الفهرس 
Cover Page Title in EnglishOnly 14 pages are availabe for public view
 |  | from | 87 |  |  |
| | | from | 87 | | |
Abstract
This study was performed between July 2011 and May 2012 and aimed to estimate the effects of administration of some hormonal treatments on parameters measuring the fertility of postpartum Holstein dairy cows. A total number of 67 Holstein dairy cows of mixed parity belonging to Milk production project (Agriculture Researches Station in Abis) Faculty of Agriculture –Alexandria University that is located at kilo 9-Alexandria-Cairo Agriculture Road. The cows were healthy and normal parturated. The herd fed a total mixed ration that was formulated on the basis of production and parity of cows. Estrus was detected by observation day and night, and estrus was confirmed by careful rectal palpation. The cows in estrus were clinically normal genitalia with normal estrus mucus, clear, viscus, not watery, not turbid, no pus flakes. The cows were inseminated toward the end of estrus with proved quality semen, and then the cows were examined for pregnancy diagnosis at sixty days post insemination.
A total number of 67 cows were randomly assigned to four groups:
The first group: Fourteen animals in this group were injected intramusculary with 50IU oxytocin (5 ml Oxytocin) within 2 hours after parturition.
The second group: Twelve cows in this group were injected intramusculary with 5 mg estradiol benzoate (1 ml Folone) within 2 hours after parturition.
The third group: Twenty cows in this group were injected intramusculary with 5 mg estradiol benzoate (1 ml Folone) within 2 hours after parturition followed by another injection with 5 mg estradiol benzoate (1 ml Folone) at 14 days of parturition.
The fourth group: Twenty one cows in this group left without treatment (control animals)
All data collected including information concerning date of calving, veterinary diagnosis and treatment, estrus detection and insemination and pregnancy diagnosis were entered directly into computer data base. from this information, we estimated the parameters measuring fertility which used to measure the reproductive performance.
The results obtained from the present study revealed that the days to first observed estrus in cows that received oxytocin was longer than the days to first estrus that observed in animals injected with other treatments but lower than control.
The days to first insemination after administration of double dose of estrogens was significantly (p<0.05) shorter than days to first insemination in other treated group and control group.
The shortest days open (80.10±2.66) was noted in cows treated with double dose of estrogen, the days open in oxytocin treated group (105.07±5.55) was longer than single dose of estrogen treated group and those obtained in double dose of estrogen treated group, but the days open in control group were longer than days open in any other treated group.
The difference was significant (p<0.05) between days open in different treated groups in comparison to control group. Also their was a significant difference between both of single and double treated groups with estrogen when compared to oxytocin treated group.
Their was non significant difference in number of services per conception among different treated groups and control group, the highest number of services per conception (2.43±0.22)in control group and the lowest number of services per conception (2.00±0.18)in double dose of estrogen treated group , so the difference was non significant.
The highest percentage of conception rate was obtained in double dose of estrogen treated group (30%) while the lowest percentage of conception rate was observed in single dose of estrogen treated group (16.67%) in comparison to oxytocin treated group (21.43%) and in control group (19.05%) , the difference was non significant.
The highest percentage of pregnancy rate (94%) was obtained in both single and double dose of estrogen treated group and the percentage of pregnancy rate in oxytocin treated group (71.43%) was better than control group (33.33%), the difference was highly significant among different groups.
Although the percentage of retained placenta in oxytocin treated group (14.29%) ,while in single treated group with estrogen (16.67%) ,and in double treated group with estrogen(20.00%) when compared to control group (38.10%), the difference was non significant.
The highest amount of milk production was obtained in oxytocin treated group (27.51±1.35) and the lowest amount of milk production was obtained in double dose of estrogen treated group (24.31±1.39) in comparison to amount of milk production in control group (25.98±0.99) and single dose of estrogen treated group (26.90±0.87), the difference was non significant.
Generally ,an improvement in reproductive performance was occurred after administration of small dose of estradiol benzoate (5mg) within two hours after parturition followed by another small dose of estradiol benzoate (5mg) at 14 days after parturition than any other results obtained in different treated groups of single dose of estrogen treated group , oxytocin treated group and control group.