Evaluation of production and growth performance of AI heifers under the Kerala heifer calf rearing programme
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Date
1998-11-07
Authors
Silva, L. P.
Dematawewa, C. M. B.
Ibrahim, M. N. M.
Jagath, K. K.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
Artificial Insemination (AI) is the most widely used tool in improving dairy
stock in Sri Lanka since 1950's. The present study was conducted with the aim of
evaluating the production and growth performance of AI crossbred heifers. The
animals for this study were selected from the Kerala Heifer Calf Rearing programme
which was launched by the department of Animal Production and Health with the
objectives of increasing productivity (by inducing early sexual maturity) and reducing
mortality of AI female calves through proper feeding and management.
A set of 150 heifers registered under the Kerala scheme in North Western
Province were considered in the study. Secondary data on production records and
breeding records were analyzed. Primary data were collected from selected recipients
of the programme by conducting a field survey.
The results of the present study revealed that the average age at sexual maturity
of all the heifers studied was 15.38 ± 2.97 months which is less than half of the age
that an AI heifer would reach sexual maturity under normal circumstances. Pattern of
growth showed that this age coincides with the peak growth rate of the heifers in most
instances. The age at sexual maturity of the heifers was shown to vary with the
paternal breed of the animal (where the maternal breed was predominantly nondescript
coming from the local population). The average age at first calving was 26.89 ± 2.82
months. Accordingly, the average age at conception of these heifers was 17.89 ± 2.82
months.
Rate of growth varied among heifers according to their age categories (66 - 685
g / day). The growth rates at different age categories, namely 1-6 months, 7-12 months
and 13-24 months were compared with the standard rates of growth. Finally, a standard
growth curve has been fitted for all the heifers before and after conception to separate
the pre- and post-embryonic growth patterns of calves under the Kerala scheme.
According to the results, it can be suggested that the objectives of the Kerala
Heifer Calf Rearing Programme have been achieved. However, the actual production
performance (during economical life time) of these heifers yet to be evaluated.
Description
Keywords
Kerala , Calf , Artificial insemination , Agriculture and animal sciences
Citation
Proceedings & Abstracts of the Annual Research Sessions November 07, 1998,University of Peradeniya,Peradeniya, Sri Lanka,pp.06