Growth curve analysis in Mecheri sheep
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Date
2020-02
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Abstract
Livestock keeping is an important avocation for the poor in the developing world, especially in India,
contributing to rural livelihood and offering pathways to come out of poverty. Among the livestock, the sheep
is an economically important species contributing greatly to the Indian agrarian economy, playing a vital role
for the livelihood of a large number of small and marginal farmers and landless labourers. In addition to meat
and wool, manure from sheep is an important source of organic fertilizer, especially in southern states where
they are penned on fallow lands for increasing soil fertility. Mecheri sheep are one of the recognized breeds of
sheep in Tamil Nadu and reared mainly for meat with the primary by-product as skin. They constitute 24.28
per cent of total sheep population of Tamil Nadu.Data on growth traits of Mecheri lambs born between the
years 1991 and 2014 in Mecheri Sheep Research Station, Pottaneri were utilized for this study. The overall
least-squares means (± S.E.) of body weights at birth, 3, 6, 9 and 12 months of age were 2.37 (± 0.008), 9.61
(± 0.062), 12.56 (± 0.071), 15.32 (± 0.085) and 17.87 (± 0.102) kg, respectively. Lambs born during the
months of July-September had the highest (2.44±0.018 kg) birth weight and the least birth weight (2.14 ±
0.014 kg) was found among lambs born during the months January-March. Similarly, lambs born during the
periods July-September and January-March had the highest (10.06 ± 0.127 kg) and least (7.74 ± 0.099 kg)
weaning weights, respectively. Also, the highest yearling weight (18.70 ± 0.216 kg) was found in lambs born
during the months July-September and the least weight (16.48 ± 0.177) was found during the months January-
March. The overall least-squares means of Absolute Growth Rate (g/day) measures over the age intervals of
birth to 3 months, 3 to 6 months, 6 to 9 months and 9 to 12 months were 79.97 ± 0.56, 40.01 ± 0.44, 33.73
± 0.46 and 31.34 ± 0.86, respectively. Among non-linear growth models fitted to evaluate growth pattern,
the Brody function was found to be the best fitted model in describing the growth curve patterns of both ram
and ewe lambs of Mecheri sheep, which was followed by Von Bertlanffy, Gompertz, Logistic and Richards
models in the order of the goodness of fit. The predicted body weights through Brody model at birth, 3, 6, 9
and12 months of age were 2.57, 8.92, 13.03, 15.70 and 17.50 kg, respectively in Mecheri sheep. The study
showed that the Brody function adequately fitted the growth rate of Mecheri sheep, which is a medium sized
breed with moderate growth. Further, Influences of environmental factor such as months of lambing and sex
of the lambs born were well captured by the Brody model.
Description
TNV_20thMVC_PP_Feb-2020_PA58
Keywords
Veterinary Science