On the relation between milk production and fertility in Kibbutz dairy cattle herds

Abstract

SUMMARYMilk production (305 day lactations, 3·5% fat-corrected milk), and lengths of time between calving and conception for 541 heifers and 1127 older cows were examined. These data were collected from 11 herds in collective farms in Israel during two successive years. Herd lactation means ranged from 5046 to 8570 kg for cows and from 5021 to 7250 for heifers; the ranges of time between calving and conception were 89–123 days and 99–141 days, respectively.A significant correlation was found between the weight of milk given per lactation and the length of the interval between calving and the next conception, with coefficients of 0·298 (cows) and 0·333 (heifers). There was a positive non-linear regression of length of calving to conception interval on production of milk, the regression line becoming steeper, both for cows and heifers, as yield rose.All herds practised first insemination at the first heat exhibited after 60 days from calving. The results indicate that, when this is done, cows yielding 8000 kg or over per lactation, and heifers yielding 6750 kg or over, will show calving to conception intervals exceeding a mean length of 110 days.

Reproductive Performance from Daughters of Single and Multiple Trait Selected Sires

“…The higher producing Yield cows had a 14 day shorter calving interval than Merit cows. These results differ from those of others (4,7,21,25) who found that higher producing cows had more days open and longer calving intervals than lower producing cows.…”

Factors influencing the fertility of a cattle population

“…Opinions on the effect of the milk yield on fertility are also divided. Some workers were able to show that the milk yield had a marked effect (Hewett, 1968 ;Francos & Rattern, 1975;Spalding, Everett & Foote, 1975), others failed to do so (Metz&Politiek, 1970;Koopman & Wijbenga, 1973. A diagnosis of cystic ovarian disease is more common in cows with high milk yield than it is in those showing lower milk yields (Roberts, 1971b;Whitmore et al, 1974b).…”

Genetic relationship of yield and fertility in dairy cattle

“…Matsoukas and Fairchild (1975) regressed several measures of fertility on 305-day FCM that was adjusted for age and days open and detected some indication of slight antagonism between yield and fertility. Francos and Rattner (1975) Daily milk yield, days to first breeding, number of services, and calving interval were evaluated by Holtz et al (1976) for 61,109…”