Postpartum ovarian activity in Sahiwal - Friesian cows fed different levels of energy
Postpartum ovarian function was determined by milk progesterone radioimmunoassay in 21 first-calf Sahiwal-Friesian cows assigned to one of three treatment groups designated as low, medium and high energy levels (n=7). The progesterone concentrations in defatted milk were determined thrice weekly...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
1984
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/85596/1/FPV%201984%201%20ir.pdf |
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| Summary: | Postpartum ovarian function was determined by milk
progesterone radioimmunoassay in 21 first-calf Sahiwal-Friesian
cows assigned to one of three treatment groups designated as
low, medium and high energy levels (n=7). The progesterone
concentrations in defatted milk were determined thrice weekly
for 120 days postpartum.
Mean interval to resumption of ovarian activity and to
forst ovulation was longest in the low energy group and shortest
in the high energy group. Using progesterone concentration
of > 1 ng/ml as criteria for corpus luteum activity, first ovulation
occurred at 37.7 ± 18.0,26.6;t 15.7and25.3 ± 8.4 days
for low, medium and high energy groups, respectively. However,
first estrus was observed at 28.0 ± 21.6, 32.7:t 9.8 arid 25.4:t
6.0 days, respectively. The percentages of silent estrus were
13.6 percent, 29.6 percent and 14.3 percent for low, medium and high energy groups, respectively, with a majority ( 46.7
percent) detected during the initial postpartum estrous cycle.
Interval to first insemination was longest in the low energy
group, being 68.6·± 10.3,62.6 ± 18.1 and 56.6 ± 8.1 days for
lOIN, medium and high energy groups, respectively. However,
services per conception were 1.1, 1.7 and 3.3, respectively.
Interval to conception was shortest in the low energy group,
being 74.3 ± 14.9, 79.1 ± 17.3 and 88.3 ± 30.4 days for low,
medium and high energy groups, respectively. The corresponding
first service conception rates were 85.7 percent, 42.9 percent
and 42.9 percent. Although a trend was detected, the differences
were not statistically significant (p> 0.05) between the
groups on the reproductive parameters analysed.
In summary, low energy intake may delay the resumption of
postpartum ovarian activity and ovulation in Sahiwal-Friesian
cows. Mean interval from calving to conception, however, was
not significantly different amongst the three groups if breeding
commenced after 60 days postpartum. A higher incidence of
silent estrus was detected during the initial estrous cycles
after calving. Lastly, milk progesterone radioimmunoassay is
a useful tool for estrus confirmation, early pregnancy diagnosis
and assessment of fertility in postpartum cows. |
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