Search

The objective of this study was to estimate the genetic parameters for age at first calving in Charolais and Limousine cattle breeds using animal model. The reproduction traits are influenced by genetic factors and environmental factors. The genetic factors are breed, individual and environmental factors are: climate condition and nutrition. The data consisted on 239 records for Charolais breed and 309 records for age at the first calving for Limousine breed. The data were from Romanian Breeding Association for Beef cattle. The age at the first calving was 792.92±6.77 days for Charolais breed and 813.83±6.09 days for Limousine breed. The heritability value for age at the first calving was 0.273 for Charolais and for Limousine breed was 0.275. The breeding values of cows with records for age at first calving were between −30.697 and 40.929 for Limousine breed were between −46.64 and 42.65. For improvement the reproduction traits it is necessary to improve the environmental conditions and supervision of reproduction activity in the farms and the selection of the best cows. The selection based on the breeding values of the cows determined the improvement of age at first calving. Improvement the reproduction traits increase the profitability of farms. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the genetic parameters for reproductive traits in Romanian Spotted, Simmental type cattle breed using animal model. The data of reproduction traits were from Romanian Breeding Association Romanian Spotted, Simmental type. The age at the first calving was 889.82±2.79 days and first calving interval was 391.55±2.08. The heritability value for age at the first calving was 0.25 and for calving interval was 0.14. The breeding values of cows with records for age at first calving were between -77.52 and 62.60 and for first calving interval between -31.149 and 44.55. Improvement the reproduction traits increase the profitability of farms. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the breeding value and heritability for calving score using an animal model for population from Aberdeen Angus breed. Data consisted of records of 1297 calves of Aberdeen Angus breed from Aberdeen Angus Association Romania. The mean for calving score was 1.007±0.002. The breeding values for calving score for calves were between -0.013 and 0.075. The heritability for calving score was low 0.08 in Aberdeen Angus breed. The animal model was adequate due it is simpler than threshold model for calculate the genetic parameters for calving score. [ABSTRACT FROM AUTHOR]

The aim of study was the estimation of the genetic parameters of somatic cell score of Romanian Black and White cattle population. Test-day records of somatic cell count (SCC) of 305 days lactation were from Romanian Black and White cattle population from experimental farm of our institute. The mean of somatic cell count of milk in the first lactation of Romanian Black and White cows was 291966.89. The genetic parameters were estimates with random regression test-day animal model. The heritability for somatic cell score (SCS) ranged from 0.0473 to 0.147. The breeding values for the best cows for somatic cell score were between -35.566 and -191.358. The genetic correlations between somatic cell count milk records test-day were positive. The phenotypic and genetic correlations between somatic cell count and milk yield were negative. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the classical animal model (based on total milk for 305 days) with the Test-Day model (using monthly records of milk yield from Official Records of Performances). The data set derived from a total 175 animals (cows with records, parents of these animals and the descendants) from two Romanian breeds (Romanian Black Spotted and Montbeliarde), the phenotypic and the pedigree information arisen from National Research Development Institute for Animal Biology and Nutrition (IBNA-Balotesti). The selection criteria to be included in the analysis for each cow was to have at least 3 test-days and the days in milk between 200 and 330 for the Test-Day model and the total amount of the 305- day lactation yield for classical Animal Model respectively. Both models use B.L.U.P methodology and for that reason all the estimates were adjusted for fixed effects and all the breeding values and the solution for fixed effects were estimated simultaneous. For the animal model the fixed effects used was the breed and the year of performing and for the Test-Day model was an extra one, the test day effect. The correlation calculated between test days was very high (over 90%) for consecutive tests, and was getting lower when the days between tests was higher (under 40%). Also, in terms of heritability the values were in normal limits throughout lactation, except at the beginning and end of lactation period where these values were a little bit higher. The comparison of the ranking of breeding values with Spearman rank correlation shows that in 80% of the cases the ranking was similar for both models. As the ranking correlations shows, it is certain that the two models are very similar when they are used for genetic evaluation. But, in conclusion, we can say that for a better lactation curve estimation it is recommending to use test-day model for dairy cattle. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse methodology of genetic parameters estimation and breeding value prediction for milk, fat and protein yield in the first lactation of Holstein cattle using Best Linear Unbiased Prediction procedure- Restricted Maximum Likelihood method with individual animal model. The cows with records in first lactation were from experimental farm of National Research-Development Institute for Animal Biology and Nutrition Balotesti. The genetic parameters were estimated with Restricted Maximum Likelihood method using Individual Animal Model. The estimated heritabilities were 0.249 for milk yield, 0.339 for fat yield and 0.315 for protein yield. The data were analysed with R software. The breeding values of the best Holstein cows for milk yield ranged from 21.13 to 176.97 l, for fat yield ranged from 5.178 to 35.34 kg and for protein yield ranged from 5.516 to 25.155 kg. [ABSTRACT FROM AUTHOR]

The aim of this paper is to compare four methods for estimating the breeding value of sheep, for the milk production. The research was conducted at the National Institute of Research and Development for Biology and Animal Nutrition Balotesti, Ilfov. The biological material is represented by a flock of Palas Milk line, consisting of 805 animals: 344 downward, 121 rams and 340 sheep. The character analyzed was the amount of milk in the weaning lamb period to the end of the lactation. Lactation length was between 51 and 230 days. To estimate heritability (h2) and breeding value, BLUP methodology applied to an animal model was used. The heritability value was estimated by the method of single factor analysis of variance, and was 0.73. By the animal model, the heritability was stabilized at 19 1iterations, the value being 0.235. The breeding value was estimated in four ways: a) Performance (PP); b) Average performance of paternal half-sisters (PSS); c) LUSHIndex(IL); d) Individual Animal model (IAM). The best work option was comparatively analyzed through Spearman rank correlation and selection accuracy. The highest rank correlation was obtained with the combination IL -IAM, 0.82 respectively, due to the fact that the methods used commonly a high sources and amount of information. The opposite is the combination of IAM-PSS, where rank correlation is -0.0071. In terms of selection accuracy, the highest value was recorded for the IAM (0.52) and the lowest inbreeding value estimation based on PP (0.48), which indicates a superiority of IAM of 8.33%. In conclusion, to achieve a more precise evaluation of animal breeding, all available sources of information should be use in calculations. Also, the combination of these sources is recommended to be performed by using BLUP methodology, applied to an animal model. [ABSTRACT FROM AUTHOR]