Study of short lactation in Sahiwal cattle at organized farm
| Autor: | U. S. Narwaria, R. K. Mehla, K. K. Verma, S. S. Lathwal, Rajnarayan Yadav, A. K. Verma |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Veterinary World, Vol 8, Iss 5, Pp 690-694 (2015) |
| Druh dokumentu: | article |
| ISSN: | 0972-8988 2231-0916 |
| DOI: | 10.14202/vetworld.2015.690-694 |
| Popis: | Aim: The aim was to study the associated factors and extent of short lactations in Sahiwal cattle maintained under organized herd. Materials and Methods: The present study was conducted on Sahiwal cattle (n=530), utilizing 1724 lactation records with respect to lactation length (LL), spread over a period of 15 years (1997-2011), maintained at Livestock Research Center, National Dairy Research Institute, Karnal. Observations of LL were analyzed by descriptive statistical analysis in order to know the extent of short lactation of animals in the herd. Paternal Half sib method was used to estimate the genetic parameters, i.e., heritability, genetic, and phenotypic correlation. The influence of various non-genetic factors (season of calving, the period of calving, parity, type of calving, and season of drying) on LL was studied by least squares analysis of variance technique. Results: The least squares means for LL was found to be 215.83±3.08 days. Only 32.48% of total lactation records were fell in the range of 251-350 days of LL, while more than three-fourth (76%) of total observations were failed to reach the standard level of 305 milking days. LL class ranges from 251 to 300 days accommodated maximum number of observations (19.2%). The heritability estimate of LL was 0.22±0.07. Positive correlations were found between LL and service period, LL and 305 or less days milk yield, LL and calving interval; whereas dry period was negatively correlated with the LL. The least squares analysis had shown that LL was significantly (p |
| Databáze: | Directory of Open Access Journals |
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