Selection Response Due to Different Combination of Antagonistic Milk, Beef, and Morphological Traits in the Alpine Grey Cattle Breed

Abstract

Selection in local dual-purpose breeds requires great carefulness because of the need to preserve peculiar traits and also guarantee the positive genetic progress for milk and beef production to maintain economic competitiveness. A specific breeding plan accounting for milk, beef, and functional traits is required by breeders of the Alpine Grey cattle (AG), a local dual-purpose breed of the Italian Alps. Hereditability and genetic correlations among all traits have been analyzed for this purpose. After that, different selection indexes were proposed to identify the most suitable for this breed. Firstly, a genetic parameters analysis was carried out with different datasets. The milk dataset contained 406,918 test day records of milk, protein, and fat yields and somatic cells (expressed as SCS). The beef dataset included performance test data conducted on 749 young bulls. Average daily gain, in vivo estimated carcass yields, and carcass conformation (SEUROP) were the phenotypes obtained from the performance tests. The morphological dataset included 21 linear type evaluations of 11,320 first party cows. Linear type traits were aggregated through factor analysis and three factors were retained, while head typicality (HT) and rear muscularity (RM) were analyzed as single traits. Heritability estimates (h2) for milk traits ranged from 0.125 to 0.219. Analysis of beef traits showed h2 greater than milk traits, ranging from 0.282 to 0.501. Type traits showed a medium value of h2 ranging from 0.238 to 0.374. Regarding genetic correlation, SCS and milk traits were strongly positively correlated. Milk traits had a negative genetic correlation with the factor accounting for udder conformations (−0.40) and with all performance test traits and RM. These latter traits showed also a negative genetic correlation with udder volume (−0.28). The HT and the factor accounting for rear legs traits were not correlated with milk traits, but negatively correlated with beef traits (−0.32 with RM). We argue that the consequence of these results is that the use of the current selection index, which is mainly focused on milk attitude, will lead to a deterioration of all other traits. In this study, we propose more appropriate selection indexes that account for genetic relationships among traits, including functional traits.

Genome Wide Association Study of Beef Traits in Local Alpine Breed Reveals the Diversity of the Pathways Involved and the Role of Time Stratification

“…As for body weight, ADG presents lower h 2 in first stages of the performance test, and h 2 values agree with what has been found in the literature (Yin and König, 2018). The highest heritabilities were found for the traits related to the carcass conformation, with a value of 0.45 and 0.47 respectively for CF and DP, close to what was observed in other local dual-purpose or beef cattle (Albera et al, 2001;Sbarra et al, 2013;Mancin et al, 2021c). These traits also appeared highly genetic correlated.…”

Genotype by Environment Interaction and Selection Response for Milk Yield Traits and Conformation in a Local Cattle Breed Using a Reaction Norm Approach

“…In our study, all descriptive statistics of traits match the ones reported for Rendena in previous literature [ 30 , 58 ] and were similar to other local dual-purpose breeds such as the Alpine Grey cattle [ 69 ]. The heritability of traits was also found to be close to that reported in previous studies.…”

Genomic Prediction in Local Breeds: The Rendena Cattle as a Case Study

“…We recorded little difference from the study of [ 4 ], even if our dataset was greater by an amount of about 40%. The heritabilities of these traits were similar to the ones observed in other dual-purpose (i.e., Alpine Grey; [ 36 ] or beef specialized breeds [ 37 , 38 , 39 ]). All traits appeared highly genetically correlated, especially EUROP and DP, as expected and widely reported in the literature [ 38 , 40 , 41 ].…”