Vi. Cardoso et al., GENETIC ASSOCIATION BETWEEN MILK-PRODUCTION AND WEIGHT PERFORMANCE OFPITANGUEIRAS CATTLE (5 8-RED-POLL-3/8-ZEBU)/, Brazilian journal of genetics, 18(4), 1995, pp. 533-540
Data on 1,567 first lactations and 1,776 records of steers, including
body weight at time of allocation to feedlot and live-weight-for-age,
of Pitangueiras cattle were used to estimate predicted differences of
sires. Data were also used to compute the genetic correlation between
milk and weight traits, and to calculate expected correlated responses
for weight performance traits. Animals were raised in Sao Paulo State
and males were allocated to the feedlot at an average age of 28 month
s. Overall means and coefficients of variation (CV) were respectively
1,930 kg (CV = 56%), for 305-day milk yield (MY305); 234 days (CV = 50
%), for lactation length (LL); 28 months (CV = 17%) and 365 kg (CV = 1
6%), for age and body weight at allocation to the feedlots (AGEI and W
AF); and 0.421 kg (CV = 13%), for live-weight-for-age (LWA). Predicted
differences for MY305, WAF and LWA ranged from -521 to 612 kg; -14 kg
to 22 kg; and -0.014 kg to 0.021 kg, respectively. The genetic correl
ation between MY305 acid WAF was -0.24 +/- 0.15 and -0.35 +/- 0.14 for
MY305 and LWA. The correlated responses for WAF and LWA resulting fro
m direct selection for milk production were 1.667 kg and 0.0016 kg, re
spectively. Selection for milk production did not cause detrimental ef
fects on weight of animals raised for beef.