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

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.

Evaluation of the effects of sire and dam calving group on age at first calving in Brahman heifers.

This study evaluated the possible effects of sire and dam calving groups on age at first calving in Brahman heifers. A total of 570 heifers born between the years 2004 and 2017 were exposed as yearlings to fertile bulls through time of pregnancy determination. A calving group was determined by calculating the mean (993 d) and standard deviation (187 d) of heifer age at first calving.

Influence of prenatal transportation stress-induced differential DNA methylation on the physiological control of behavior and stress response in suckling Brahman bull calves.

The objective of this experiment was to examine potential differential methylation of DNA as a mechanism for altered behavioral and stress responses in prenatally stressed (PNS) compared with nonprenatally stressed (Control) young bull calves. Mature Brahman cows (n = 48) were transported for 2-h periods at 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 d of gestation (Transported group) or maintained as nontransported Controls (n = 48). From the offspring born to Transported and Control cows, a subset of 28-d-old intact bulls (n = 7 PNS; n = 7 Control) were evaluated for methylation of DNA of behavior and stress response-associated genes.

Prenatal transportation stress alters genome-wide DNA methylation in suckling Brahman bull calves.

The objective of this experiment was to identify genome-wide differential methylation of DNA in young prenatally stressed (PNS) bull calves. Mature Brahman cows (n = 48) were transported for 2-h periods at 60 ± 5, 80 ± 5, 100 ± 5, 120 ± 5, and 140 ± 5 d of gestation or maintained as nontransported Controls (n = 48). Methylation of DNA from white blood cells from a subset of 28-d-old intact male offspring (n = 7 PNS; n = 7 Control) was assessed via reduced representation bisulfite sequencing.

Relationships between numbers of antral follicles and postpartum interval in Brahman females.

To determine relationships of ovarian antral follicle count (AFC) on d 28 postpartum with postpartum interval (PPI) and AFC on d 8 post-estrus, three-dimensional ultrasonography was performed on multiparous (n = 47) and primiparous (n = 20) Brahman cows on d 28 postpartum and on d 8 post-estrus. Follicles were evaluated to determine numbers of total, small (≤17 mm), medium (17 mm-67 mm), and large follicles (≥67 mm) on each ovary. Estrus was detected using vasectomized, penile-deviated bulls fitted with chin-ball markers during the AI period and with tail paint during the natural service period.