Prenatal transportation stress did not impact ovarian follicle count for three generations of female Brahman offspring

Authors: QUAIL, LACEY - Texas A&M University; RANDEL, RONALD - Texas A&M Agrilife; WELSH, THOMAS - Texas A&M University; Cushman, Robert - Bob; Yake, Hannah; D'OREY BRANCO, RUI - Texas A&M Agrilife; NEUENDORFF, DONALD - Texas A&M Agrilife; LONG, CHARLES - Texas A&M Agrilife; PERRY, GEORGE - Texas A&M Agrilife

Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2022
Publication Date: 6/8/2022
Citation: Quail, L.K., Randel, R.D., Welsh Jr., T.H., Cushman, R.A., Yake, H.K., d'Orey Branco, R.A., Neuendorff, D.A., Long, C.R., Perry, G.A. 2022. Prenatal transportation stress did not impact ovarian follicle count for three generations of female Brahman offspring. Animal Reproduction Science. 243. Article 107016. https://doi.org/10.1016/j.anireprosci.2022.107016.
DOI: https://doi.org/10.1016/j.anireprosci.2022.107016

Interpretive Summary: During the first half of gestation, the ovarian reserve is established in the bovine fetal ovary. This is a time when pregnant cows may need to be transported due to inadequate feed resources. We investigated whether transporting pregnant cows in early pregnancy was detrimental to the number of follicles in the daughters' ovaries later in life. There were no differences in histological or ultrasonographic follicle counts in the ovaries of the daughters when transportation stress occurred between days 60 and 140 of pregnancy. This study indicates that pregnant cows can be transported in cases of inadequate feed resources after day 60 of pregnancy without negatively impacting the ovarian reserve of their daughters.

Technical Abstract: As prenatal transportation stress altered behavior and adrenal glucocorticoid secretion of calves, we hypothesized that prenatal transportation stress would decrease ovarian reserve size and negatively impact female offspring fertility. The impact of prenatal transportation stress on ovarian follicle numbers in female offspring for three generations was studied. Brahman cows were transported for 2 h on day 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 of gestation. Ovaries were collected from offspring of transported or non-transported dams at multiple ages. Primordial, primary, secondary, and antral follicles were histologically analyzed. Antral follicle numbers were determined by ultrasound in a subset of offspring. Numbers of primordial, primary, secondary, and antral follicles were analyzed using the MIXED procedure, while the CORR procedure of SAS was used to determine the correlation between follicles observed by ultrasonography and histology. There were no differences (P > 0.05) in the number of primordial, primary, secondary, antral, or total follicles observed histologically due to treatment. Younger females had significantly greater numbers of follicles than older females (P < 0.0001). Antral follicles tended to be correlated with total histological ovarian follicles (P = 0.10). There was no difference in the number of antral follicles observed at ultrasound due to treatment (P = 0.3147), or generation (P = 0.6005) when controlling for age at observation. These results show that short-term transportation stress during early- to mid-gestation did not impact fertility as measured by ovarian follicle numbers in female Brahman offspring for three generations.