GENETIC STUDIES ON PRODUCTION AND REPRODUCTION TRAITS OF ONGOLE CATTLE
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Date
2006-02
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA
Abstract
ABSTRACT :
The data on Ongole cattle at Cattle Project, Livestock Research Station, Lam farm, Guntur and Cattle Breeding Farm, Chadalawada, Prakasam district from 1987 to 2005 were analyzed for studying the mean performance and estimation of genetic parameters of various production and reproduction traits. The overall least squares means of body weights at birth, 1, 3, 6, 12, 18 and 24 months of age were 26.27, 47.77, 69.38, 102.81, 147.77, 197.43 and 251.15 kg, respectively. The body weights of Ongole cattle were significantly affected by the period of birth from 1 to 24 months of age whereas season of birth influenced the body weights at birth and one month age only. The sex of the animal influenced the body weights of the animals at all the ages studied.
The overall least squares means for height at withers, chest girth and body length of Ongole cattle from birth to 24 months of age ranged from 73.09 to 133.30 cm, 69.24 to 145.73 cm, and 59.54 to 125.58 cm, respectively. The overall least squares means for total lactation milk yield, 305-days lactation milk yield, lactation length, peak yield, days to reach peak yield, milk yield per day of lactation and milk yield per day of calving interval were 620.49 kg, 607.91 kg, 232.26 days, 3.90 kg, 49.94 days, 2.77 kg and 1.37 kg, respectively. The effect of farm was significant on all the production traits studied, except on milk yield per day of calving interval. Period of calving and order of lactation influenced all the production traits, except days to reach peak yield, while season of calving had no significant influence on any of the production traits studied. The overall least squares means of age at first calving, gestation period, service period, dry period, calving interval, number of inseminations per conception and breeding efficiency by Jain’s formula, Tomar’s formula and Wilcox’s formula were 1448.48 days, 221.24 days, 242.92 days, 294.04 days, 534.82 days, 1.78 and 87.07 %, 77.36 % and 72.07 %, respectively. The farm and period of calving significantly influenced the age at first calving, service period, dry period, calving interval and breeding efficiency by all the three formulae. Season of calving had no significant influence on any of the reproduction traits studied. Order of lactation significantly affected the gestation period, service period, dry period, calving interval and breeding efficiency estimated by all the three methods. The heritabilities of body weights ranged from 0.05 + 0.05 at birth to 0.51 + 0.24 at 12 months age in males and from 0.04 + 0.06 at 6 months age to 0.25 + 0.16 at 24 months age in females. The heritabilities of height at withers, chest girth and body length ranged from 0.02 to 0.35, 0.04 to 0.44 and 0.05 to 0.63, respectively in males and from 0.17 to 0.33, 0.07 to 0.39 and 0.15 to 0.30, respectively in females. The genetic correlations of body weight with height at withers, chest girth and body length ranged from 0.56 to 0.82, 0.33 to 0.89 and –0.06 to 0.84 in males and from 0.06 to 0.82, 0.47 to 0.96 and –0.38 to 0.60, respectively in females. The chest girth was highly correlated with body weight at various ages. The magnitude of such correlations varied from 0.15 to 0.39 in males and 0.13 to 0.39 in females. The phenotypic correlations of height at withers with chest girth and body length at various ages ranged from 0.07 to 0.27 in males and from –0.22 to 0.34 in females. The phenotypic correlations between the chest girth and body length ranged from 0.07 to 0.33 in males and 0.02 to 0.36 in females. The heritabilities of calving interval, total lactation milk yield and breeding efficiencies based on Jain’s, Tomar’s and Wilcox’s formulae were 0.49, 0.61, 0.43, 0.75 and 0.40, respectively. The genetic correlations of calving interval and total lactation milk yield with all the measures of breeding efficiency were negative. The calving interval was generally positively correlated with total lactation milk yield (0.46 + 0.05). The genetic correlations among the three formulae of breeding efficiency ranged from 0.46 to 0.84. The phenotypic correlations of calving interval and total lactation milk yield with breeding efficiency by all the three formulae ranged between –0.62 to 0.14, whereas these correlations between three formulae of breeding efficiency were all positive and ranged from 0.28 to 0.37. The estimates of heritability based on overall lactations for total lactation milk yield, 305-days lactation milk yield, lactation length, peak yield, days to reach peak yield, milk yield per day of lactation and milk yield per day of calving interval were 0.46, 0.48, 0.33, 0.45, 0.10, 0.45 and 0.46, respectively. The heritabilities for gestation period, service period, dry period and calving interval were 0.18, 0.10, 0.23 and 0.12, respectively. The genetic correlations of total lactation milk yield with other production traits ranged from 0.40 to 1.00. Its correlation with reproduction traits varied from –0.63 to 0.07 The genetic correlations of 305-days lactation milk yield ranged from 0.38 to 0.97 with other production traits and from –0.63 to 0.05 with reproduction traits. The genetic correlations of lactation length varied from 0.47 to 0.97 with other milk production traits and with the reproduction traits the estimates ranged between–0.78 and -0.11. The phenotypic correlations of total lactation milk yield with other production and reproduction traits varied from –0.26 to 0.50 and 305-days lactation milk yield with other traits ranged from –0.26 to 0.47. The lactation length was correlated positively with all the other production traits and negatively with gestation period (-0.12) and dry period (-0.28). The milk yield per day of lactation and milk yield per day of calving interval were phenotypically correlated negatively with all the reproduction traits studied. The overall phenotypic correlations of gestation period were 0.01, 0.09 and 0.02 with service period, dry period and calving interval, respectively while these estimates of service period with dry period and calving interval were 0.39 and 0.50, respectively.
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