@conference {3672, title = {2015 NZSAP Living Legend Address {\textendash} Invermay Agricultural Centre}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {75}, year = {2015}, month = {07/2015}, pages = {149}, address = {Dunedin}, abstract = {Some of the best science is done by those who are excited by their research and by working with industry. Many breakthroughs come from people noticing, and following up on, unusual observations or anomalies. Often, their passions are funded {\textquotedblleft}from the back pocket{\textquotedblright} for several years; until sufficient information is secured to justify a formal funding application. The Living Legend Lecture invites distinguished longterm members of NZSAP to make a scholarly presentation at the Society{\textquoteright}s annual conference in recognition of their contribution to New Zealand Animal Production over a substantial period of time. Heeding the Guidelines recommendation to consider members resident in the area holding the conference, the 2015 organising committee chose to nominate the contributions of the scientists and technical staff of an iconic Institution, rather than acknowledge a single individual{\textquoteright}s work. No specific animal production {\textquotedblleft}theme{\textquotedblright} was selected. Instead, it was decided to highlight the contribution of the Invermay Agricultural Centre as a whole...}, issn = {1176-5283}, author = {Shackell GH and Drew KR and Fennessy PF and Allison AJ and McEwan JC and Crawford AM} } @conference {89238, title = {Ewe body condition score and the effect on lamb growth rate}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {73}, year = {2013}, month = {Jan}, pages = {131-135}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {

Data were analysed to investigate the association between ewe body condition score (BCS) and lamb growth rate (LGR). Ewe BCS was assessed on a scale of 1 to 5 pre-lambing (BCSL) and at weaning (BCSW). Change in BCS throughout lamb rearing (BCSChange) was calculated as the difference between BCS at weaning and pre-lamb. The three way interaction between birth rank, BCSL and BCSChange was significant (P \<0.05). When the interaction was examined for birth rank, it was significant between BCSL and BCSChange in singles (P \<0.05) and twins (P \<0.01), but not in triplets. In singles and twins, lambs with the highest LGR were from dams that had high BSCL and negative BCSChange or those with low BCSL and positive BCSChange. Triplets had a similar trend whereby lambs with the highest LGR were from dams with a high BCSL and a negative BCSChange. This study suggests that if farmers manage their ewes to achieve a high BCS at lambing time this is likely to improve lamb growth to weaning. In addition, identifying ewes with a low BCS at lambing and preferentially feeding them to increase BCS during rearing may increase single and twinlamb growth rates.

}, issn = {1176-5283}, author = {Mathias-Davis HC and Shackell GH and Greer GJ and Bryant AL and Everett-Hincks JM} } @conference {75875, title = {The association of ewe body condition score with weight of lamb weaned}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {62-65}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {Data from 1,301 ewes lambing in 2009 were analysed to investigate the association of body condition score (BCS) with total lamb weaned (TLW). BCS was assessed on a scale of 0-5 at mating (BCSM), scanning (BCSS), pre-lambing (BCSL) and weaning (BCSW) and categorized as <3, 3-3.5 and >3.5. Ewe age, flock, live weight at mating (LWM) and date of lambing (DOB) had significant effects on TLW (P <0.05). Ewes having triplets at birth with >3.5 and 3-3.5 BCSM had a higher TLW (63.2, 63.0 kg respectively; P<0.05) than ewes with triplets at birth and <3 BCSM (56.1 kg). Ewes with 3-3.5 BCSS had higher TLW than ewes with >3.5 BCSS for all birth ranks (49.8 kg, 47.2 kg respectively, P <0.05). There was no association between BCSL and TLW. Ewes with <3 or 3-3.5 BCSW had a significantly higher TLW than ewes with >3.5 BCSW (>3.5 = 43.8 kg, 3-3.5 = 48.9 kg, <3 = 50.9 kg; P <0.001). This study indicates ewes with 3-3.5 BCSS or <3 or 3-3.5 BCSW outperform ewes with >3.5 BCSS or >3.5 BCSW.}, issn = {1176-5283}, author = {Mathias-Davis HC and Shackell GH and Greer GJ and Everett-Hincks JM} } @conference {60981, title = {A simulation model to partition ewe efficiency into component traits for genetic analysis}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {223-227}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Ewe efficiency is extremely topical in the New Zealand sheep industry. This paper describes a stochastic simulation model which facilitates partitioning of a defined ewe efficiency equation into its component genetic traits. It accounts for, and simplifies, the complex and sometimes unfavorable interactions among components of ewe efficiency. The model tracks simulated genetic effects, inherited from the ewe{\textquoteright}s sires, in breeding ewes and their lambs for key performance recorded traits. The traits simulated are weaning weight, mature weight, number of lambs born, lamb survival, and longevity. Ewe efficiency is defined as the difference between value of lambs weaned and ewe and lamb costs, rather than as a ratio. Output value in NZ$ for the efficiency equation is computed on a ewe by ewe basis, as a function of number of lambs born, lamb survival and weight of lamb weaned, with each of these components partly influenced by one or more genetic effects inherited from simulated sires of the breeding ewes. Preliminary results from the model have identified litter size, ewe longevity, maternal lamb survival, and maternal weaning weight as being important drivers of ewe efficiency. The relative balance of their importance is influenced by farm production levels and environment. }, issn = {1176-5283}, author = {Sise JA and Shackell GH and Byrne TJ and Glennie SF and Amer PR} } @conference {42048, title = {Artificial insemination success rates for Meat and Wool New Zealand central progeny test sires}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {68}, year = {2008}, month = {Jan}, pages = {77-78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Brisbane, Australia}, abstract = {National progeny testing schemes have become important components of national sheep genetic improvement programmes in Australia, France, and New Zealand (Fogarty et al., 2002; Bib{\'e} et al., 2002; Campbell et al., 2005). In 2001 the Alliance Central Progeny Test was established, this was combined in 2005 with the Elite Lamb Progeny Test to become the Meat and Wool New Zealand Central Progeny Test (CPT). Over the past six seasons, a total of 120 leading industry sires, comprising 14 different breeds, have been mated via artificial insemination. CPT rams are genetically connected via common sires ...Continued }, issn = {1176-5283}, author = {McLean NJ and Dodds KG and Knowler KJ and Jopson NB and Behrent M and Logan CM and Muir PD and Shackell GH and McEwan JC} } @conference {41548, title = {Software for evaluating sampling strategies and error rates in the identification of mixed meat products}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {102-106}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {DNA verification of the origin of meat within traceability systems involves the comparison of DNA samples taken at a reference stage with samples taken further down the supply chain. While such verification is well established when whole cuts of meat are involved, this is not the case for mixed-meat products made from an unknown number of contributing animals. Spreadsheet based software has been developed to analyse one DNA verification scheme for determining whether a returned product did indeed originate from a particular manufacturing batch. The scheme involves the comparison of k individual DNA samples (comprising an unknown number of individuals) from the product, with a set of s DNA samples (comprising an unknown number of individuals) taken randomly before manufacture of the batch in question. The software gives the error rate for correctly matching the product to the batch, for different sampling rate combinations of the product and at the factory. Key words: DNA verification; mixed meat; traceability; sampling. }, issn = {1176-5283}, author = {Vetharaniam I and Shackell GH} } @conference {41540, title = {Traceability contract session: Introduction}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {74}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {

Food safety issues, especially those associated with animal disease (e.g. BSE in cattle), human health (e.g. salmonellosis), genetic modification and animal welfare are driving consumer pressure for traceability of animal-derived foodstuffs. Several of our trading partners already have in place, or have signalled, expected compliance dates for meat traceability requirements.
This contract session addresses some of the background as to why, and when, New Zealand (NZ) can expect to be required to have traceability procedures in place to ensure continued access to the world{\textquoteleft}s meat and animal derived foodstuffs market. The following 10 papers will also describe examples of what is currently in place or projected to become available for tracing animals on the farm, during transport and through meat processing plants both in NZ and overseas. The mix of speakers has been chosen to encompass legislative, industry and scientific aspects of traceability of meat and meat products.

}, issn = {1176-5283}, author = {Shackell GH} } @conference {41547, title = {Traceability systems in the meat industry}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {97-101}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {New Zealand is reliant upon maintaining export markets for the sale of a significant proportion of its meat and dairy production. Any loss of key overseas markets has significant implications for the national economy. Therefore, we are obliged to meet or stay ahead of market drivers. Increasingly, one of those drivers is product traceability for reasons of consumer confidence. While traceability systems have a relatively short history, they have traditionally been paper and/or electronic based. They are generally managed by parties with a vested interest, and their integrity is difficult to monitor. Animal products have a unique identifier, DNA, that is tamper proof. There are a number of DNA-based traceability systems around the world that are being used in the meat industry. As well as direct tracing of a meat sample back to the animal, and ultimately to the property the animal was raised on, DNA technologies are also being used on-farm for testing meat quality traits and determining the animal{\textquoteright}s pedigree. This paper describes some of the traceability options that are in use within the environment in which New Zealand is competing for trade. KEYWORDS: traceability; meat; DNA. }, issn = {1176-5283}, author = {Shackell GH} } @conference {40864, title = {Factors influencing induced oestrus in the ewe at the start of the breeding season}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {381}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The objectives of this study were to monitor the physiological events associated with decreasing liveweight in Bos indicusheifers and to determine the characteristics which best predicted the onset of nutritional anoestrus. Eleven post-pubertal Brahman heifers received a diet resulting in a liveweight loss of 0.7 kg/day. Changes in ovarian morphology were monitored using daily transrectal ultrasonography. Liveweight was recorded twice weekly. Heifers became anoestrus after 98 {\textpm} 9 days, following a decrease in liveweight of 68.6 {\textpm} 4.9 kg, equivalent to 21.5 {\textpm} 1.5\% of initial weight. At this time, maximum diameters of ovulatory follicles and corpora lutea (CL) had decreased by 16.7 {\textpm} 3.9\% and 23.7 {\textpm} 3.1\%, respectively. Onset of anoestrus was best predicted by liveweight and maximum diameter of CL when expressed as proportions of initial liveweight and size of CL. The percentage decreases in liveweight and maximum diameter of CL to give a 50\% probability of anoestrus were 21.0\% (95\% confidence interval = (17.7, 27.4)) and 23.0\% (16.7, 37.0), respectively.}, issn = {1176-5283}, author = {Fenton LS and Shackell GH and Ramsay ML and Dodds KG and Reid PJ and McLeod BJ} } @conference {40758, title = {We couldn{\textquoteright}t do it without {\textquoteright}em!}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {1-4}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The job I found most difficult during my tenure as President of this Sociery,was writing tomembers whose abstracts had not been accepted for the conference. The irony is, that a term as President carries with it the implicit responsibility of presenting a paper that does nut go through a selection process. Even more ironical is that in 1976, the incumbent President Alan Kirton noted in his annual report to the AGM, the consensus of the management committee was that in future the Presidential address should be an optional rather than an obligatory feature of the conference. }, issn = {1176-5283}, author = {Shackell GH} } @conference {40736, title = {MOET in ultrafine Merinos: An experimental evaluation}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {281-284}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Results of experimental MOET programme in elite ewes selected from within an ultrafine Merino flock are presented. Of the treated ewes, 60\% provided transferable donors with a mean of 16.7 ovulations and 10.4 embryos recovered, 7.8 embryos transferred, 3.9 lambs born and 3.1 lambs weaned per donor ewe. The wool produced by hoggets from this elite embryo transfer group was 0.9 um (P0.01) finer than that from their contemporaries in the ultrafine selection flock and 2.5 um (P0.01) finer than a random Merino control group. The improvement in fibre diameter was better than expected from the selection differentials, but not significantly so. The h2 estimates for liveweight, clean fleece weight, fibre diameter and yield in three flocks of fine woolled Merinos were 0.50, 0.32, 0.39 and 0.58 respectively. The MOET programme was successfully applied to increase the number of progeny from elite ultrafine Merino ewes. }, issn = {1176-5283}, author = {Wuliji T and Aspinall J and Land JTJ and Shackell GH and Dodds KG and Andrews RN and Rogers J} } @conference {40401, title = {Dose-response to a single injection of PMSG in Merino ewes carrying a double copy of the Booroola FecB gene}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {153-156}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Sheep shorn with a cover-comb were compared with conventionally shorn sheep in two experiments. In the first experiment, ewe and lamb performance and some aspects of ewe physiology were measured with 60 Romney ewes which were shorn before lambing. In the second experiment, oxygen consumption by 12 Romney hoggets was measured before and after shearing in calorimeters at 10 C. In the first experiment, herbage intake by ewes in the 3 weeks post- shearing was not affected by shearing method. There were no treatment effects on the liveweight of ewes, birthweight and growth rate of lambs nor on ewe wool production during the 2 months post-shearing. However, on days 1 and 3 after shearing the plasma concentrations of non- esterified fatty acids and of 3- hydroxybutyrate were higher in the ewes shorn with the conventional comb than in those shorn with the cover comb. In the second experiment oxygen consumption was increased immediately after shearing, by 47\% and 25\% in the conventional- and cover-comb sheep respectively. The difference between the two groups, which remained significant until day 12 post-shearing, decreased with time until it disappeared on day 22. The results show that sheep shorn with the cover-comb were significantly more resistant to cold conditions than those shorn with the conventional comb, particularly during the 3 days post-shearing. Use of the cover comb may offer a useful low cost method of reducing the effects of cold conditions after shearing, but its effects on mortality have not been demonstrated. }, issn = {1176-5283}, author = {Shackell GH and Isaacs KL} } @conference {40336, title = {Artificial insemination and synchronised natural breeding in Red deer}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {327-332}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The cold resistance of cashmere wethers in which cashmere had been harvested by shearing the while fleece, or by removal of down only through repeated hand combings, was studied at two ambient temperatures (10 C and 30 C) and two wind speeds (0 and 6 km/hr). Heat production was calculated from oxygen consumption measured over 24 hours, in 8 pairs of goats fed at 1.25 times maintenance level. In shorn goats, heat production increased by 50\% during exposure to 10 C (compared with 30 C) while the corresponding increase for combed goats was only 9\%. The interaction between the effects of the low temperature and the methods of fibre removal was significant (P<0.001). Similarly at 10 C, exposure to a wind of 6km/hr caused a larger increase in heat production in shorn goats than in combed goats; the interaction was significant (P<0.05). The data show clearly that the combed goats were considerably more resistant to cold conditions that the shorn goats. }, issn = {1176-5283}, author = {Fennessy PF and Mackintosh CG and Shackell GH and Whaanga AJ} } @conference {40293, title = {A simplified MOET technique for Merino ewes carrying a double copy of the Booroola FecB gene}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {107-110}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two trials were conducted to determine the effect of different oestrous synchronisation regimens on oestrous behaviour, timing of ovulation and fertility of fallow deer. In Trial 1, 59 mature does were allocated to 6 treatment groups (n+9-10 per group). Does in Groups 1, 2 and 3 each received an i.m. injection of an analogue of prostaglandin F2alpha (PG; 500 ug cloprostenol) on Day 13 of a synchronised oestrous cycle. Animals in Group 2 and 3 also received 50 or 100 IU PMSG respectively at the time of PG administration. Does assigned to Groups 4, 5 and 6 each received an intravaginal CIDR device for 14 days with animals in Group 5 and 6 also receiving 50 or 100 IU PMSG respectively, at the time of CIDR device withdrawal. Incidence of oestrus was higher following treatment with CIDR devices than with PG (29/30 vs 12/29, P<0.001). PMSG induced earlier onset of oestrus (34.6}, issn = {1176-5283}, author = {Shackell GH and Isaacs KL} } @conference {40285, title = {The timing of oestrus, LH surge and ovulation in ewes following synchronisation with MAP sponges FGA sponges or CIDR{\textquoteright}s}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {51}, year = {1991}, month = {Jan}, pages = {73-78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {As part of a programme to increase the number of homozygous (FecB FecB) replacements available in the Booroola Merino flock at the Tara Hills Research Station a MOET technique was utilised. Because ewes of BB genotype are difficult to superovulate, with predictable results, using conventional treatment regimes, a simplified programme aimed at enhancing the natural ovulation rate was used. Thirty eight ewes were treated for 10-11 days with intravaginal sponges. The ewes were then injected with 500 iu of PMSG on day 15 after sponge withdrawal and joined with entire rams for 5 days. Sixty six percent of ewes were marked by the ram and the mean ovulation rate of these was 8.3 (range 5- 18). Embryo recovery rate was 93.4\% following retrograde flushing of the fallopian tubes. Fertilisation rate was 68\% and 5.3 embryos were transferred per donor operated (range 0.-11). The ewes were remated and lambed naturally. By using a combination of MOET and remating, 24 donor ewes produced a mean of 3.3 lambs weaned compared to 1.4 lambs weaned by their naturally mated flock mates. }, issn = {1176-5283}, author = {Shackell GH} } @conference {40253, title = {Factors influencing the success of a large scale artificial insemination programme in sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {427-430}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Two experiments were conducted to compare PMSG injection to GnRH infusion for induction of breeding in anoestrous ewes. In Experiment One, sixteen Suffolk ewes were pre-treated for 14 days with 30 mg Cronolone sponges. At sponge removal half of the ewes received 0.125 ug/hr GnRH for 72 hours via subcutaneous osmotic pumps. The other half received a single injection of 750 iu PMSG. Plasma LH levels gradually increased and were sustained for 24 hours. Estrus, ovulation and corpus luteum function were expressed in half of the ewes treated with GnRH. All ewes treated with PMSG exhibited estrus, ovulated and formed functional corpora lutea. In Experiment Two, 24 ewes were divided into two groups and the same treatments as in Experiment One were applied. Fertile rams were introduced to all the ewes at the time of sponge removal. Estrus was detected in 75\% of the GnRH treated ewes vs 100\% in PMSG treated ewes. Lambing rates were 44\% and 56\% in GnRH and PMSG groups respectively. These results suggest that the induction of fertility using continuous infusion of GnRH is encouraging. However, other GnRH delivery systems should be investigated. }, issn = {1176-5283}, author = {Shackell GH and Kyle B and Littlejohn RP} } @conference {40258, title = {Mating performance of Texel rams}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {453-454}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Romney, Coopworth and Perendale ewes were accidentally exposed to facial eczema before May 1 hogget mating at 9 months of age. Serum gamma-glutamyl transferase (GGT) levels of individual animals were determined on 21 April. The ewes were divided into 3 classes for analysis based on the GGT levels: 1.<100 IU/1;2. 100-350 IU/1; and 3.>350 IU/1. At all matings over 4 years the ewes in class 3 had a lower fertility than class 1. These differences were only significant at the hogget and two-tooth mating. The total number of lambs weaned per ewe mated were class 1-5.0; class 2-4.4; and class 3-4.3 (P<0.1). There were no lifetime effects on fleece weight. }, issn = {1176-5283}, author = {Davis GH and Knight TW and Sorenson E and Shackell GH and Holmes MR and Farquhar PA} } @conference {39760, title = {Ovulation and oestrous responses of high and low fecundity ewes to ingestion of isoflavone-rich pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {42}, year = {1982}, month = {Jan}, pages = {29-32}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Well or poorly reared ewes were differentially fed at 1 of 5 pasture allowances for 6 weeks prior to a synchronised mating. Rearing class and flushing treatment significantly affected ovulation rate. The well and poorly reared ewes had mean multiple ovulation rates per ewe cycling of 39 and 19\% respectively. Fitting pre-flushing and joining weights as covariates removed rearing and differential feeding effects on those rates. Extrapolation of the data suggests that poorly-reared ewes would ovulate similarly to well reared ewes at similar mating weights. Facial eczema depressed live-weight gain and had a further detrimental effect on the probability of ewes ovulating.}, issn = {1176-5283}, author = {Kelly RW and Shackell GH} } @conference {39492, title = {Libido testing and subsequent mating performance in rams}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {35}, year = {1975}, month = {Jan}, pages = {204-211}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Kelly RW and Allison AJ and Shackell GH} }