Studies on the Peak Yield and Persistency of Lactation in Crossbred dairy cows
By: Girija CR.
Contributor(s): Krishnan Nair B R (guide).
Material type:
BookPublisher: Mannuthy Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences 1980DDC classification: 636.082 Online resources: Click here to access online Dissertation note: MVSc Abstract: With the objective of studying the peak yield, persistency, their relation with other production traits and the shape of the lactation curves, the data on the production and reproduction records of 298 Jersey x Zebu and 69 Brown Swiss x Zebu crossbred cows maintained at Livestock farms of Kerala Agricultural University were utilized. Persistency was calculated as a ratio of the yield from the attainment of peak yield to the 305 days yield and the yield upto the peak yield.
The means of lactation yield upto 305 days were 1411.23 + 32.38 kg and 1453.2 + 77.89 kg respectively in Jersey and Brown Swiss crossbreds. The days to attain peak yield were 44.75 +1.23 days and 49.86 + 3.06 days in Jersey and Brown Swiss crossbreds respectively. The respective means of peak yield in Jersey and Brown Swiss crossbreds were 7.91 + 0.15 kg and 7.70 + 0.31 kg. The persistency indices in Jersey x Zebu and Brown Swiss x Zebu crossbreds were 5.2 + 0.30 and 4.18 + 0.15 respectively. Season of calving, farm, year of calving and age at first calving had no significant effect on persistency index with the exeption of farm in the case of Brown Swiss crossbreds.
There were highly significant positive correlation between peak yield and total lactation yield and 305 days yield. But the correlations between peak yield and lactation period was significant in Jersey crossbreds but not in Brown Swiss crossbreds. Correlation between persistency and lactation period, peak yield and 305 day’s yield were highly significant in the case of Brown Swiss crossbreds but the same were non significant in Jersey crossbreds.
The lactation curves revealed that following parturition the lactation yield sharply increased upto the 3rd week and then rose to a maximum by 7th week. The level was maintained upto 9th week and after which the production declined. The rates of decline were 1.9 per cent and 1.7 per cent respectively in Jersey x Zebu and Brown Swiss x Zebu crossbreds.
Thus it can be concluded that the characteristic of good milk production potential, early attainment of peak yield, substantial persistency and the highly positive correlation of peak yield with 305 day’s yield in the Jersey x Zebu and Brown Swiss x Zebu crossbreds make them quite suitable for adoption in Kerala.
| Item type | Current location | Call number | Status | Date due | Barcode |
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Theses
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KAU Central Library, Thrissur Theses | 636.082 GIR/ST (Browse shelf) | Available | 170087 |
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MVSc
With the objective of studying the peak yield, persistency, their relation with other production traits and the shape of the lactation curves, the data on the production and reproduction records of 298 Jersey x Zebu and 69 Brown Swiss x Zebu crossbred cows maintained at Livestock farms of Kerala Agricultural University were utilized. Persistency was calculated as a ratio of the yield from the attainment of peak yield to the 305 days yield and the yield upto the peak yield.
The means of lactation yield upto 305 days were 1411.23 + 32.38 kg and 1453.2 + 77.89 kg respectively in Jersey and Brown Swiss crossbreds. The days to attain peak yield were 44.75 +1.23 days and 49.86 + 3.06 days in Jersey and Brown Swiss crossbreds respectively. The respective means of peak yield in Jersey and Brown Swiss crossbreds were 7.91 + 0.15 kg and 7.70 + 0.31 kg. The persistency indices in Jersey x Zebu and Brown Swiss x Zebu crossbreds were 5.2 + 0.30 and 4.18 + 0.15 respectively. Season of calving, farm, year of calving and age at first calving had no significant effect on persistency index with the exeption of farm in the case of Brown Swiss crossbreds.
There were highly significant positive correlation between peak yield and total lactation yield and 305 days yield. But the correlations between peak yield and lactation period was significant in Jersey crossbreds but not in Brown Swiss crossbreds. Correlation between persistency and lactation period, peak yield and 305 day’s yield were highly significant in the case of Brown Swiss crossbreds but the same were non significant in Jersey crossbreds.
The lactation curves revealed that following parturition the lactation yield sharply increased upto the 3rd week and then rose to a maximum by 7th week. The level was maintained upto 9th week and after which the production declined. The rates of decline were 1.9 per cent and 1.7 per cent respectively in Jersey x Zebu and Brown Swiss x Zebu crossbreds.
Thus it can be concluded that the characteristic of good milk production potential, early attainment of peak yield, substantial persistency and the highly positive correlation of peak yield with 305 day’s yield in the Jersey x Zebu and Brown Swiss x Zebu crossbreds make them quite suitable for adoption in Kerala.
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