Abstract
A useful criterion for evaluating the productivity of a cow is the total weight her calves attain. This measure of productivity is a function of weight, lifetime fertility and the gain potential of the calves. Weights studied were birth weight, 180-day weaning weight and yearling weight of calf and weight of dam usually taken within 10 days after parturition. The data were collected at the Texas A&M Agricultural Research Center at McGregor from 1950 to 1970. All weights were transformed to natural logarithms before analyses. Homogeneity of regressions of progeny birth and weaning weight on weight of the dam was tested across age of dam, sex of calf classes on 901 pairs of Hereford calves and their dams. No significant heterogeneity of regressions was found among age of dam or sex subclasses. Homogeneity of regressions of progeny birth, weaning and yearling weight on weight of the dam was tested for breed of dam groups. Dams were grouped into 15 breed of dam groups for birth and weaning weight analyses and in to 14 for yearling weight analyses. The number of dam and progeny pairs were 2804 for birth and weaning weight and 2166 for yearling weight. Regressions of progeny weight on weight of the dam were not significantly heterogeneous for progeny birth or yearling weight. They were heterogeneous for progeny weaning weight; but the heterogeneity was of small magnitude. ...
Miquel, Maria Cristina (1972). Influence of dam weight on her productivity. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -185442.