Short communication: suppression of estrous cycles in lactating cows has no effect on milk production
| Autor: | Pierre Lacasse, L. Delbecchi |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Involution (mathematics)
medicine.medical_specialty Deslorelin Ice calving Estrous Cycle Lactose Biology Fats Gonadotropin-Releasing Hormone chemistry.chemical_compound Animal science Internal medicine Lactation Genetics medicine Animals Mammary gland involution Dairy cattle Progesterone Estrous cycle Drug Implants Triptorelin Pamoate Estradiol food and beverages Milk Proteins medicine.anatomical_structure Endocrinology Milk chemistry Animal Science and Zoology Cattle Female Food Science |
| Zdroj: | Journal of dairy science. 89(2) |
| ISSN: | 1525-3198 |
| Popis: | The decline in milk yield observed after peak production in dairy animals results from apoptotic death of mammary epithelial cells. In cows, this decrease in milk yield can be accelerated by injection of 17beta-estradiol, thus evoking a possible role of estrogens in the regulation of bovine mammary gland involution. In nonpregnant cows, mammary involution could be induced or enhanced by the return of estrous cycles and the accompanying cyclic peaks of estrogen concentration in the serum of lactating animals. To test this hypothesis, we inserted implants of a GnRH agonist, deslorelin, in an ear of each cow (n = 10) on d 10 and 100 of lactation, to temporarily suppress the return of ovarian cycles. Cows were studied from calving to d 210 of lactation. Deslorelin had no impact on feed intake or animal health. Deslorelin significantly reduced serum concentrations of 17beta-estradiol and progesterone as compared with untreated cows (n = 10). Deslorelin had no effect on milk fat and protein, whereas milk lactose content was lower in treated cows than in control cows on d 100 of lactation. Finally, there was no difference in milk production between the 2 groups of cows. These results are consistent with previous observations that showed that delaying estrous cycles after calving had no effect on milk yield and they extend those observations to late lactation. Based on milk production data, the estrogen profiles associated with recurring estrous cycles apparently do not cause bovine mammary tissue to undergo gradual involution. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|