ABSTRACT
EFFECTS OF COW SIZE AND MILK YIELD ON BEEF COW
PRODUCTION EFFICIENCY
Gertrude S. Aboagye, M.Sc. Supervisor;
University of Guelph, 1976 Dr. J.W. Wilton
Data on 5 groups of cow and Angus-sired first-calf pairs representing
year and season of calving subclasses were analysed within
groups for effects of cow size and milk yield on 180-day weaning weight
and efficiency of production. There were 15, 20, 22, 32 and 38 covrcalf
pairs in groups 1 to 5 respectively. There were 3 criteria for
size: height at withers, post-calving weight and length of cow. The
milk criteria were 180-day milk yield and 180-day milk fat yield.
Efficiency was estimated as the ratio of calf weaning weight to total
TDN consumption of cow and calf during lactation. Interactions between
the effects of milk and size were examined and the data were analysed
for relationships between the various criteria for cow size and milk
yield.
Milk yield was generally positively associated with the various
measures of cow size. With regard to 180-day weaning weight, interactions
between height at withers and total milk yield were significant
in 2 of 4 groups. When efficiency was considered, interaction was significant
in 1 of 4 groups. The effect of sex was generally non-significant.
Regression coefficients of 180-day weaning v/eight on height
at withers where cows were classified into low, medium and high classes
within group ranged from -4.7 to 5.7 Kg/cm. The regression coefficients
were generally positive and significant indicating an increase in
weaning weight associated with increased height at withers. When
efficiency estimates were regressed on height at withers, the
regression coefficients were very low and generally negative.
Regression of 180-day weaning weight and efficiency on total milk
yield for the different height classes showed that both 180-day
weaning weight and efficiency increased with the amount of milk
produced by the dam.
There was no interaction effect between total milk yield and
post-calving weight of cow on 180-day weaning weight and efficiency
in any of the 5 groups. Regressions of 180-day v/eaning weight on
weight of cow were positive and significant in 4 of 5 groups indicating
an increase in weaning weight associated vtith increased weight
at calving. Regressions ranged from -0.1 to 0.4 Kg calf weight/Kg
cow weight. None of the regressions of efficiency on post-calving
weight was significant.
Interaction between total milk yield and length of cow was
significant in 1 of 5 groups. When fat yield was considered, there
was no interaction effect between yield of fat and the 3 size criteria
in any of the 5 groups, but fat yield had a significant effect on both
180-day weaning weight and efficiency in 3 of 5 groups.
ABOAGYE, G (2021). EFFECTS OF COW SIZE AND MILK YIELD ON BEEF COW PRODUCTION EFFICIENCY. Afribary. Retrieved from https://tracking.afribary.com/works/effects-of-cow-size-and-milk-yield-on-beef-cow-production-efficiency
ABOAGYE, GERTRUDE "EFFECTS OF COW SIZE AND MILK YIELD ON BEEF COW PRODUCTION EFFICIENCY" Afribary. Afribary, 31 Mar. 2021, https://tracking.afribary.com/works/effects-of-cow-size-and-milk-yield-on-beef-cow-production-efficiency. Accessed 13 Nov. 2024.
ABOAGYE, GERTRUDE . "EFFECTS OF COW SIZE AND MILK YIELD ON BEEF COW PRODUCTION EFFICIENCY". Afribary, Afribary, 31 Mar. 2021. Web. 13 Nov. 2024. < https://tracking.afribary.com/works/effects-of-cow-size-and-milk-yield-on-beef-cow-production-efficiency >.
ABOAGYE, GERTRUDE . "EFFECTS OF COW SIZE AND MILK YIELD ON BEEF COW PRODUCTION EFFICIENCY" Afribary (2021). Accessed November 13, 2024. https://tracking.afribary.com/works/effects-of-cow-size-and-milk-yield-on-beef-cow-production-efficiency