Effects of Exogenous Glucocorticoid Infusion on Appetitic Center Development in Postnatal Dairy Bull Calves.

The objective of this study was to determine the effects of exogenous glucocorticoid administration on leptin concentrations and brain development markers, such as protein and hypothalamic gene expression, in dairy bull calves. Within 4 h of parturition, Holstein bulls were intravenously infused with either a low cortisol dose (LC; n = 9, 3.5 µg/kg of body weight (BW)), high cortisol dose (HC; n = 9, 7.0 µg/kg BW), or control (CON; n = 9, saline) dose, with a 2nd infusion 24 h postpartum. Jugular blood was collected prior to infusion and daily until the calves were euthanized (day 5). Cerebrospinal fluid (CSF) from the third ventricle and adipose (omental, perirenal, and mesenteric) and hypothalamic tissue were collected. The blood and CSF samples were analyzed for leptin concentrations. The data were analyzed using SAS. Serum (p = 0.013) and CSF (p = 0.005) leptin concentrations in HC- and LC-treated calves were decreased compared with CON-treated calves. Leptin protein expression was decreased (p < 0.044) in perirenal and omental adipose tissue of LC-treated calves compared with CON-treated calves. Gene abundance of brain-derived neurotrophic factor and fibroblast growth factors 1 and 2 were decreased (p < 0.006) in HC- and LC-treated calves compared with CON-treated calves. In summary, cortisol administered to dairy bull calves reduced leptin concentrations, decreased leptin protein expression in perirenal and omental adipose tissue, and altered gene expression in hypothalamic tissue.

Segmental aneuploid hotspots identified across the genome concordant on reanalysis.

The aim of this study was to characterize a large set of full segmental aneuploidies identified in trophectoderm (TE) biopsies and evaluate concordance in human blastocysts. Full segmental aneuploid errors were identified in TE biopsies (n = 2766) from preimplantation genetic testing for aneuploid (PGT-A) cycles. Full segmental deletions (n = 1872; 66.1%) presented twice as many times as duplications (n = 939; 33.9%), mapped more often to the q-arm (n = 1696; 61.3%) than the p-arm (n = 847; 31.0%) or both arms (n = 223; 8.1%; P < 0.05), and were eight times more likely to include the distal end of a chromosome than not (P < 0.05). Additionally, 37 recurring coordinates (each ≥ 10 events) were discovered across 17 different chromosomes, which were also significantly enriched for distal regions (P = 4.1 × 10-56). Blinded concordance analysis of 162 dissected blastocysts validated the original TE PGT-A full segmental result for a concordance of 96.3% (n = 156); remaining dissected blastocysts were identified as mosaic (n = 6; 3.7%). Origin of aneuploid analysis revealed full segmental aneuploid errors were mostly paternally derived (67%) in contrast to whole chromosome aneuploid errors (5.8% paternally derived). Errors from both parental gametes were observed in 6.5% of aneuploid embryos when multiple whole chromosomes were affected. The average number of recombination events was significantly less in paternally derived (1.81) compared to maternally derived (3.81) segmental aneuploidies (P < 0.0001). In summary, full segmental aneuploidies were identified at hotspots across the genome and were highly concordant upon blinded analysis. Nevertheless, future studies assessing the reproductive potential of full (non-mosaic) segmental aneuploid embryos are critical to rule out potential harmful reproductive risks.

Effects of postweaning supplementation of immunomodulatory feed ingredient on circulating cytokines and microbial populations in programmed fed beef heifers.

The objective was to determine the effects of an immunomodulatory feed ingredient following weaning on cytokine expression and fecal microbial populations of heifers. Commercial Angus heifers (n = 72) were weaned (227 ± 7 d of age), blocked by BW (n = 9 blocks), and randomly assigned to one of two pens per block. Pens within weight block (four heifers per pen) were then randomly assigned to treatments. Heifers were fed twice daily from days 0 to 60 (to gain 0.75 kg/d) and top dressed with either 18 g/heifer/d of the immunomodulatory feed ingredient (Celmanax; Arm and Hammer Animal Nutrition, Princeton, NJ; CEL) or corn-germ meal (CON). Blood samples were collected on days 0, 15, 30, 45, 60 and fecal grab samples on day 0 of the feeding trial. After day 60, two heifers per pen (n = 32) were randomly selected for a transportation challenge. Serum samples were collected at hours 0, 4, 8, 12 and fecal grab samples at hours -24, 0, 24 and 7 d postchallenge. Blood samples were analyzed for interferonγ (IFNγ), interleukin-8 (IL-8), and haptoglobin (HP) using commercially available ELISA kits and qRT-PCR for genes of interest associated with cytokine expression. Fecal samples were enumerated for Clostridia and E. coli using selective media (≤5 isolates from each media/sample), tested to determine whether they were Clostridium perfringens or pathogenic E. coli, and then enriched for detection of Salmonella. Data were analyzed via ANOVA. During the feeding trial, HP was reduced (P = 0.018) in CEL compared with CON at days 15, 45, and 60, whereas IFNγ and IL-8 did not differ (P > 0.080) between treatments. All cytokines were decreased (P < 0.001) in CEL compared with CON during the challenge. During the feeding trial, HP mRNA was increased (P = 0.045) in CEL compared with CON at days 30 and 60. Similarly, IFNγ mRNA was increased (P = 0.040) in CEL compared with CON; however, other genes of interest did not differ (P > 0.172). Both C. perfringens and total E. coli counts were decreased (P = 0.036) in CEL compared with CON at 24 h after the start of the transportation challenge. Clostridia and pathogenic E. coli counts did not differ (P = 0.941) between treatments. Total Clostridia and E. coli counts were increased (P < 0.014) 24 h postchallenge. All microbial populations, except pathogenic E. coli, observed decreased (P ≤ 0.009) counts from 24 h to 7 d postchallenge. Overall, Celmanax supplementation decreased circulating cytokines, and altered microbial populations and gene expression, thus, may serve a role in preparing animals to better cope with immunological challenges.

With consumers wanting less antibiotic usage in cattle production, the need for natural feed ingredients that have positive effects on animal health are needed. The feeding of a yeast-based feed product decreased cytokines in the blood and their mRNA expression in white blood cells that act on stimulating an inflammatory response. When an animal has an inflammatory response, their immune system is working harder than necessary. This means they are using energy that could otherwise be used for growth, which decreases efficiency and performance. The feeding of this yeast-based feed ingredient also reduced the amount of harmful bacteria in the feces of the heifers. Having lower amounts of harmful bacteria (such as Salmonella) in the feces decreases the chance of carcass contamination. For consumers, this means less instances of food-borne illnesses.

Oxylipin concentrations in bovine corpora lutea during maternal recognition of pregnancy.

The objective was to determine the effects of pregnancy status on oxylipin profiles and eicosanoid metabolizing enzymes and in corpora lutea (CL) or endometrial (caruncle; CAR and intercaruncle; IC) tissues. Angus crossed cattle were synchronized with the CO-Synch protocol and artificially inseminated (AI). Sixteen days after AI, cattle were euthanized, and reproductive tracts collected from 6 non-pregnant and 6 pregnant cows. Oxylipin profiles and concentrations of progesterone (P4) were obtained from CL tissues. The activity of cytochrome P450 1A (CYP1A) and UDP-glucuronosyltransferase (UGT) enzymes were determined using specific luminogenic substrates. Data were analyzed using the MIXED procedure of SAS, and the model included pregnancy status. Corpora lutea of pregnant cattle contained greater (P < 0.05) concentrations of 9,10-DiHODE, 15,16-DiHODE, and 9,10-DiHOME. These oxylipins have been observed to increase cellular proliferation and vasodilation. Activity of CYP1A in the CL and UGT in CAR and IC was not different (P > 0.05) between pregnant and non-pregnant cattle. In the CL, activity of UGT was decreased (P < 0.05) in pregnant vs. non-pregnant cattle. The decrease in CL UGT activity during pregnancy indicates alterations in local hormone metabolism, while no differences in CL weight nor amount of P4 in CL were different between pregnant and non-pregnant cattle. Moreover, the increase in specific concentrations of oxylipins in the CL may indicate a novel pathway of steroid and eicosanoid metabolism during maternal recognition of pregnancy.

Effect of chronic melatonin supplementation during mid to late gestation on maternal uterine artery blood flow and subsequent development of male offspring in beef cattle.

The objective of the current study was to examine the effects of supplemental melatonin implants on uterine artery blood flow from mid to late gestation in beef cattle and subsequent development of their male offspring. Commercial beef heifers (n = 32) and cows (n = 25) were bred via artificial insemination and assigned to 1 of 2 groups supplemented with melatonin implants (MEL) or without (CON) at day 180, 210, and 240 of gestation. Uterine artery blood flow was determined using color Doppler ultrasonography. A subset of 12 crossbred heifers (n = 6 MEL; n = 6 CON) underwent Cesarean sections on day 243 ± 2 of gestation to allow for placentome collection. Maternal and fetal serum were collected to analyze melatonin concentrations. The remaining cattle were allowed to calve and at weaning (195 ± 2 d of age), bull calves (n = 15) were castrated and testicular tissue harvested for seminiferous tubule analysis. Heifer uterine artery blood flow was increased (P = 0.009) at day 240 of gestation in MEL compared with CON heifers. Cow uterine artery blood flow was increased (P = 0.003) in MEL compared with CON cows irrespective of gestational day. Maternal and fetal concentrations of melatonin were increased (P < 0.05) in MEL compared with CON heifers. The percent of placentome capillary area per mm2 was decreased (P = 0.019) in MEL compared with CON heifers, while cotyledonary ANGPT1 mRNA tended to increase (P = 0.095) in MEL compared with CON heifers. At weaning, body weight of male offspring and their scrotal circumference were increased (P < 0.05) in calves born to MEL compared with CON dams, while seminiferous tubule diameter and area were not different (P > 0.40) between treatments. In summary, melatonin supplementation increased uterine artery blood flow in mid to late gestating cattle, but this was not accompanied by an increase in fetal weight. Alterations in postnatal development of bulls, including increased body weight and scrotal circumference, warrants future investigations related to attainment of puberty and subsequent fertility of offspring born to melatonin supplemented dams.