• Asian-Australasian Journal of Animal Sciences
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• 제5권2호
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• pp.309-314
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• 1992

A review of dairy development and crossbreeding programmes in Malaysia since 1953 is undertaken, based on the relevant literature and the writer's experience. The need for higher domestic milk production and the role of crossbreeding in the realization of this objective is explained. A retrospective evaluation is made of the past crossbreeding programmes and of the decision to use temperate dairy breeds for the purpose. Current dairy development under the 'New Economic Policy' of the Malaysian government and the major problems connected with the importation of high-milk producing animals are discussed. To overcome existing constraints, future strategies for crossbreeding and dairy development, based on long-term objectives, are proposed. It is concluded that crossbreeding will only be useful if the introduction of high yielding dairy animals is combined with an improvement of existing husbandry systems.

• Asian-Australasian Journal of Animal Sciences
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• 제10권6호
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• pp.621-628
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• 1997

This study aimed to quantify the impact of crossbreeding at farm level, in mixed farm systems in Gujarat. Households with crossbred cattle did not differ from households without crossbreds in terms of farm resources, crop gross margins and off-farm income. The use of crossbred animals did increase livestock gross margins by 64% and household income by 22%. The three agro-ecological zones included in this study differed considerably according to farm system and household income. However, in all three zones, households with crossbreds had higher livestock gross margins than households without crossbreds. There was no real difference in work load and labour division between households with and without crossbreds. There was also no difference in the use of bullocks for draught purposes between the two types of households. In particular buffaloes are being replaced by crossbred cattle. There was a large variation in farm income, largely because of land area. The milk offake per average cow and the number of buffaloes also related positively to farm income in both types of households. Crossbreeding has proved technically and financially viable in different Gujarat mixed farming systems. It can be concluded that crossbreeding is an important development option for landless farmers.

• Asian-Australasian Journal of Animal Sciences
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• 제15권2호
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• pp.166-171
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• 2002

The main objective of the present study is to estimate the crossbreeding parameters in respect to serum lysozyme level in broilers. The experiment involved a complete $4{\times}4$ diallel design using four synthetic broiler lines namely Coloured Synthetic Male Line (CSML), White Synthetic Male Line (WSML), Coloured Synthetic Female Line (CSFL) and Naked Neck Line (NNL). The lyophilised Micrococcus lysodeikticus suspension was used to detect the lysozyme level in the serum of birds. The data were analysed by least-squares method to find the effects of genetic and non-genetic factors using appropriate model. The crossbreeding parameters for this trait were estimated by complete diallel model assuming the effect of each synthetic line as fixed. The results indicated that additive and non-additive genetic variation attributed to minor genes at many loci is important for the genetic control of serum lysozyme level in chickens. Total non-additive components of variance also showed significant amount of heterosis in crossbred progenies, and therefore exploitation of non-additive component of variance is possible for improvement in serum lysozyme level in broilers. The overall results suggested that for commercial broiler production system, the selection for specialised line on the basis of serum lysozyme level and subsequent crossing of parent lines could enhance the immunocompetence status in relation to serum lysozyme level in crossbred chickens.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.1019-1025
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• 2014

This study was conducted to observe the effects of crossbreeding and gender on the carcass traits and meat quality of Korean Native Black Pig (KNP) and $KNP{\times}Duroc$ crossbred ($KNP{\times}D$). A total of 50 pigs comprising seven KNP barrows, eight KNP gilts, twenty $KNP{\times}D$ barrows and fifteen $KNP{\times}D$ gilts were used in this study. Animals were reared in the same housing condition with same feed diet for six months prior to slaughter. After an overnight chilling, the carcasses were graded, and samples of Musculus longissimus dorsi were obtained for meat quality analysis. The slaughter and carcass weights and dressing percentage of $KNP{\times}D$ were higher (p<0.001) than those of KNP. The slaughter and carcass weights and backfat thickness of barrows were higher (p<0.01) than those of gilts. There were no significant difference in carcass conformation and quality grade between KNP and $KNP{\times}D$ as well as barrow and gilt. Fat content of $KNP{\times}D$ was higher (p<0.001) than that of KNP. Fat content of barrow was higher (p<0.001) than that of gilt. There was interaction between crossbreeding and gender on the fat content. KNP gilt showed higher fat content than KNP barrow whereas $KNP{\times}D$ barrow showed higher fat content than $KNP{\times}D$ gilt. Lightness, redness, yellowness, chroma and hue angle values and color preference of meat of $KNP{\times}D$ were lower (p<0.001) than those of KNP. Redness, yellowness and chroma values of meat of barrow were lower (p<0.05) than those of gilt. It is concluded that crossbreeding KNP with Duroc increases carcass productivity and meat fat but decreases meat color values and preference. Crossbreeding of KNP with Duroc produces a better fat deposition in meat of barrows than in gilts.

• Asian-Australasian Journal of Animal Sciences
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• 제19권11호
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• pp.1536-1540
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• 2006

Crossbreeding effects for wool quality traits viz. greasy fleece weight (kg), staple length (cm), average fibre diameter (${\mu}$) and medulation percentage were estimated using the Dickerson's and Kinghorn's models. The data analyzed involved 15 genetic groups including Nali purebred, $F_1$'s of two and three breeds, $F_2$'s and reciprocal crossbred obtained from the crossing of Nali (N), Merino (M) and Corriedale (C) breeds during 1980-96. Nali and Corriedale breeds had non-significant negative additive genetic effects (Dickerson's model) on greasy fleece weight, while effects of Corriedale were negative for staple length only from both models. In general additive genetic effects of all three breeds were non-significant for all the wool traits except medulation percentage. Non significant heterotic and recombination effects (epistatic loss) were estimated from both models. However, the estimates of crossbreeding effects varied between the models both in magnitude as well as in direction barring few exceptions. Undesirable positive heterosis was found on medulation percentage for all types of combinations involving three breeds. Comparison of least squares means of various genetic groups revealed that both two breed and three breed crosses were superior to the Nali breed for all wool quality traits. Fibre diameter of MN crossbreds was significantly less than CN crossbreds. Results also indicated that as the inheritance of Nali breed in a cross is decreased, the medulation percentage decreases which is desirable. Inter se mating of crossbreds (two breed, three breed) has not resulted in a decline in the wool quality traits. These results indicate that the synthetic population derived from three breeds can be stabilized easily for wool traits as there may not be epistatic loss on subsequent inter se mating of crossbreds.

• Asian-Australasian Journal of Animal Sciences
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• 제8권3호
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• pp.295-300
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• 1995

Data from purebred and crossbred cattle involving Holstein and the Local breed in Bangladesh were used to estimate the genetic effects on average daily milk yield and birth weight A total of 877 records on average daily milk yield for 4 types of breed groups and a total of 418 records on birth weight for 5 breed groups were analyzed. Two different methods were applied in this study; the least squares analysis of variance approach and the linear regression approach. Breed group effects were highly significant for both average daily milk yield and birth weight. The result showed that straightbred Holstein produced the highest milk yield and the 7/8 crosses ranked highest in birth weight For the two traits, the additive breed effect was highly significant, whereas the individual heterosis effect was not significant. Furthermore, this study showed a negative maternal heterosis for average daily milk yields and a positive maternal heterosis for birth weight Comparing the breed least squares means obtained from the linear regression approach revealed that straightbred Holstein produced the highest average milk yield and the 3/4 crosses were predicted to have the largest birth weight. It is indicated that the linear regression approach can adequately separate the genetic component of performance, estimate unknown crossbreeding parameters and predict unknown performance of crosses which are not include in the original data.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.428-434
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• 1997

The effect of genetic diversity in sub-populations on breeding efficiency was examined with prospect of potential crossbreeding. Simulation study of selection was performed for 20 generations with 20 replications each, comparing average breeding values and inbreeding coefficients between the two breeding systemes; single population scheme and two population scheme. The different genetic levels were assumed to be caused by different gene frequencies. Phenotypes of two traits generated polygenic effect with additive 36 loci and residuals distributed normally were selected by selection index procedure. High genetic gain with less inbreeding was clearly recognized in the single population scheme, independently of difference in genetic level, economic weight and genetic correlation. Genetic correlation after selection in the single population scheme was lower than the two population scheme. When crossbreeding between the sub-population was taken into account, superiority of the two population scheme was suggested under those restrictions; difference in genetic level is moderate, selection criterion for the two traits is not far from even economic weight, and genetic correlation is positive with low to moderate value. The use of complementarity increased the possibility of the two population scheme.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.422-427
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• 1997

Breeding efficiency was investigated to reveal crucial factors for constructing effective breeding system with subdivided populations under equal genetic level. Simulation study of selection experiment was performed for 20 generations with 20 replications each, comparing average breeding values and inbreeding coefficients between the two breeding systems; single population scheme and two population scheme, each of which had the same genetic parameters. Genetic correlations (-0.5 to 0.5) were assumed to be caused only by pleiotropic effect of a gene. Phenotypes of the two traits generated by polygenic effect with additive 36 loci and residuals distributed normally were selected by two traits selection index procedure. Comparing between the single population scheme and the two population scheme, the single population scheme showed higher genetic gain with lower inbreeding coefficient. This result was confirmed particularly for the situation of high selection intensity, high heritability and high degree of unevenness for economic weight. Genetic correlations in the single population scheme were significantly lower than the two population scheme when initial genetic correlation was negative. When terminal crossbreeding for the two population scheme is taken into account, superiority of the two population scheme was suggested. The terminal crossbreeding was effective under the situation of long term selection, existence of moderate inbreeding depression and use of less extreme economic weight.

• 한국가금학회지
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• 제50권4호
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• pp.213-229
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• 2023

본 연구는 한국 토종닭을 대상으로 부리 다듬기 여부와 교배조합이 생산능력 및 스트레스 반응 정도에 미치는 영향을 살펴 보고자 한 것이다. 시험은 6개의 토종닭 교배조합 248수를 대상으로 부리 다듬기를 실시한 그룹과 하지 않은 그룹으로 나누고, 이들의 생존율, 체중, 산란율, 난질, 깃털 손상도, HSP-70 유전자 발현량, H/L ratio 및 세포 내 DNA 손상률을 조사하여 비교 분석하였다. 분석 결과, 부리 다듬기를 한 그룹이 하지 않은 그룹보다 생존율 및 산란지수는 유의하게 높았고, 깃털 손상도 및 DNA 손상률은 유의하게 낮았다(P<0.05). 반면 육성기 이후 체중, 일계산란율, 난질, HSP-70 유전자 발현율 및 H/L ratio는 부리 다듬기 여부에 따른 차이가 없는 것으로 나타났다. 한편, 교배조합 간에는 생존율, 체중, 깃털 손상도, 난질 및 DNA 손상률에 유의한 차이를 보이고(P<0.05), 산란율, HSP-70 유전자 발현율 및 H/L ratio의 차이는 없는 것으로 나타났다. 생존율, 깃털 손상도 및 DNA 손상률은 부리 다듬기와 교배조합 간의 상호작용이 있는 것으로 나타났다. 이상의 분석 결과로부터 토종닭의 부리 다듬기가 생산능력에 긍정적인 영향을 미치고, 스트레스 반응 정도에 있어서 육성기 이후부터는 부리 다듬기가 스트레스 요인으로 작용하지 않거나, 오히려 스트레스감소 요인으로 작용하는 것으로 판단된다. 또한 토종닭 교배조합 간에 생산능력 및 스트레스 반응 정도의 차이는 있으나 조합별 부리 다듬기가 이들에 미치는 영향은 거의 비슷한 것으로 보인다.

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1152-1161
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• 1999

Buffalo raising to produce milk, meat, and draught power as well as other products continues to be important in Asia and other parts of the world in the next century due to an increase in the demand for such products and the unique roles of buffaloes in rural economy. Long-term breeding strategies with special relevance to present and future farming systems prevailing in developing countries are proposed. Some important considerations in the choice of certain breeding strategies for long-term genetic improvement in buffaloes are discussed. Some recent research results in genetic selection and crossbreeding of buffaloes are highlighted. A review of genetic inheritance of buffalo traits is presented as well as a discussion Of certain quality traits of buffaloes which deserve future research for improvement.