Genetic and environmental factors affecting the incidence of difficult calving and perinatal calf mortality in Israeli-Friesian dairy herds

Abstract

SUMMARYRecords of 178 593 monoparous births between 1964 and 1970 in Israeli-Friesian dairy cattle were analysed for information on environmental and genetic factors affecting calving difficulties and perinatal mortality. The incidence of difficult calvings (DC) and peri-natal calf mortality (PM) were 6·9 and 9·1% in heifer calvings, and 1·6 and 4·1% in cow calvings. Calving characters were not related t o heifer age nor cow parity, but there was a seasonal trend in heifer calvings, with both DC and PM being high in winter and low in summer calvings.Heritability estimates for calf-genotype effects on PM were 0·042 in heifer calvings and 0·013 in cow calvings. Heritability estimates for dam-genotype effects on PM were 0·018 and 0·004 respectively. Heritability estimates for DC were similar t o those for PM. The genetic correlations between DC and PM in the same class of calvings ranged between 0·8 and 0·9, while the environmental correlations were considerably lower, about 0·3. The genetic correlations between the calf-genotype effects in heifer and cow calvings were about 0·5, indicating that different factors may affect heifer and cow calvings.It is proposed that sires already proven for milk yield be tested for their calf effects in heifer calvings, using contemporary comparisons within herds and seasons. Results will be available when the sires are 6 to 6½ yr old. Sires causing fewest calving difficulties would be nominated for heifer matings, so that most heifer inseminations would be by sires proven for both yield and calving characters. Some long-term progress might be obtained if sires with a high incidence of difficulties in their heifer mates were not used to produce young sires.

Dystocia in dairy cattle. Age of dam, maternal considerations, and relationships with economic traits

“…The authors postulated that increased exercise while on pasture and reduced observation by herdsmen which resulted in some semi-difficult births being recorded as easy were two possible reasons for summer births being less difficult. Similar seasonal effects (more difficulty in winter births) were reported by Bar-Anan et al (1976) in Israeli heifer (first parity) but not cow (second and greater parity) calvings and by Philipsson (1976b) in Swedish Friesian heifers. Philipsson (1976b) also reported seasonal variation in calving performance was unrelated to variation in birth weight and gestation length and concluded less difficulty in summer calvings could be attributed to increased exercise and daylight.…”

“…Bar-Anan et al (1976) and Philipsson (1976b) reported two to three times more dystocia in first parity dams. Philipsson (1976b) reported frequencies of difficult calving to be 15.7% in heifers versus 4.8% in cows.…”

“…Extensive research on dystocia has been conducted in Sweden by Philipsson (1976aPhilipsson ( , 1976bPhilipsson ( , 1976cPhilipsson ( , 1976dPhilipsson ( , 1976e, 1977, Israel by Bar-Anan et al (1976), and France by Foulley and Menissier (1979).…”

“…Teixeira (1978) reported constant estimates of .78, .04 and .00 for parities one through three, respectively. Philipsson (1976bPhilipsson ( , 1976c and Bar-Anan et al (1976) analyzed first and later parity records separately. The logical break for parity of dam partitioning, thus, seems to be first versus later parity.…”

“…Genetic correlations can also be estimated by computing the additive genetic covariance using sire transmitting abilities (Wiggans et al, 1980) or using a multiple trait model (Schaeffer and Wilton, 1978). Bar-Anan et al (1976) reported the only genetic correlation (.5) in the literature from a large body of data. This result casts doubt on the use of cow data to improve estimation of sire merit when used on heifers.…”