Beef production from the dairy herd: calving performance of cows

Abstract

Data are reported on the calving performance of cows in beef production trials in three successive calvings of South Auckland herds. The main comparison of Friesian, Hereford, and Charolais sires over the Jersey cow is supplemented by information on the Friesian cow mated to these three sire breeds and on straightbred Jersey and straightbred Angus calvings.Overall, 81% of ca1vings were unobserved. Eight percent of all ca1vings, or 45% of observed calvings, were assisted. Jersey and Friesian cows required more assistance when calves were sired by Charolais and Friesian sires, and least when Hereford sires were used.Cow mortalities at calving time were greatest for Jersey and Friesian cows in-calf to Charolais sires. Perinatal calf mortalities accounted for 3.5% of all calves born, with a greater mortality of calves by Charolais sires than other breeds.Calves assisted at birth were heavier than those from unassisted calvings, but gestation lengths did not differ significantly. Calves dying at birth had a shorter gestation period and were lighter than surviving calves.There were significant sire and farm effects on birth weight and gestation length of Jersey crossbred calves, and age of dam significantly affected birth weight but not gestation length. Bull calves had longer gestation periods and were heavier at birth than heifers. Sire breed affected calf birth weights in the descending ranking order of Charolais, Friesian, Hereford, and Jersey. Purebred Angus calves were similar in birth weight to Hereford X Jersey crossbreds. Friesian cows produced heavier calves than Jersey cows. Gestation periods were longest for calves with Charolais sires; those sired by the Hereford were next longest; and Friesian and Jersey sire breeds had the shortest gestations.Heritabilities of birth weight and gestation length were calculated as 0.31 and 0.12 respectively.Results are discussed in relation to beef breeding programmes.

Beef production from the dairy herd

“…An acceptably accurate assessment of the dystocia incidence associated with individual bulls, such as that provided for some bulls in the New Zealand Dairy Board's artificial breeding service, would be of distinct value to the dairy farmer faced with the choice of alternative bulls of the fame breed. Statistically significant variation between sires-within-breeds for birth weight and gestation length was also found previously (Everitt & Jury 1972), and the present heritability estimates are comparable for birth weight, but higher for gestation length, than reported by those autho,'s. Heritability of calving difficulty, subjectively assessed, appears low (Brinks et ai, 1973: Hansen 1975Tong et ai.…”

“…This suggests that some farmers may have anticipated difficult calving for cows in-calf to some sire breeds and rendered assistance whether it was needed or not. There was no evidence of farmers anticipating calving difficulties in a previous study (Everitt & Jury 1972) which reported calving of F and J cows in-calf to C sires over three successive calving seasons.…”

“…To obtain sufficient cows for insemination each year the approach used was that adopted in previously reported studies on beef production from [he dairy herd (Everitt 1967Everitt et al 1969;Everitt & Evans 1970;Everitt & Jury 1972). South Auckland dairy farmers participated by offering a minimum of 45 Friesian cows for the experimental matings.…”

“…Thus age and parity of cow and sex of calf are specific, but birth weight of the calf is also important and is influenced by these, as well as by genotype and gestation length. Everitt & Jury (1972) found that environmental effects were an important source of variation for some characteristics at calving. The effects of 12 factors on gest:::tion periods in New Zealand dairy cattle have been reported by Macmillan & Curnow (1976) .…”

“…Calving difficulty (dystocia) has been found to increase calf mortality , adversely affect subsequent fertility , reduce lifetime productivity (Brinks et al 1973;Phillipson 1976a, e), and impose additional management stress. Everitt & Jury (1972) emphasised the importance of the latter feature in New Zealand through the increased labour input at calving time in large dairy and beef herds, managed under grassland conditions without housing and with marked seasonality of calving.…”