University of Khartoum

The Effect of Season of Calving and Some Managerial Practices on the Pattern of Persistency of Exotic Dairy Cows in the Sudan

The Effect of Season of Calving and Some Managerial Practices on the Pattern of Persistency of Exotic Dairy Cows in the Sudan

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Title: The Effect of Season of Calving and Some Managerial Practices on the Pattern of Persistency of Exotic Dairy Cows in the Sudan
Author: Khalda Abd El Wahid Mohamed, Ali
Abstract: This study was initiated to look into the effect of season of calving, parity number and calving interval on lactation persistency of imported Holstein-Friesian cows in two farms: Butana and Dairy Land Farms. Correlations with average yield for 180 days and average lactation yield were also estimated. Two models for calculation of persistency: Pm and P3:3 were adopted. It was observed that the overall lactation persistency was 1:19 ±0.23 and 73.00±15.72 for Pm and P3:3 models, respectively in Butana Farm 1:49±0.44 and 69.17±18.49 for Pm and P3:3 models for Dairy Land Farm, respectively. The overall 1actation yie1ds were 4586.13± 44.18 and 3003.47±28.31 k/g for Butana and Dairy Land Farms, respectively. Parity number had significant effects on lactation persistency in both Butana and Dairy Land Farms. Butana average lactation yield had a high1y significant (P<0.01) effect on lactation persistency compared to Dairy Land Farm. The effect of this trait, however, on lactation persistency as calculated by P3:3 model was not statistically significant in the Dairy land Farm. The correlation coefficient between calving interval and lactation persistency for the first four lactations in Butana and Dairy Land Farms was significant ( P<0.05) based on P3:3 model in Dairy Land Farm. No significant (P<0.05) effect was observed of average lactation yield for 180 days on 1actation persistency except in Butana Farm when calcu1ated by the Pm model. On the other hand the overall correlation coefficients between average lactation yield and average yield for 180 days for the first four lactations were 0.9214 and 0.9004 for Butana and Dairy Land Farms, respectively. The overall conflation coefficients between 1actation persistency and average yield for 180 days for the first four lactations were 0.2984, 0.18123, 0.09679, 0.5399 for PM and P3:3 mode1s in Butana and Dairy Land Farms, respectively. The overall corre1ation coefficients between calving interval and average lactation yield for the first four 1actations were 0.58467 and 0.34996 for Butana and Dairy Land Farms, respectively. In Butana Farm, the correlation coefficients between season of calving and 1actation persistency were highly significant (P<0.01) in wet summer and dry summer calvers, while for Dairy Land Farm the correlations were found to be significant (P <0.0 I) in winter calvers only.
URI: http://khartoumspace.uofk.edu/handle/123456789/14367
Date: 2015-06-23


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