245 Prenatal Transportation Stress Does Not Impact Ovarian Follicle Count in Brahman Offspring

Calves from transported dams had greater concentrations of plasma cortisol when restrained and cleared plasma cortisol at a slower rate than calves from non-transported dams. Considering this hypothalamic-pituitary-adrenal axis effect, investigation of other parameters influencing reproduction is warranted in offspring exposed to prenatal transportation stress. The purpose was to determine impact of prenatal transportation stress on offspring ovarian follicle count. Brahman cows were transported for 2 h on d 60, 80, 120, and 140 (± 5 d) of gestation. Offspring from transported (Stressed, n = 19) or non-transported (Control, n = 15) dams were slaughtered at 5 yr (Replication 1, n = 14) or ovariectomized at 8 yr (Replication 2, n = 20). A cross-section of ovary was collected, serially sectioned, and stained. Numbers of total, primordial, primary, secondary, and antral follicles were determined per section. Total ovarian follicle count for each stage was calculated using ovary dimensions. The MIXED procedure of SAS was used to analyze ovarian follicle count with treatment, replicate, and the interaction as fixed effects. Total ovarian follicle count decreased with age (P < 0.01; R1 = 383,663, R2 = 154,560); however, there was no difference in total ovarian follicle count between offspring due to treatment (P = 0.17; S = 221,813, C = 316,409). Similarly, there was no difference in primordial (P = 0.22; S = 127,300, C = 188,304), primary (P = 0.28; S = 58,610, C = 77,237), or antral (P = 0.48; S = 23,202, C = 28,695) follicle count between offspring due to treatment. Fewer secondary follicles were observed in Stressed offspring compared to Control offspring (P = 0.03). These results suggest that the ovarian follicular reserve, AFC, and potential fertility of cows may not be impacted by exposure to prenatal transportation stress. USDA is an equal opportunity provider and employer.

282 Nutritional Monitoring of Prenatally Stressed and Translocated Brahman Heifers

One drought mitigation strategy is transporting livestock to non-drought locations. Our objective was to evaluate the effects of prenatal stress and translocation on growing Bos indicus heifers. Twelve heifers born in spring 2019 at Overton, TX (1245 mm annual precipitation) were transported ~700 km to Sonora, TX (610 mm annual precipitation) in April 2020. Six heifers (283±10 kg) were born to dams subjected to transportation stress during mid-gestation (PNS) and 6 (279±17 kg) were born to non-stressed dams (CON). Heifers grazed a series of 24-ha native range pastures (aboveground forage biomass; 1508±390 kg/ha) and were sampled (non-shrunk BW/BCS score, feces) at 2-wk intervals from May through September. Fecal samples were collected from the ground or the rectum of each animal and stored at -20o C until processed for near infrared spectroscopy (NIRS) and prediction of diet crude protein (CP) and digestible organic matter (DOM). Inputs to a grazing animal nutrition model for prediction of BW included diet CP and DOM, age, and weather. Differences between groups for BW and nutritional parameters were determined by analysis of variance or paired t-test. Both groups gained BW (22±4 kg) throughout the study, there were no differences (P > 0.1) due to treatment. Diet CP and DOM were affected by date (P < 0.01) as diet quality declined from spring to fall. Percent diet CP was greater (P < 0.05) in PNS than CON, especially during July and August (6.94±0.10 vs 6.23±0.17, respectively). Corresponding values for diet DOM were (59.53±0.55 vs 59.14±0.43, respectively; P = 0.09). Observed vs model-predicted weight was different (P < 0.05) for both groups when using CP-based outputs, but not when using metabolizable protein-based outputs (P > 0.1). In summary, PNS heifers selected a diet of greater CP than CON, and tended to select a diet greater in DOM.

Small RNA-Seq Analysis Reveals miRNA Expression of Short Distance Transportation Stress in Beef Cattle Blood

Transportation is a crucial phase in the beef cattle industry, and the annual losses caused by beef cattle transport stress are substantial. Because of its huge economic losses, such as lower growth rate and even death, long-distance transportation stress has attracted more attention from beef production practitioners because of its huge economic losses. Compared with the long-distance transportation stress, the short-distance transportation stress was ignored for the reason of no obvious symptoms in cattle. Our previous study showed that the disorder of B cell function could be a potential health risk after short-distance transportation. However, the transcriptome details of the changes in the cattle blood after short-distance transportation and the molecular mechanisms for the regulation of the developmental process are not clearly known. In this study, a total of 10 Qinchuan cattle were used to compare the molecular characteristics of blood before and after short-distance transportation. The miRNA-seq showed that 114 differentially expressed miRNAs (DEMs) were found (40 upregulated and 74 downregulated) between two groups before and after transportation. Furthermore, more than 90% of the miRNAs with counts of more than 10 were used to construct a co-expression network by weighted correlation network analysis (WGCNA), and four independent modules were identified. According to their relationship with 30 hub genes, the turquoise module was the key module in this study. The regulator network of hub genes and miRNAs in the turquoise module was constructed by miRNAs targeting genes predicting, and the miRNAs had targeting sites within hub genes that could be identified as hub-miRNAs. Further, it showed that CD40 and ITPKB had the same targeting miRNAs (miR-339a/b), and the newly discovered hub miRNAs filled the gaps in our previous study about the relationship between hub genes in short-distance transportation stress and provided the potential utility for predicting and treatment of short-distance transportation stress in beef cattle.

Evaluation of Prenatal Transportation Stress on the Number of Pituitary Corticotrophs in Mature Brahman Cows

Prenatal transportation stress (PNS) results in calves that are more temperamental and have greater circulating concentrations of cortisol compared to control calves. The objective of this experiment was to evaluate whether PNS alters the number of pituitary corticotrophs in mature Brahman cows. We hypothesized that the increased circulating cortisol concentrations previously characterized in this bovine model is associated with developmental changes in the anterior pituitary leading to an increased number of corticotrophs. Pregnant Brahman cows (n = 48) were transported in trailers for 2-hour periods at 60±5, 80±5, 100±5, 120±5, and 140±5 days of gestation. Non-transported pregnant cows (n = 48) were designated as the Control group. Control and PNS offspring heifers were managed together under the same environmental conditions. At approximately 5 yr of age, randomly selected non-pregnant cows (Control, n = 8; PNS, n = 6) were humanely harvested and the whole pituitaries were collected. Pituitaries were weighed, fixed in paraformaldehyde, serially dehydrated with graded ethanol, embedded in paraffin blocks, and cut into 5-μm sections. Immunohistochemistry was performed to detect cells expressing adrenocorticotropic hormone (ACTH) as a marker for corticotrophs. Three comparable sections from the midsagittal plane from each animal were processed using an ovine ACTH-specific antibody (Dr. A.F. Parlow, NIDDK). Five fields of view were analyzed per section (15 fields per animal). Anterior pituitary gland weight did not differ (P > 0.10) between groups (Control = 2.11 ± 0.12 g; PNS = 2.10 ± 0.15 g). The mean number of ACTH-positive cells between control (531±56 cells/section) and PNS cows (477±49 cells/section) also did not differ (P > 0.10). In conclusion, the number of pituitary corticotrophs in mature Brahman cows was not affected by prenatal transportation stress and is likely not a mechanism mediating the increased circulating cortisol concentrations seen in this bovine model of fetal programming.

Transcriptome Characterization of Short Distance Transport Stress in Beef Cattle Blood

The transportation is a crucial phase in beef cattle industry, and the annual losses caused by beef cattle transport stress are substantial. Several studies have described the effect of long distance transportation stress on animal health, such as disorder in nervous, endocrine, immune, and metabolic system. However, molecular mechanisms underlying short distance transportation stress is still poorly understood. Present study aims to investigate the effect of short distance transportation by measuring the hematological indices and transcriptomic analysis. In this study, a total 10 Qinchuan cattle were used to compare the molecular characteristics of blood before and after transportation. We have found that a stress-related marker “white blood cell count (WBC)” increased significantly after transportation. The decrease in triglyceride (TG), cholestenone (CHO), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) showed that energy expenditure was increased after transportation, but not enough to activate fatty decomposition. Intriguingly, the decrease of malondialdehyde (MDA) showed that cattle were more resilience to oxidative stress. The RNA-seq showed that 1,092 differentially expressed genes (DEGs) were found (329 up-regulated and 763 down-regulated) between group before and group after. The GO and KEGG enrichment showed that the metabolic pathway and B cell function related pathways were enriched. Furthermore, median absolute deviation (MAD) top 5,000 genes were used to construct a co-expression network by weighted correlation network analysis (WGCNA), and 11 independent modules were identified. Combing with protein-protein interaction (PPI) analysis, the verification of quantitative real-time PCR (qPCR) and the correlation of B cell function, structural maintenance of chromosomes 3 (SMC3), jun proto-oncogene (JUN), and C-X-C motif chemokine ligand 10 (CXCL10) were suggested as potential molecular markers in identification of short distance transportation. Collectively, the blood RNA-seq analysis and WGCNA indicated that the disorder of B cell differentiation, proliferation, survival, and apoptosis were the potential molecular mechanism in short distance transportation stress. In conclusion, our results provide the novel insight about potential biomarkers for short distance transportation stress, which may serve as for diagnosing and preventing this condition in beef industry.