Schätzung genetischer Parameter für Testtagsergebnisse von Milchleistungsmerkmalen bei Bunten Deutschen Edelziegen

Abstract

Title of the paper: Estimation of genetic parameters for test day records of milk performance traits in German Improved Fawn The objectives of this study were to estimate genetic parameters for milk performance traits of German Improved Fawn by using univariate und multivariate animal models. The analysis was based on 27,778 test day records of 1,848 German Improved Fawn with 3,574 lactation records distributed over 229 flocks in Lower Saxony, Saxony and Baden-Wuerttemberg. Milk records were sampled between 1988 and 2002. The animals in our analysis were the progeny of 455 sires and 1.148 does. Heritabilities estimated with a multivariate test day model with fixed regression were h² = 0.19, 0.16 and 0.15 for milk, fat and protein yield. For fat and protein content and Somatic Cell Score (SCS) heritabilities were h² = 0.17, 0.14 and 0.16, respectively. The additive genetic correlations between milk yield and fat as well as protein yield of German Improved Fawn were very high and positive (r g = 0.84 and r g = 0.77). Milk yield and milk contents were genetically negative correlated with r g = -0.28 for fat and r g = -0.22 for protein content. A moderate additive genetic correlation (r g = 0.48) between fat and protein content was estimated. There were no considerable additive genetic correlations between fat yield and protein content as well as between fat content and protein yield (r g = 0.05 and r g = 0.09). Additive genetic correlations between milk, fat or protein yield and SCS were high and negative, whereas additive genetic correlations between fat or protein content and SCS were low and positive. The genetic parameters estimated from field test records allow to achieve genetic progress in milk performance traits of German Improved Fawn.

Impact of udder health on economics of dairy goat

“…Probably due to the complexity in health traits the relationship to other traits published in the literature varied from positive to negative e.g. from -0.96 (Bömkes et al, 2004) to 0.12 (Rupp et al, 2011) valid for milk yield and SCC. There are many intrinsic factors (related to animal), extrinsic (considering the management and technology) and others (related to the SCC evaluation in the milk from single samples or form bulk tank milk) which should be taken into account when using the SCC as a tool in the improvement of udder health and the quality of milk in dairy goats (Jimenez-Granado et al, 2014).…”

Genetic control of milk yield from lactations of different duration in Nili-Ravi buffaloes

“…It was concluded that although, genetic correlation between the two trait is high (0.70) and inclusion of lactation length in a selection index with milk yield could improve the selection response slightly (104 vs 103 kg) absence of precise selection weights and complexity of multiple trait model did not justify the use of such a selection index for Nili-Ravi buffaloes. Test-day models are being developed for use in buffaloes like other species (HORSTICK and DISTL, 2002;AMIN, 2003;BÖMKES et al, 2004;HINRICHS et al, 2006) but data formats require drastic changes to incorporate these models for recording and selection of buffaloes, similar to those suggested (SWALVE, 1995) for cattle breeds. Phenotypic trend in lactation milk yield was negative in the present study.…”