By Boelling, D. and Pollott, G. E., Livestock Production Science, 1998
Description
Genetic parameters were estimated for locomotion and the Linear type traits rump angle (RA), udder depth (UD), rear leg side view (RLSV), foot angle (FA) and the index value, total score (TS) in dairy cows. The analyses were based on four data sets containing records of 30,845, 10,845, 4379, and 1601 cows in their first to fourth lactation, respectively, collected from all Holstein-Friesian cows classified in Great Britain and Ireland during 1994. A sire model was used to analyse the data. In the analysis of data of first lactation cows, sires were treated as either random or regarded as fixed or random, depending on their age. Locomotion showed a heritability of about 0.10 for all age groups. The genetic correlations between locomotion and RA or UD showed no clear trend for the different lactation groups. For RLSV, it increased from 0.33 to 0.78 and for FA, from -0.58 to -0.96. Locomotion analysed as the binary trait, lame or non-lame, was virtually non-heritable (h(2) 0.01), but exhibited similar correlations to FA and RLSV as locomotion. Breeding values were simultaneously estimated for locomotion, RLSV and FA. EBVs for locomotion clustered around the mean with minimal spread and were moderately correlated with those for FA and RLSV. The development of breeding values over time, assessed by comparing the mean values for different sire age classes, showed a clear trend in the desired direction for FA and RLSV. No such trend was found for locomotion. (C) 1998 Elsevier Science B.V. All rights reserved
Genetic parameters were estimated for locomotion and the Linear type traits rump angle (RA), udder depth (UD), rear leg side view (RLSV), foot angle (FA) and the index value, total score (TS) in dairy cows. The analyses were based on four data sets containing records of 30,845, 10,845, 4379, and 1601 cows in their first to fourth lactation, respectively, collected from all Holstein-Friesian cows classified in Great Britain and Ireland during 1994. A sire model was used to analyse the data. In the analysis of data of first lactation cows, sires were treated as either random or regarded as fixed or random, depending on their age. Locomotion showed a heritability of about 0.10 for all age groups. The genetic correlations between locomotion and RA or UD showed no clear trend for the different lactation groups. For RLSV, it increased from 0.33 to 0.78 and for FA, from -0.58 to -0.96. Locomotion analysed as the binary trait, lame or non-lame, was virtually non-heritable (h(2) 0.01), but exhibited similar correlations to FA and RLSV as locomotion. Breeding values were simultaneously estimated for locomotion, RLSV and FA. EBVs for locomotion clustered around the mean with minimal spread and were moderately correlated with those for FA and RLSV. The development of breeding values over time, assessed by comparing the mean values for different sire age classes, showed a clear trend in the desired direction for FA and RLSV. No such trend was found for locomotion. (C) 1998 Elsevier Science B.V. All rights reserved
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