Crossbreeding of imported and native goats in a dry tropical environment. II. Production and reproduction
Mixed model techniques were used to analyze reproductive and productive traits of Native and Crossbred goats from 1969 to 1978 in an experiment at Loma de Leon Field Station in Venezuela. Breed groups used were: Native, ¢ Nubian ¢ Native, ¢ Alpine ¢ Native, ¢ Toggenburg ¢ Native, 3/4 Nubian + Native. Percentage of singles, twins, triplets, abortions, and stillborn for above breed groups were: 47.3, 43.3, 3.2, 4.7, 1.5; 33.5, 46.6, 5.3, 9.5, 5.1; 36.1, 50.0, 4.1, 4.9, 4.9; 50.0, 40.2, 2.0, 5.9, 2.0; 42.5, 36.3, 5.6, 8.1, 7.5; and 42.2, 43.8, 4.0, 6.5, 3.4, respectively. Multiple births increased with parity. Least squares means for reproductive traits of the groups were kidding interval days: 304.7, 355.8, 356.8, 360.3, 403.1; days to first postpartum estrus: 145.8, 175.0, 172.4, 171.1, 222.8; postkidding dam weight kg: 39.3, 42.1, 45.9, 38.6, 42.0, respectively. Repeatabilities of above traits were: 0.033, 0.018 and 0.51. Kidding interval increased significantly as the proportion of introduced genes increased. No significant differences were found between breed groups for litter size, days gestation length, services per conception, or days age at first kidding. Means for these traits were: 1.7, 149.4, 1.16 and 685.1. Kidding interval and first postpartum estrus were positively related to length of previous lactation, and were negatively related to weight at previous parturition. Group least squares means for kg milk yield were: 57.2, 97.7, 150.5, 115.3, 95.6, and for days lactation length: 151.0, 182.4, 195.0, 191.8, and 183.8, respectively. Milk yield and lactation length were both positively related to postkidding weight of dam
| Main Authors: | , , , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Published: |
Scottsdale, AZ (EUA)
1982
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