Genetic analysis of udder conformation traits derived from automatic milking system recording in dairy cows

Abstract

Cartesian teat coordinates measured by automatic milking systems (AMS) provide new opportunities to record udder conformation traits and to study changes in udder conformation genetically and phenotypically within and between parities. The objective of this study was to estimate heritabilities and repeatabilities of AMS-based udder conformation traits within parities, to estimate genetic correlations between parities for AMS-based udder conformation traits, and to estimate genetic correlations between AMS-based udder conformation traits and classifier-based udder conformation traits, longevity, and udder health. Data from 70 herds, including 12,663 first-parity cows, 10,206 second-parity cows, and 7,627 third-parity cows, were analyzed using univariate and bivariate mixed animal models. Heritabilities of the AMS udder conformation traits were large (0.37-0.67) and genetic correlations between the AMS udder conformation traits and classifier-based traits were strong (>0.91). Repeatabilities within parities were large as well (0.89-0.97), indicating that a single record on udder conformation per lactation reflects udder conformation well. Genetic correlations of AMS udder conformation traits between parities were strong (0.88-1.00) and were stronger than the permanent environmental correlations. This shows that udder conformation changes over parities, but this change is mostly due to nongenetic factors. Based on these results, the current herd classification system, where cows are scored on udder conformation once in first parity, is sufficient. The AMS udder conformation traits as defined in this study have limited value as replacement for classifier-based udder conformation traits because they have smaller genetic correlations with functional traits than classifier-based traits. In summary, udder conformation hardly changes genetically between parities and is highly repeatable within parities. Udder conformation traits based on AMS need fine-tuning before they can replace classifier-based traits, and AMS teat coordinates probably contain additional information about udder health that is yet to be explored.

Genetic analyses of novel temperament and milkability traits in Norwegian Red cattle based on data from automatic milking systems

“…Genetic correlation to udder conformation would therefore call for further studies. Important udder conformation traits may also be based on teat coordinate data from AMS (Byskov et al, 2012;Carlström et al, 2016;Poppe et al, 2019). Heritabilities of pKO, pIM, and pTNF (0.12-0.14) are sufficient to obtain genetic progress if properly weighted in a selection scheme, and the genetic correlation shows that pIM and pTNF must be regarded as identical traits.…”

The future of phenomics in dairy cattle breeding

“…This includes a more frequent sampling of milk components (fat, protein, lactose, milk urea nitrogen, and somatic cell counts) and activity monitoring to identify changes in cow behavior associated with the onset of estrus, lameness, or disease and integration of real-time farm-level information (e.g., feed composition and weather). Alternative information about health comes from data recorded by automatic milking systems and electronic milking systems, such as milk yield per milking (Poppe et al, 2020), udder and teat characteristics (Poppe et al, 2019), or other electronic devices, such as sensors or cameras (Song et al, 2019). A recent, multi-institutional effort to develop a "Virtual Dairy Farm Brain" has been organized by Liang et al (2018) in order to combine expertise from scientists, dairy producers, and industry professionals for the purpose of improving whole-farm decision-making.…”

Robotic milking of dairy cows: a review

“…Jacobs and Siegford (2012a) argued that automatic sensors can memorize highly rich data sets regarding mammary health, daily and milking production, rumination time, and feed consumption in the AMS. Poppe, Mulder, Ducro and De Jong (2019) pointed out that cartesian teat coordinates measured by AMS provide new opportunities to record udder conformation characteristics, allowing studies on genetic and phenotypic changes within and between parities. For Hansen (2015), more data on herds can stimulate interest by ranchers in dairy production, but in many cases, they find themselves drowned in data.…”