engleski

Asymmetrical functional activities of ovaries and tubular part of reproductive organs of dairy cows

The aim of this study was to compare the effect of postpartal activity of the left and the right side of reproductive organs on subsequent fertility in dairy cows, depending on the side of previous gestation, after deep intracornual semen deposition, strictly in cows with single ovulations. The semen was deposited in the horn ipsilateral to the ovary with preovulatory follicle. The effects were studied in 2300 cows of Holstein-Friesian breed, out of which 937 (40.74%) were in their fifi rst lactation, 641 (27.87%) in their second, 417 (18.13%) in third and 305 (13.26%) in their fourth lactation. The fifi rst manifested oestrus occurred spontaneously in 2099 (91.26%) cows, while it was induced with the GPG (Ovsynch) method in 201 (8.74%) cows. The relationship between the sides of the previous gestation and the result of conception depending on the side of the ovulating ovary were compared. Signififi cantly stronger right side activity of the reproductive organs was registered in the previous gestation: 1321 (57.43%) of pregnancies were in the right horn and 979 (42.57%) in the left horn. After the involution of the uterus, there was increased activity of the side opposite to the previous gestation, and mature follicles were found on the contralateral ovary in 1377 (59.87%) cows and on the ipsilateral ovary in 923 (40.13%) cows. The difference in the sides of ovulating ovaries was statistically signififi cant, meaning that ovulations are more frequent on the ovary contralateral to the postpartal horn. These results signififi cantly suggest that the bilateral asymmetry of reproductive organs has an inflfl uence on conception rates in dairy cows. The results also confifi rm asymmetry in the function of the reproductive organs in dairy cows, due to differences in ovarian activity and probably even more because of physiological differences in the tubular part of the reproductive organs, depending on the side of previous gestation and involution of the postpartal horn of the uterus.

airy cattle; bilateral asymmetry; s dairy cattle; bilateral asymmetry; side of pregnancy; side of ovulation

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