Factors affecting weigh-suckle-weigh milk yield estimates and calf performance of zebu cattle
Abstract
One hundred and twentv (120) Sahiwal cows suckling either
Sahiwal calves or Friesian x Sahiwal calves and 180 Boran cows
suckling Boran calves or Friesian x Baran calves were used in the
suckling study. Milk yield and calf weight data were obtained by
Weigh-Suclde-Weigh (WSW) method once per week for 36 weeks from
1969 through 1972. Both milk yield/intake and calf performance
(average daily gain and weaning weight) were analvsed by a Least
Squares Computer Programme (Rege, 1986) for the effect of calf
breed, calf sex, season and year of birth on milk vield/intake
and growth traits of the calves. The effect of milk production
of the dam and of rearing method on growth performance of the
calves' were also analysed by the same method. For comparison 130
handfed Sahiwal calves reared in the same vear and 300 handmilked
Sahiwal cows were used in growth performance and milk yield
estimates, respectively.
Total milk yield estimates (1272.35 kg) and calf growth rate
per day and weaning weight (0.66 kg and 187 kg respectively) as
determined bv the WSW method showed that Sahiwal and Boran cows
were quite similar in their milk production therefore were
grouped together. Their Friesian cross calves also Berformed
similarly in growth rate but Friesian x Sahiwal (FS) calves were
slightly superior to Friesian x Boran (FB) calves in weaning
weight. Both groups of crossbred calves were 18% heavier than
their respective straightbred counterparts in average daLly ga.in.
Coefficient of
yield determination
handmilking (23.75%
variation obtained by WSW method for milk
was quite similar to that obtained for
and 21.84% respectively) indicating
comparable accuracy in determining milk yield by the two methods.
Correlation between monthly mi lk yield and monthly we ight; gains
were highest in the second to fifth months (r=O.53) indicating
that monthly tests in the first 5 months would be adequate to
assess milk production of the cows and growth performance of
suckling calves. Peak milk production by WSW coincided with peak
rate of weight gain (in the second month) supporting the use of
WSW method for determination of both traits.
The effect of calf breed, calf sex, season, year, initial
weight of calf, weaning age and milk yield of the dam were highly
'significant for growth traits of the calf while age of dam was
not significant. Milk yield of dam was also significantly
influenced by calf breed, season, year and initial weight of the
calf but not by age of dam and sex of calf.
Citation
Master of Science in Animal SciencePublisher
University of Nairobi Department of animal production