@article {3672, title = {Associations of body condition score and change in body condition score with lamb production in New Zealand Romney ewes}, journal = {New Zealand Journal of Animal Science and Production}, volume = {79}, year = {2019}, month = {07/2019}, pages = {91-94}, address = {Palmerston North}, abstract = {Body condition score (BCS) is an on-farm subjective measurement used to inform feed management decisions in sheep. This study determined the associations of BCS and changes in BCS on production. Ewe BCS was recorded four times annually in a flock of 2534 Romney ewes aged one-five, first bred at eight-months of age. Production was measured as the number of fetuses scanned (NLS), number of lambs weaned (NLW), average weight of lambs weaned (WWT) and total weight of lamb weaned (TLW). Ewe BCS was greatest at lambing and lowest at weaning. At pregnancy scanning (at an average of 75 days of pregnancy), two weeks prior to lambing, and at weaning, BCS >=4.5 was associated with the lowest NLS and NLW, but the greatest WWT. Ewes with a BCS <=2.5 at weaning were associated with the greatest TLW, suggesting these ewes had utilised their stored body fat to achieve high milk yields. Ewes that decreased BCS between lambing and weaning produced greater (P<0.05) TLW compared with ewes which maintained or gained BCS indicating their body reserves were acting as a buffer for milk production. The results of the current study showed that there was an effect of BCS on NLS, NLW, WWT and TLW. The change in BCS from scanning to weaning is an important determinate of NLW, WWT and TLW. A further study with more focus on the change in BCS is, therefore, warranted.}, issn = {1176-5283}, author = {Tait IM and Kenyon PR and Garrick DJ and Lopez-villalobos N and Pleasants AB and Hickson RE} } @article {3672, title = {Genetic and phenotypic correlations between production traits and adult body condition scores in New Zealand merino ewes}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {71-75}, address = {Lincoln}, abstract = {Genetic and phenotypic correlations between adult body condition scores (BCS) throughout the production cycle and eye muscle depth, fat depth, two-year-old greasy fleece weight, fibre diameter, staple length and staple strength were estimated from 2,007 pedigree-recorded merino ewes born between 2013 and 2015. The heritability estimates of BCS at pre-mating, mid-pregnancy, pre-lambing and weaning were 0.66, 0.39, 0.46 and 0.32 respectively. The heritability estimates for yearling greasy fleece weight, fibre diameter and staple length were 0.65, 0.86 and 0.73 respectively, and all these traits were positively genetically correlated with BCS. The genetic correlations among the four BCS measurements ranged from 0.39-0.83, while the phenotypic correlations ranged from 0.22-0.45. Genetic correlations between BCS and fat depth ranged from 0.67 to 0.83. Given the high heritability of BCS and high genetic correlations between BCS measurements, there is clear scope for selection to alter BCS. Mating appears to be the best time to record BCS for genetic selection, as it had the greatest heritability estimate and the greatest genetic correlations with ultrasound measurements of fat depth and eye-muscle depth and all wool traits except fibre diameter coefficient of variation and greasy fleece weight.}, issn = {1176-5283}, author = {Tait IM and PR Kenyon and Garrick DJ and Pleasants AB and Hickson RE} } @conference {3672, title = {Effect of cow body condition score on inter-calving interval, pregnancy diagnosis, weaning rate and calf weaning weight in beef cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {77}, year = {2017}, month = {06/2017}, pages = {23-28}, address = {Rotorua}, abstract = {The aim of this study was to describe the effect of cow body condition score (BCS) on pregnancy rate, inter-calving interval, wean-ing rate and birth and weaning weights of calves. Measurements of BCS in a herd of mixed age (2-10 years), predominantly Angus, beef cows were recorded annually four times between November 2012 and March 2015, at joining/rebreeding (November), wean-ing/pregnancy diagnosis (PD, March), winter (June) and calving (August). Year influenced BCS (P<0.05) and BCS was greatest at weaning 2014. Two-year-old cows had greater BCS (P<0.05) than three-year-old and the mixed age cows. Pregnancy rate was no different (P>0.05) between BCS at calving, joining and PD. Cows that increased BCS from joining to PD had lower pregnancy rate than cows that maintained or decreased BCS during this period, although it is unclear whether this association reflects an influence of BCS on pregnancy rate, or whether the BCS change was a result of differing pregnancy status. Greater BCS at joining was associated with lower calf birth weights. Body condition score at each event was not associated with inter-calving interval or calf weaning weight. Further research is still required to determine the optimum BCS at each stage of the production cycle.}, issn = {1176-5283}, author = {Tait IM and Morris ST and Kenyon PR and Garrick DJ and Pleasants AB and Hickson RE} } @conference {41675, title = {Eating quality of commercial meat cuts from Australian lambs and sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {363-367}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Triplets occur when lambing percentages exceed 130\%. When triplets are left with their dam, survival is often less than 75\%. Artificial rearing of onelamb from each set of triplets offers the chance to increase survival rates. But experience to date has frequently resulted in death rates of10\% to 30\% of lambs. On the author{\textquoteright}s farm about 100 sets of triplets are born each year. In 2002 an artificial rearing system was put in place based on the Poukawa system. The smallesttriplet from each set was removed for artificial rearing. In 2002 and 2003, when lambs were 3 to 5 weeks old, up to 25\% died. A worldwide information search suggested that the disorder was possibly abomasal bloat. A Norwegian method of preparing {\textquotedblleft}soured{\textquotedblright} milk replacer that had been demonstrated to limit abomasal bloat was adapted for New Zealand conditions. Lambs are fed cow colostrum for two days, followed by ad lib. cold {\textquotedblleft}soured{\textquotedblright} whole milk replacer and ad lib. meal. In 2004 and 2005, there have been no deaths due to abomasal bloat. Total deaths from 199 lambs have been 9. Live weight gains of the lambs have been 220-250 grams per day till 8 weeks.}, issn = {1176-5283}, author = {Pethick DW and Pleasants AB and Gee AM and Hopkins DL and Ross IR} } @conference {41843, title = {Mathematical modelling of anoestrus in dairy cows and the linkage to nutrition}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {324-328}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Postpartum anoestrus is a major reproductive problem in New Zealand dairy cows and its duration is related to the nutrition levels both pre and post calving. However, the mechanistic details of this relationship are largely unknown. A better understanding of the interactions between nutritional status, and the levels of the reproductive hormones controlling follicle development and ovulation is needed. A mathematical model consisting of a set of interactive nonlinear differential equations and describing the dynamics of the interactions among luteinising hormone (LH), follicle stimulating hormone (FSH) and oestradiol was developed. The model depicts oestradiol profiles generated by individual follicles from the first follicular wave after calving until ovulation, and changes in LH pulsatility leading to the first pre-ovulatory surge are also produced. The robustness of the model was ascertained from iterative processes, and it was also checked against existing experimental data so as to mimic observed changes in hormone levels. It was shown that two mathematical parameters which control: i) the speed of changes in the feedback of LH activity to oestradiol; and, ii) the sensitivity of the ovarian response to LH, have the greatest effect on duration of anoestrus. KEYWORDS: mathematical model; anoestrus; dairy cows; nutrition; oestradiol; LH; FSH. }, issn = {1176-5283}, author = {Smith JF and Soboleva TK and Peterson AJ and Pleasants AB and Chagas LM and Burke CR} } @conference {41844, title = {Relationships among metabolic hormones, luteinising hormone and anoestrus in periparturient dairy heifers fed two nutritional levels prepartum}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {329-334}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {A mathematical model that describes the dynamics of reproductive hormones was developed to estimate the duration of the postpartum anoestrus interval (PPAI) in cows. The model identified two relatively separate mechanisms: one influenced PPAI through luteinising hormone (LH) release; and it is suggested that another one controlled ovary sensitivity to LH. Examining the role played by these mechanisms in the relationships between nutrition and PPAI involved analysing the data from an experiment that measured the effects of prepartum nutrition on PPAI in which levels of insulin-like growth factor-I (IGF-I), insulin, glucose, leptin and growth hormone (GH) were recorded. Five months before calving, 30 Holstein-Friesian heifers were randomly allocated to a high (HP) or low plane (LP) of nutrition. Body condition scores at calving were 6.3 and 4.1 for the HP and LP treatments respectively. Both groups were fed ad libitum after calving. Secretion patterns of LH were measured at 2, 5 and 8 weeks after calving. PPAI differed between treatments (HP 62.0 {\textpm} 7.95 days; LP 83.1 {\textpm} 6.95 days; P < 0.05), as did the level of GH at calving (HP 5.8 {\textpm} 1.23 ng/ml; LP 10.3 {\textpm} 1.23 ng/ml; P < 0.001). The within treatment variation in PPAI was partitioned into that associated with LH frequency post calving and that orthogonal to LH pulse frequency. Within each treatment, GH was associated with the LH frequency and insulin was associated with the component orthogonal to LH frequency. These results link nutrition to the PPAI through the dynamics of insulin and GH. KEYWORDS: mathematical model; anoestrus; dairy cows; nutrition; metabolites; LH. }, issn = {1176-5283}, author = {Pleasants AB and Chagas LM and Burke CR and Smith JF and Soboleva TK and Peterson AJ} } @conference {41467, title = {The effect of pre-calving and post-calving nutritional regimes on calf birth weight and pre-weaning growth}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {36-38}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Numerous studies with New Zealand beef cattle have been carried out to determine responses of live weights or reproductive/survival traits to changes in the level of nutrition, at various stages during the annual production cycle. Various studies have also been carried out to describe how much of the variation for these traits of the cow or calf is genetic. This brief summary explores the possibility that some of these cattle data could be re-evaluated because of their possible relevance and analogies to current medical questions of interest. }, issn = {1176-5283}, author = {Morris CA and Smeaton DC and Pleasants AB} } @conference {41461, title = {Growth and development contract session}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {17}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

In 2003 the Centre of Research Excellence (CoRE) for Growth and Development was formed. The purpose is to conduct research into growth and development, focussing particularly on the issues of pre- and post-natal growth and its implications for human health.
The medical challenges for the developed world are those associated with the nutritional environment, obesity and the associated illnesses of diabetes and cardio-vascular disease. There is evidence linking the propensity for these diseases to the nutritional status of the fetus in the first trimester of pregnancy and the interaction of this status with nutrition in the immediate post-natal period. In this respect the problem differs from the issues considered by animal production. Here the last trimester of pregnancy has received the most attention, and few domestic animals live long enough for cardio-vascular problems to arise. Nevertheless the skills and methods of investigation developed by animal scientists can be applied to these new problems.
Animal production research and medical science have much to offer each other, but with a few notable exceptions this potential has not been realised. A cursory look at the references listed by the authors in this contract shows little evidence of contact. One of the goals of the CoRE is to promote this interaction. This contract session with the New Zealand Society of Animal Production has two goals. First, to make animal scientists aware of the questions facing medical scientists with respect to early growth and development, the focus of the CoRE effort. Second, to encourage individuals to make contact and build future networks with the aim of developing joint projects.

}, issn = {1176-5283}, author = {Pleasants AB} } @conference {41432, title = {Calculating animal performance from limited liveweight measurements of the population}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {173-175}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {We consider the problem of estimating the distribution of carcass weights in a flock of animals from estimates made on a truncated sample. This arises when a farmer chooses the heaviest lambs for slaughter and then measurements are made by the meat processor. This enables a farmer to answer two questions: what proportion of the animals remaining exceed a nominated carcass weight, and/or what carcass weight is exceeded by a nominated proportion of the population? Estimates of these statistics and their uncertainties are derived and are exact if the animal weights are normally distributed. These calculations can be the basis of decisions about future feeding and drafting strategies, important for farmers producing animals on contracts for future delivery. An example is given based on 1000 lambs using a cut-off weight of 15.5 kg with mean of this upper group of 16 kg. Using a realistic estimate of a standard deviation (of the weighing scales) of 0.3 kg, this gives an estimated mean of 14.6{\textpm} 0.04 kg, with a standard deviation of 0.94{\textpm}0.044 kg, and that 75\% of the lambs in the population exceed 13.9{\textpm}0.07 kg. The proportion of lambs that exceed 14.5 kg is then between 51.3\% and 55.7\%. }, issn = {1176-5283}, author = {Wake GC and Pleasants AB} } @conference {41295, title = {Modelling the impact of nutrition and genotype on lactation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {61}, year = {2001}, month = {Jan}, pages = {237-238}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Dairy cows grazed on pasture experience variation in their nutritional status during lactation, as both pasture quality and availability vary seasonally. This has both immediate and long-term consequences on cow performance. Acute effects of nutrition are related to availability of nutrients for milk secretion, and are manifested in day-to-day variation in milk yields. Of further importance are the chronic effects of nutrition, which act on the development of the mammary gland, impacting on the persistency of lactation. Typically, cows in a New Zealand, pasture-grazing environment exhibit a decline in milk yield of around 10\% per month, after peak lactation, whereas cows fed a concentrate diet in Northern Hemisphere systems show declines of less than 4\%. Post-peak declines in milk yield are associated with a proportional and permanent decline in the number of secretory cells in the udder, and this decline is modulated by nutrition (Davis et al., 2000). Quantifying the milk-yield response of a cow to different nutritional regimes is useful from a breeding and selection point of view, but on its own does not give insight into which pathways are likely to be affected by nutrition, nor does it explain the origin of differences in responses between cows. To this end, mechanistic mathematical models that reflect the underlying biology of the udder are particularly useful. }, issn = {1176-5283}, author = {Davis SR and Vetharaniam I and Upsdell M and Kolver ES and Pleasants AB} } @conference {41140, title = {A Dynamical Model of Body Composition in Sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {275-278}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A dynamical model describing the evolution of muscle, viscera and fat in response to different levels of energy intake over time in sheep is presented. The model shows responses consistent with observations of compensatory growth in sheep and cattle over a range of energy intake levels. Model parameters are derived from data measured by Ferrell et al., (1986) to investigate compensatory growth in lambs. The model is shown to generally reproduce the behaviour of the muscle, viscera and fat components of the lambs in this trial. The utility of the model for designing optimal nutritional management strategies for raising animals for slaughter is discussed, as well as the potential of the model to advance the understanding of animal nutrition by investigating different functional forms for relationships such as maintenance requirements. }, issn = {1176-5283}, author = {Soboleva TK and Oddy VH and Pleasants AB and Oltjen JW and Ball AJ and McCall DG} } @conference {41112, title = {The Evolution of Liveweight Variance in Angus Steers and Strategies for Control.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {59}, year = {1999}, month = {Jan}, pages = {173-176}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effect of year of birth and nutritional treatment on liveweight variance in mobs of Angus steers from birth until approximately 30 months-of-age is examined. Significant (P<0.01) differences in liveweight variance at 30 months-of-age were recorded between years. The environment of the calves over the first 20 days of life appeared to affect the development of mob variance, steers which experienced early life on a sawdust pad showing higher variance at 30 months-of-age in liveweight and carcass weight. Restricted nutrition during the first winter of the steer{\textquoteleft}s life was associated with a significantly (P<0.05) higher variance in 30 month liveweight (standard deviation 24.0 v 37.8kg). Within mob, lower rates of liveweight change were associated with an increase in liveweight variance (r = -0.72). A mathematical model was used to assess the effects of controlled mating strategies on mob variance. Minor improvements were possible. The implications of controlling mob variance for farm quality assurance management is discussed. }, issn = {1176-5283}, author = {Pleasants AB and McMillan WH and Barton RA} } @conference {41043, title = {Growth and carcass composition of Angus steers raised together from birth and managed on two post-weaning nutritional}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {252-255}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two groups of 33 Angus steers aged 270 days and weighing 179 {\textpm} 2.1 kg were allocated after weaning to 2 pasture regimes designed for high (H) and low (L) mean Liveweight. When the treatments finished after 138 days liveweights were 242 {\textpm} 3.7 kg (H) and 218 {\textpm} 3.7 kg (L). Both H and L groups were then grazed together on pasture until slaughter at 30 months of age. At slaughter fat depth at the 12th rib, weight of kidney and channel fat, ribeye area, and the trimmed fat, bone and lean (90\% visual lean) were measured from the right side of the carcass. Carcass weight was the same for both treatment groups (258 {\textpm} 2.5 kg). The L group had faster liveweight gain than the H group for 283 days after treatment, but not thereafter. Steers from the L treatment had more kidney and channel fat (P<0.02). A significant (P<0.01) regression coefficient of 0.05 {\textpm} 0.019 for carcass weight on kidney and channel fat weight existed for steers in the H group, but not the L group. Rate of live weight gain before weaning was significantly (P<0.01) related to the weight of trimmed bone and lean at slaughter. Differences between animals in live weight gain at the end of the treatment period affected the weight of kidney and channel fat in the L group (P<0.01), and the weight of trimmed fat in the L group (P<0.05). These results are discussed in context of effects of growth rate on tissue development in cattle. }, issn = {1176-5283}, author = {Pleasants AB and Barton RA and Ball AJ and Oddy VH} } @conference {40629, title = {Nutritional buffering: Do we make the best use of this phenomena in the breeding cow}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {329-332}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The nutritional buffering capacity of the beef cow, defined as the ability to absorb low levels of feeding without compromising productivity, is reviewed in regard to winter management. It is shown that resistance to liveweight loss is repeatable for cows within the same herd between years (correlations 0.4 to 0.8, P<0.01). However this capacity is associated with lower calf weaning weight (correlations 0.3 to 0.5, P<0.05). There was no association between the amount of winter liveweight loss and cow liveweight, calf birth weight or time to first oestrus in the cow. It is shown that these results are consistent with evidence for the variation of maintenance requirements between cows. It is suggested that the buffering capacity of the beef cow could be exploited through animal breeding or by management of early nutrition. There may be no one cow type which is optimal for all farming situations, and instead a range of cow types which are more or less able to buffer feed shortages may be preferred. }, issn = {1176-5283}, author = {Pleasants AB and Barton RA and McCall DG} } @conference {40646, title = {The role of systems research in animal science}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {417-422}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {This paper presents challenges to the way we conduct experimentation in animal science. The theme of the paper is to show the benefits of using systems research methods in both our basic and applied animal science. The need for more accurate prediction of biological processes to achieve future breakthroughs in animal production is postulated. The use of systems research using dynamical systems models in our basic science to better understand and predict the outcome of complex biological processes is discussed. In the applied science context, difficulties in translating basic (component) research results into recommendations for improved farm performance are emphasised. Equally, difficulties in designing interpretable farm system experiments are acknowledged. Finally, examples are given of the benefits of using whole farm models to integrate component results and create a link between component research and improved farm system, field, experimental approaches. }, issn = {1176-5283}, author = {McCall DG and Sheath GW and Pleasants AB} } @conference {40533, title = {Fat colour and meat colour in different breeds of steers in five consecutive years raised on pasture and slaughtered at 30 months of age}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {389-392}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Three experiments were carried out to determine the effects of short term nutritional changes, stress and changes in carotene content of the diet on plasma carotene concentrations (PCC) and the relative ranking of the cattle for PCC. None of the treatments affected the ranking of the cattle for PCC even though the changes in dietary carotene intake caused large changes in mean PCC.}, issn = {1176-5283}, author = {Barton RA and Pleasants AB} } @conference {40532, title = {Prediction in animal production models based on the allometric hypothesis when the size variable is random}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {385-388}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Pleasants AB and Wake GC and Rae AL} } @conference {40438, title = {Precalving nutrition of heavy two year old Angus heifers weighing 415 kg at calving}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {303-306}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A short term grazing trial was conducted on a central Taranaki dairy farm to study the effects on milk production of regular light dressings of nitrogen fertiliser (N), when compared to a single heavy application. Fifteen paddocks were allocated to each of two treatments. Both treatments consisted of 50 kg N/ha applied as either a single heavy application (50 kg N/ha) on 10 September (50x1 treatment), or frequent light applications (10 kg N/ha), applied progressively from 10 September directly after the following 5 grazings (10x5 treatments). Grazing of herd alternated between the two treatments with 6 paddocks of one treatment being grazed for 4 consecutive days. Total milksolids (MS) production data was obtained for days 3 and 4 of each grazing period. Total net herbage accumulation from August to mid-January was similar for the two treatments even though there was a difference in the pattern of accumulation. The 50x1 treatment resulted in 28\% higher net herbage accumulation between 12 November and 11 January. Botanical composition of the pastures in September, November and December indicated that 50x1 treatment increased the ryegrass content in November. Total MS production was 400 kg MS/ha between 1 October and 10 January for both treatments. The monthly MS production differences between the treatments were small. The results show there to be no advantage in terms of MS production to light regular applications of nitrogen fertiliser when compared to a single heavy application.}, issn = {1176-5283}, author = {Pleasants AB and Barton RA} } @conference {40359, title = {Optimization of {\textquoteright}herd-in-calf rate{\textquoteright} with respect to the length of the postpartum anoestrous period in Angus cows suckling calves}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {459-464}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A trial was undertaken to evaluate the effectiveness of the CIDR-B in buffalo. Twenty four, 20 month old buffalo heifers had CIDR{\textquoteright}s inserted (day 0) for 12 days. Each heifer was injected intramuscularly with 10 mg of oestradiol benzoate at CIDR insertion and 150 IU of PMSG at CIDR removal. Two buffalo bulls fitted with chin ball harnesses were introduced into each of 2 groups of 12 heifers. Continuous observations of mating activity commenced 24 hours after CIDR withdrawal. The heifers were bled for progesterone analysis on days -20, -9, 0, 2, 7, 12 and 26.9 CIDR{\textquoteright}s (38\%) lost from the heifers were replaced immediately after the losses were noticed. The mean interval from CIDR removal to onset of mating activity was 50.3}, issn = {1176-5283}, author = {Pleasants AB and Barton RA and Morris ST and Anderson WJ} } @conference {39470, title = {Onset of puberty in Angus, Friesian, Friesian x Angus, and Friesian x Jersey heifers}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {35}, year = {1975}, month = {Jan}, pages = {97-102}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Pleasants AB and Hight GK and Barton RA} }