Prospects of reducing calf losses by means of breeding
W. JUNGE, E. STAMER, N. REINSCH and E. KALM
The rates of dystocia and stillbirth in Holsteins are increasing over time especially in first calving heifers. The current study aimed to test the relevance of birthweight of calves as an information trait in breeding value estimation for calving ease and stillbirth rate. The data of 12968 calves born on three commercial farms were analysed. The paternal heritibilities of calving traits (calving ease, stillbirth rate) were low, high values were obtained for birth weight. The genetic correlations between calving ease, stillbirth rate and birth weight were favourable and for that reason birth weight was integrated in the estimation breeding values. The reliabilities of breeding values increased by 7 to 33 percent for calving ease and 7 to 19 percent for stillbirth rate when birthweight is included in the evaluation depending on the number of offsprings per sire. Opposite to other studies the rank correlations between paternal and maternal breeding values are positive in the present investigation. Data of birth weight of Holstein calves are useful for selection purposes to reduce calf losses.