Effect of two superovulation treatments on subsequent fertility in the confined dairy cow
| Autor: | A.J. Hackett, A.J. McAllister |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
medicine.medical_specialty
Equine Superovulations media_common.quotation_subject Fertility Embryo Biology Crossbreed Follicle-stimulating hormone Regimen Endocrinology Animal science Food Animals Internal medicine medicine Animal Science and Zoology Reproduction Small Animals Dairy cattle media_common |
| Zdroj: | Theriogenology. 38(5) |
| ISSN: | 0093-691X |
| Popis: | During a 13-month period, 64 lactating dairy cows of 2 genetic lines, Holstein and crossbred, housed indoors year-round were subjected to 2 superovulations and embryo collections within 112 days post partum. Half of the follicle stimulating hormone (FSH) treatments were given in a descending dosage regimen (Treatment A; 6.5 mg, 5.5 mg, 4.5 mg, and 3.5 mg, twice a day, total 40 mg) over 4 days; the remaining half of the treatments were administered in a constant dosage regimen (Treatment B) of 5 mg twice a day over 4 days. There were no significant differences due to treatment in the number of cows stimulated (more than 2 corpora lutea) nor in the number of ova/embryos collected. However, embryos were obtained from more cows (P0.05) when treated with the descending dosage regimen. More cows (P0.05) were stimulated by the superovulatory treatment during the first period than during the second period regardless of the regiment used, treatment A or B. More embryos (P0.05) were obtained from the Holstein line than from the crossbred line. Fifty-two cows were inseminated at least once after the second embryo collection. Overall, 41 cows (79%) became pregnant after the second collection, requiring up to 4 services. These results suggest that the reproduction of dairy cattle housed indoors year-round is not adversely affected by 2 superovulation treatments and embryo collections within 112 days post partum. The question as to whether the administration of FSH is more efficacious in a descending dosage regimen or a constant dosage regimen was not resolved. |
| Databáze: | OpenAIRE |
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