The Reproductive and Productive Performance of Holstein-Friesian Cattle under Libyan Conditions

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Date
2015-06-23
Authors
El Siddig,Ayat Omer Elkhalil,
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Publisher
University of Khartoum
Abstract
This study was conducted to investigate the reproductive and productive performance, and to estimate some genetic parameters of these traits in Holstein-Friesian cattle at Goat EI-Sultan station in Libya. Data of the first three lactations covering the period from 1983 to 1993 were studied. The results revealed that the sire had a highly significant (P<0.01) effect on age at first calving and open period. The effect of sire on milk yield, corrected milk yield and daily milk yield was highly significant (P<0.00I), and there was a significant (P<0.01) effect of sire on lactation length. The calving year-season had a highly significant effect (P<0.001) on age at first calving and open period. It affected significantly (P<0.001) milk yield, corrected milk yield, daily milk yield and lactation length. Parity had a significant (P<0.05) effect on open period, and lactation length. It also had a highly significant (P<0.001) effect on milk yield, corrected milk yield and daily milk yield. Linear and quadratic regressions on milk yield had a significant (P<0.001) and P<0.05, respectively) effect on calving interval and open period. Linear regression on age at first calving significantly (P<0.0) affected milk yield, corrected milk yield and daily milk yield. Linear regression on lactation length had a highly significant (P<0.001) effect on milk yield, corrected milk yield and daily milk yield. The results showed that the heritability of the reproductive traits studied were 0.41±0.08, 0.02±0.02 and 0.46±:0.08 for age at first calving, calving interval and open period, respectively. Heritability of the productive traits studied were 0.07±0.3, 0.07±0.03, 0.06±0.03 and 0.04±0.02 for milk yield, corrected milk yield, daily milk yield and lactation length, respectively.
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Keywords
Reproductive;Productive Performance;Holstein;Friesian Cattle
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