashmere staple length by up to 65\% for treated animals compared with controls. The onset of growth of the autumn fleece in the treated goats was delayed as also was the time when maximum length was achieved on shedding occurred. Melatonin treatment should permit the shearing of the autumn fleece to be delayed, thus reducing the risk of post-shearing losses during inclement weather in late winter. }, issn = {1176-5283}, author = {Parry AL and Paterson DJ and Litherland AJ and Death AF and Staples LD} }