Genetic parameters for feed intake and efficiency in lactating beef cows

Abstract

parameters of feed intike and efficiency and production traits for lactating beef cows were estimated from data collected from For personal use only.

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

“…Meyer (1994) estimated the heritability of MY in Herefords to be .12. The estimate of .35 obtained in this study was comparable to the .44, .28, and .26 found in studies by Dillard et al (1978), Diaz et al (1992), and Fan et al (1996), respectively. Heritability for milk yield was also in agreement with that observed in dairy cattle, for which estimates of .44 have recently been reported (Boettcher and Gibson, 1997) and a value of .33 is used for genetic evaluations in Canada as cited by Boettcher and Gibson (1997).…”

“…Permanent environment variance for milk yield from repeated records on cows (Cow PE ) represented 9% of phenotypic variance. This estimate of permanent environment variance as a proportion of phenotypic is similar to the .11 obtained by Meyer et al (1994) in Herefords and lower than the .17 obtained by Fan et al (1996) analyzing a subset of these data without fitting the additive genetic effect of the calf.…”

Genetic parameters for feed intake and efficiency in dry pregnant beef cows

“…Breed differences and factors related to efficiency to feed utilization for first-calf production to weaning were reported by Dinkel (1988), Freking andMarshall (1989) and Marshall et al (1990) (1984), averaging Fan et al (1996). In the first step, for estimating NE\, NE\ and NER' of cows per day, CBWPW was estimated as wbight at preiious weaning minus conceptus weight at previous weaning; CBWC was estimated as weight immediately after calving minus weight gains of uterus and udder during the dry period.…”

The genetic basis and improvement of feed efficiency in lactating Holstein dairy cattle

“…Thus selection on RFI could have a genetic impact on component traits. For milk production, this concern seems to be minimal as estimates of genetic correlations between RFI and various measures of milk production range from -0.21 to 0.12 (Van Arendonk et al, 1991;Veerkamp et al, 1995;Fan et al, 1996).…”

“…However, genetic correlations between body weight and RFI tend to be negative, ranging from -0.32 to 0.01 (van Arendonk et al, 1991;Veerkamp et al, 1995;Fan et al, 1996). On the other hand, genetic correlations between RFI and change in BW tend to be more positive, ranging from -0.03 to 0.57 (van Arendonk et al, 1991;Veerkamp et al, 1995).…”