Estimation of milk consumption curve parameters for different genetic groups of bovine calves

Abstract

Milk consumption was estimated for crossbred suckled calves from birth to weaning during 2 years. Breed groups utilized were Aberdeen Angus (A) and Charolais (C) sires on Fl Angus-Hereford (and their reciprocals) dams in the 1st year and in the 2nd year, sires A and Nelore (Bos indicus) (N) were used on the same type of dam. The weigh-suckle-weigh technique was employed twice a day to estimate milk consumption on a weekly basis. Estimations were adjusted by least-squares for the effects of genetic group, week of estimation, and their interaction, with sex of calf and calf and cow weights in the week of estimation as covariables. Then a non-lineal regression equation of the form: y = b0Wb1e -b2b2W was fitted for each individual, where y = milk consumption and W = week of estimation. Curves for A and C were very close in their shape, but with a greater consumption (P < 0·01) for C. For the 2nd year, there were differences among A and N both in the shape of the curve and in consumption at the peak of lactation (P < 0·01). Differences in time to peak lactation were also found: for A calves, it was week 9, for C calves week 10 and for N calves week 3·8. The N group showed a sharper decline in persistency than the other groups, suggesting different patterns in milk consumption.

Genetic relationships among direct and maternal components of milk yield and maternal weaning gain in a multibreed beef herd.

“…The estimate of 5.5% observed in this study was within the range of 2.76 to 14.5% reported for beef cattle by Marshall et al (1976), Gregory et al (1992), and Kress et al (1992). Johnston et al (1995) reported an average 32% heterosis for Cow MY (Butson and Berg, 1984;Mezzadra et al, 1989;McCarter et al, 1991). With heterozygosity of the calf affecting calf growth, an effect of heterosis of the calf on Calf MY would be expected.…”

“…Similarly, milk yield of the cow can be considered as a trait influenced by the calf and the cow. The calf can influence milk yield of the cow through demand for milk and nursing frequency (Drewry et al, 1959;Mezzadra et al, 1989).…”

Genetic parameters for milk production of Australian beef cows and weaning weight of their calves

“…In other words, Wokalup dams potentially produced more milk than the calves could drink in the suckling period allowed. Mezzadra et al (1989) reported differences in lactation curves of crossbred cows suckling Bos indicusand Bos taurus-sired calves, the former peaking earlier during lactation and showing less persistency.…”

Milk production of crossbred daughters of high- and low-milk EPD Angus and Hereford bulls.

“…1971 b). Mezzadra et al (1989) reported than Charolals calves caused their crossbred dams to produce more milk than Angus calves. found that Angus cows produced 20% (P < .05) more milk when their calves were crossbred.…”