Genetic and environmental factors influencing growth rate and body weights up to six months in Malabari goat
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Date
2003
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Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy
Abstract
Goats contribute a major share of the meat produced in India so it is
worthwhile to evolve and propagate meat type goats suited for the humid tropics of
India particularly to Kerala state. Malabari goat has got high adaptability, crude
fibre conversion efficiency and prolificacy. So breeding programs can be
developed on that breed to evolve meat type. The effects of sex, type of birth,
month of birth, sire and dam's body weight at kidding on birth, weight, weaning
weight, weight at 180 days and body weights at fortnightly interval in 113
Malabari kids were assessed. Heritability estimates were made for body weight at
different ages. Correlations were worked out on body weights, milk yield and
dam's body weight at kidding. This research approach was aimed at ascertaining
the feasibility of evolving a selection criteria for the development of a meat type
goat.
Overall means for birth weight, weaning weight and weight at 180 days
were 1.79 ± 0.046, 6.48 ± 0.211 and 11.04 ± 0.322 kg respectively. Sex had a
significant effect on birth weight, weaning weight, weight at 180 days, pre-
weaning and post-weaning body weights. Means of birth weight, weaning weight
and weight at 180 days for male kids were 1.87 ± 0.059,6.77 ± 0.267 and 11.79 ±
0.407 kg and that of females were 1.73 ± 0.046,6.19 ± 0.252 and 10.29 ± 0.384 kg
respectively. Males were found to be heavier than females at all stages of growth.
Birth type of kids had significant effect on birth weight and pre-weaning
body weights and no significant effect was found on weaning weight, post-
weaning body weights and weight at 180 days. Means body weights for single,
twins, triplets were 2.03 ± 0.070, 1.83 ± 0.049 and 1.54 ± 0.096 kg at birth, 6.96 ±
0.319, 6.46 ± 0.226 and 6.01 ± 0.435 kg at weaning and 11.27 ± 0.487 kg, 10.80 ±
0.344 kg and 11.06 ± 0.664 kg at 180 days of age. Single born kids were found to
be the heaviest followed by twins and triplets at birth and weaning. At 180 days of
age singles were found to have higher weight, followed by triplets and twins.
Singles had higher weights in pre-weaning growth followed by twins and triplets
where as twins and triplets showed a compensatory growth in the post-weaning
period.
Month of birth had a significant effect on pre-weaning weights where as the
effect was not significant on birth weight, weaning weight, post-weaning weight
and weight at 180 days. Kids born in May, June, July and August had higher
weights in pre-weaning growth than those born in September, October, November
and January.
Sire effect was found to be non significant on body weights at all ages.
Heritability estimates of birth weight, weaning weight and weight at 180 days were
0.30 ± 0167, 0.35 ± 01n and 0.35 ± 0.276 respectively. Dam's body weight at
kidding was found significant on body weights from 168 days only.
Birth weight had significant correlation (0.534) with weaning weight. A
significant correlation (O.2()5) was found between weight u\ Wl'llnillg uud IHO d:lY~.
Correlations between Birth weight and weight at 180 days was not significant. A
significant correlation also noticed between milk yield and the pre-weaning body
weights of kids. Correlation of dam's body weight with milk yield (0.379), litter size
(0.477) and litter weight (0.558) was found to be significant.
Singles had higher body weight from birth to weaning followed by twins and
triplets. But it was observed that there was no significant difference among kids of
different type of birth in the post-weaning period. The triplets had a compensatory
growth during the post-weaning period. Dam's weight at kidding influenced body
weight of kids from 168 days. The present study reveals body weight of the mother is
the major factor, which decides the type of birth. Higher the weight at kidding larger
will be the litter size and level of production of milk.
So based on the above result it is suggested that the selection to evolve the
meat type of breed should be directed towards type of birth. Body weight of dam is a
prime trait to be considered in selection by which the litter size, milk production of
dam and body weight of kids at the age of slaughter could be improved.
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