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Subject: search.filters.subject.Genetic improvement programme

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    A genetic improvement programme for New Zealand dairy goats : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Institute of Veterinary, Animal and Biomedical Sciences (IVABS), Massey University, Palmerston North, New Zealand
    (Massey University, 2014) Solis-Ramirez, Jose
    The establishment of genetic improvement programmes is an important aspect of any modern animal production industry. The New Zealand dairy goat industry has no national genetic improvement programme aimed at improving performance in economically important traits. A survey of dairy goat farmers was undertaken to collect information about their farming systems. Does were kept under indoor conditions and averaged (and standard deviation) of 2.8±0.2 litres of milk per day. Information on herd structure, reason for culling and death, milk-solids concentration and production, cost of production, revenue and management was collected. Four mathematical models were evaluated using random regression models to estimate lactation yields from test-day records. The Wilmink model (WK) was chosen as the best model based on AIC fit statistic. Does which were 75% Saanen and 25% other breeds or Toggenburg produced the highest milk yield (MY), fat yield (FY) and protein yield (PY), while Toggenburg does produced the lowest yields. Information from the survey was used to develop a deterministic bio-economic model to estimate economic values (EVs) for four payment scenarios. The breeding objective included seven traits: MY, FY, PY, lactose yield (LY), liveweight (LW), longevity (LGTY) and Somatic cell score (SCS). For the Current payment system in New Zealand (payment on milk-solids) the EVs were NZ$11.64, NZ$12.27, NZ$12.39, NZ$-0.10, NZ$-2.15, NZ$0.04 and NZ$-8.22, respectively. Heritabilities and repeatabilities were estimated using uni- and bivariate animal model analyses with two random variables (animal for additive genetic component and doe for animal permanent environmental component). Heritabilities for MY, FY and PY were all 0.21 and 0.22 for SCS with similar standard errors. Repeatabilities ranged from 0.40 for MY, FY and PY to 0.49 for SCS. Genetic and phenotypic correlations between milk traits were positive and high, while between milk traits and SCS were from positive low to low negative. These parameters suggest moderate favourable responses to selection for increased milk solids and reduced SCS. Genetic gain and responses in the traits in the breeding objective were estimated for pedigree and progeny testing selection schemes using a selection index for one (MS) or three traits (MY, FY and PY). Results suggested that higher genetic gain and responses in individual traits occurred using a progeny test scheme. The information generated from this research should be applied to the New Zealand dairy goat industry to improve farm profit per milking doe.
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    Examination of alternative selection polices [sic] for sport horse breeding in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University
    (Massey University, 1993) Rogers, Christopher William Warnock
    The present structure for breeding spon horses in New Zealand was summarised. The New Zealand sport horse breeding population probably consists of about 5750 mares mated to 288 stallions. There are approximately 35,000 horses in the total recreation category of which about 4500 are registered for competition use with the New Zealand equestrian federation. Most horses produced will be used locally but there is a lucrative export market. Breeders range from amateurs with 1-2 mares producing mainly for their own use through to professionals with sizeable herds. Some are heavily involved in exponing. At present the industry lacks an effective genetic improvement structure. A high proportion of breeding stock are recruited from the racebred thoroughbred population and are not evaluated for a spon horse objective before entry. If spon horse breeding is to attain its potential a more efficient structure must be developed. A industry objective was identified for the breeding, development, and competition system. Economic weights had to be subjectively derived due to limited industry data. Alternative single stage schemes to generate genetic response in the proposed breeding objective were compared using deterministic models. Benefits and costs were predicted and analysed. The one day field test appeared to generate the most genetic progress and the best benefit-cost result of the single-stage sire-selection models. Station tests lasting 14- 100 days gave good genetic gain although it was assumed that high costs would greatly limit the number of 3 year old colts tested as potential sires in comparison with the one day field test. Selection on data generated in competitions restricted to young horses also generated a good rate of genetic gain. The use of the one day field test to evaluate dams of sires as well as potential s1re candidates offered an 7.7% increase in total genetic response. This model offered the best benefit cost result due to greatest efficiency of genetic improvement but it also offered significant secondary benefits. However further research on other alternatives is desirable before an evaluation programme is firmly established.