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Adequate maternal nutrition is key for proper fetal development and epigenetic programming. One-carbon metabolites (OCM), including vitamin B12, folate, choline, and methionine, play a role in epigenetic mechanisms associated with developmental programming. This study investigated the presence of B12 and folate in maternal serum, allantoic fluid (ALF), and amniotic fluid (AMF), as well as how those concentrations in all three fluids correlate to the concentrations of methionine–folate cycle intermediates in heifers receiving either a control (CON) or restricted (RES) diet for the first 50 d of gestation and fetal hepatic gene expression for methionine–folate cycle enzymes. Angus cross heifers (n = 43) were estrus synchronized, bred via artificial insemination with semen from a single sire, and randomly assigned to one of two nutrition treatments (CON = 20, RES = 23). Heifers were ovariohysterectomized on either day 16 (n = 14), 34 (n = 15), or 50 of gestation (n = 14), where samples of maternal serum (n = 42), ALF (n = 29), and AMF (n = 11) were collected and analyzed for concentrations of folate and B12. Concentrations of B12 and folate in ALF were greater (P

Five ruminally and duodenally cannulated red angus steers (n = 5; initial body weight [BW] = 542 kg, SD = 40 kg) were used in a three-period Youden square design consisting of three 21-d periods, three treatments, and five steers (one or two steers per treatment within each period) to evaluate the effect of feeding hempseed cake on ruminal fermentation parameters, organic matter (OM) intake, total tract nutrient digestion, and nitrogen (N) balance in steers fed finishing diets. The control (CON) diet contained 75% dry-rolled corn, 20% corn silage, and 5% supplement (DM basis). The dried corn distillers grains plus solubles (DDGS) and hempseed cake (HEMP) diets contained 55% dry-rolled corn, 20% corn silage, 20% dried corn distillers grains plus solubles or hempseed cake, and 5% supplement (DM basis). Total ruminal volatile fatty acid concentration was greater (P0.01) in steers fed the HEMP diet than in steers fed the DDGS or CON diets. Ruminal fluid pH was not influenced (P = 0.93) by treatment. Organic matter intake tended (P = 0.07) to be greater and OM total tract digestibility was less (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS or CON diets. Ruminal true and total tract apparent N digestibility was greater (P0.01) in steers fed the HEMP diet than steers fed the DDGS or CON diets. Duodenal flow of essential, nonessential, and total amino acids was not influenced (P ≥ 0.37) by dietary treatment, but the lack of response was likely because ruminally degradable protein (RDP) supply exceeded the RDP requirement. Steers fed the HEMP diet had greater (P0.01) N retention (g/d) than steers fed the DDGS diet, which was greater (P0.01) than steers fed the CON diet, suggesting that feeding hempseed cake improved utilization of N. Although inclusion of hempseed cake decreased total tract OM digestibility compared with dried corn distillers grains or corn, improvements in N utilization suggest that hempseed cake could be a useful alternative feed ingredient for finishing cattle diets.This experiment evaluated the effects of dietary inclusion of hempseed cake or dried corn distillers grains plus solubles on ruminal fermentation parameters, organic matter (OM) intake, total tract nutrient digestion, and nitrogen (N) balance in steers fed finishing diets. Steers were assigned to one of three dietary treatments (no byproduct [CON], 20% dried corn distillers grains plus solubles [DDGS], or 20% hempseed cake [HEMP]; dry matter basis). Hempseed cake had greater acid detergent fiber concentrations, which resulted in greater acid detergent fiber flow to the small intestine and reduced total tract organic matter digestibility in steers fed the HEMP diet than in steers fed the DDGS or CON diets. Steers fed the HEMP diet had greater ruminal and total tract N digestibility, and greater ruminal ammonia concentrations than steers fed DDGS or CON diets, suggesting that the crude protein in hempseed cake is degraded to a greater extent in the rumen and total tract. Although inclusion of hempseed cake decreased total tract OM digestibility compared with dried corn distillers grains or no byproduct, the observed greater ruminal and total tract N digestibility suggest that it could be a useful alternative feed ingredient for finishing cattle diets.

The objective of this study was to determine the dose of folate and vitamin B12 in beef heifers fed rumen protected methionine and choline required to maintain increased B12 levels and intermediates of the methionine-folate cycle in circulation. Angus heifers (n = 30; BW = 392.6 ± 12.6 kg) were individually fed and assigned to one of five treatments: 0XNEG: Total mixed ration (TMR) and saline injections at day 0 and 7 of the estrous cycle, 0XPOS: TMR, rumen protected methionine (MET) fed at 0.08% of the diet DM, rumen protected choline (CHOL) fed at 60 g/d, and saline injections at day 0 and 7, 0.5X: TMR, MET, CHOL, 5 mg B12, and 80 mg folate at day 0 and 7, 1X: TMR, MET CHOL, 10 mg vitamin B12, and 160 mg folate at day 0 and 7, and 2X: TMR, MET, CHOL, 20 mg B12, and 320 mg folate at day 0 and 7. All heifers were estrus synchronized but not bred, and blood was collected on day 0, 2, 5, 7, 9, 12, and 14 of a synchronized estrous cycle. Heifers were slaughtered on day 14 of the estrous cycle for liver collection. Serum B12 concentrations were greater in the 0.5X, 1X, and 2X, compared with 0XNEG and 0XPOS on all days after treatment initiation (P

A growing number of studies have investigated the viability of feeding hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake (HSC) on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers [19-months old; initial body weight (BW) = 494 ± 10 kg] were fed a corn-based finishing diet (10% forage) containing either 20% HSC (n = 15) or 20% corn distillers grains (Control, n = 16) for 111 days until slaughter. Individual feed intake, feeding behavior and BW were measured throughout the study. Rumen fluid and deep nasopharyngeal swabs (days 0 7, 42, 70 and 98), and vaginal and uterine swabs (at slaughter) were collected, and the microbiota assessed using 16S rRNA gene sequencing. HSC feeding resulted in reduced average daily gain (P = 0.05) without influencing feed intake and feeding behavior (P > 0.05) (reported elsewhere). Sampling time had a significant effect on both ruminal (PERMANOVA: R2 = 0.39; P < 0.001) and nasopharyngeal (R2 = 0.18; P < 0.001) microbial community structure. There was also a significant effect of diet on the ruminal (d7– 98; 0.06 ≤ R2 ≤ 0.12; P < 0.05), nasopharyngeal (d 42; R2= 0.18; P < 0.001), and vaginal (R2 = 0.06; P < 0.01) microbiota. Although microbial richness in the rumen, nasopharynx, vagina, and uterus was not affected (P > 0.05) by HSC feeding, microbial diversity (Shannon diversity) was increased in the rumen (d42-98) but reduced in the uterus of HSC heifers (P < 0.05). The relative abundance of five ruminal genera was enriched, while five vaginal genera were reduced in HSC heifers (P < 0.05). Overall, the results of our longitudinal study suggest that feeding hemp by-products can alter the bovine gut, respiratory and reproductive microbiota.

There is interest in feeding industrial hemp production byproducts to livestock, but little is known about the digestibility and ruminal fermentation parameters associated with this feedstuff. A nutrient balance experiment using crossbred steers (n = 5; initial BW = 542 kg, SD = 40 kg) in a Youden square design was conducted to evaluate the effects of feeding hempseed cake (HEMP) or dried corn distillers grains plus solubles [DDGS; each included at 20% of diet dry matter (DM) in respective treatments] in comparison with a dry-rolled corn-based negative control treatment (CON) on ruminal fermentation parameters, nutrient digestibility, nutrient flow and nitrogen (N) balance. Organic matter (OM) tended (P = 0.07) to increase and OM total tract apparent digestibility decreased (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS and CON diets. Total tract apparent N digestibility was greatest (P < 0.01) in steers fed the HEMP diet, while total tract apparent digestibility in all other nutrients was not influenced (P ≥ 0.13) by treatment. Furthermore, apparent ruminal digestibility of OM was greatest (P < 0.01) in steers fed the HEMP or CON diets, and neutral detergent fiber, acid detergent fiber (ADF), and true ruminal digestibility of N was greatest (P ≤ 0.04) in steers fed the HEMP diet. Ruminal total amino acid degradation and total ruminal VFA concentration was greatest (P < 0.01) in steers fed the HEMP diet. A treatment by hour interaction (P = 0.01) was observed for ruminal ammonia concentration. Nitrogen retention was greatest (P < 0.01) in steers fed the HEMP diet, suggesting that feeding hempseed cake improved utilization of N. These results suggest that although ruminal digestibility of all nutrients is greater in steers fed the HEMP diet, greater ADF concentration in hempseed cake negatively influences total tract apparent OM digestibility when fed to finishing steers.

Hempseed cake, a byproduct of industrial hemp and subsequent hempseed oil extraction processes, contains cannabinoids and fatty acids that could be potentially therapeutic for livestock, but little is known about the extent to which hempseed cake can influence immune response variables of cattle. An endotoxin challenge experiment using crossbred steers (n = 5; initial BW = 542 kg, SD = 40 kg) was conducted to evaluate the effects of hempseed cake treatment (HEMP) and dried corn distillers grains plus solubles treatment (DDGS; each included at 20% of diet DM in respective treatments) in comparison with a dry-rolled corn-based negative control treatment (CON) on plasma glucose, non-esterified fatty acids (NEFA), urea nitrogen (PUN), rectal temperature, twelve cytokine (IFNγ, IL-1α, IL-6, IL-8, IL-10, IL-36RA, IP10, MCP-1, MIP-1α, MIP-1β, TNFα, and VEGF-A), and amino acid concentrations at five timepoints after administration of endotoxin (lipopolysaccharide; LPS). Steers were administered LPS at 0.25 μg/kg BW, and blood was collected via jugular venipuncture before and 1, 2, 4 and 6-hours post-bolus injection. Data were analyzed as repeated measures using the MIXED procedure of SAS, and pre-bolus values was used as a covariate. A treatment by hour interaction (P = 0.04) was observed for PUN, and pre-bolus PUN was greatest (P < 0.01) in steers fed the HEMP. Plasma IL-1α, IL-36RA, and TNF-α were least (P ≤ 0.02), while IL-10 and MIP-1α tended (P ≤ 0.10) to be less in steers fed the HEMP diet. Plasma isoleucine, leucine, tryptophan, and tyrosine concentrations were greatest (P ≤ 0.04) in steers fed the DDGS diet, plasma aspartic acid and glycine concentrations were greatest (P ≤ 0.02) for steers fed the DDGS and CON diets. Overall, these data suggest that hempseed cake has potential to reduce inflammation by influencing cytokine production, but more research is needed to further understand animal growth performance and health implications.

We examined the hypothesis that maternal nutrition and day of gestation would affect the concentrations of AAs and hexoses in bovine utero-placental fluids and maternal serum from days 16 to 50 of gestation. Forty-nine cross-bred Angus heifers were bred via artificial insemination and fed a control diet (CON = 100% of requirements for growth) or a restricted diet (RES = 60% of CON) and ovariohysterectomized on days 16, 34, or 50 of gestation; nonpregnant controls were not bred and ovariohysterectomized on day 16 of the synchronized estrous cycle. The resulting design was a completely randomized design with a 2 × 3 factorial + 1 arrangement of treatments. Maternal serum, histotroph, allantoic fluid, and amniotic fluid were collected at time of ovariohysterectomy. Samples were then analyzed for concentrations of AAs and intermediary metabolites: alanine (Ala), arginine, asparagine (Asn), aspartate (Asp), citrulline, cysteine, glutamine, glutamate (Glu), glycine (Gly), histidine, isoleucine, leucine (Leu), lysine, methionine (Met), ornithine, phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), tryptophan, tyrosine (Tyr), and valine (Val). The concentrations of Gly, Ser, and Thr in maternal serum were greater (P ≤ 0.05) in CON compared with RES. Furthermore, day of gestation affected (P ≤ 0.05) concentrations of Asn, Glu, Phe, Thr, and Tyr in maternal serum. Status of maternal nutrition affected the Asp concentration of histotroph where RES was greater (P = 0.02) than CON. In histotroph, Ala, Leu, Met, and Val concentrations were greater (P ≤ 0.05) on day 50 compared with day 16. Additionally, Glu and Pro concentrations in histotroph were greater (P < 0.01) on days 34 and 50 compared with day 16. A day × treatment interaction was observed for the concentration of Val in allantoic fluid where day 34 CON was greater (P = 0.05) than all other days and nutritional treatments. In addition, the concentration of Gln in amniotic fluid experienced a day × treatment interaction where day 34 RES was greater (P ≤ 0.05) than day 34 CON, which was greater (P ≤ 0.05) than day 50 CON and RES. These data support our hypothesis that day of gestation and maternal nutrition affect the concentrations of various neutral and acidic AA in beef heifer utero-placental fluids and maternal serum from days 16 to 50 of gestation.

As cannabinoid production continues to increase, there is increasing interest in feeding byproducts of industrial hemp production to livestock. An experiment using crossbred heifers (n = 31; initial BW= 494 kg, SE = 10) was conducted to determine the effects of feeding hempseed cake in a corn-based finishing diet (10% forage) formulated to meet or exceed ruminally degradable and metabolizable protein requirements on growth, performance, carcass characteristics, and feeding behavior. Heifers were assigned randomly to one of two treatments: 1.) diet containing 20% dried distillers grains plus solubles (CON, n = 16), or 2.) diet containing 20% hempseed cake (HEMP, n = 15) on a dry-matter basis. Cattle were housed in two pens, had ad-libitum access to feed and water, and individual intakes and feeding behavior were captured using the Insentec BV feeding system across the feeding period (111 d). Final BW was not different (P = 0.28) between CON (696 kg, SE = 12) and HEMP (683 kg, SE = 12) heifers. Dry matter intake was not different between treatments (P = 0.99), while CON cattle had improved ADG and feed efficiency (G:F; P ≤ 0.04) compared to HEMP cattle. Carcass characteristics were not different (P ≥ 0.20) between treatments for all parameters measured. Control and HEMP cattle were not different (P ≥ 0.34) for number of meals, time spent eating, number of visits to the bunk per day, meal size, or eating rate. Feeding hempseed cake reduced ADG and G:F while having no effect on other performance measures, carcass characteristics, or feeding behavior. Overall, these data suggest hempseed cake could be a viable alternative feed source for ruminants depending on availability and cost. Further understanding of hempseed cakes’ nutrient utilization is critical to determining this products viability as a feedstuff for cattle.

We hypothesized that maternal nutrition during the first 50 d of gestation would influence the abundance of hexose transporters, SLC2A1, SLC2A3, and SLC2A5, and cationic amino acid transporters, SLC7A1 and SLC7A2, in heifer uteroplacental tissues. Angus-cross heifers (n = 43) were estrus synchronized, bred via artificial insemination, and assigned at breeding to 1 of 2 dietary intake groups (CON = 100% of requirements to achieve 0.45 kg/d of BW gain or RES = 60% of CON intake) and ovariohysterectomized on day 16, 34, or 50 of gestation (n = 6 to 9/d) in a completely randomized design with a 2 × 3 factorial arrangement of treatments. Uterine cross-sections were collected from the horn ipsilateral to the corpus luteum, fixed in 10% neutral buffered formalin, sectioned at 5 µm, and stained via immunofluorescence for transporters. For each image, areas of fetal membrane (FM; chorioallantois), luminal epithelium (ENDO), superficial glands (SG), deep glands (DG), and myometrium (MYO) were analyzed separately for relative intensity of fluorescence as an indicator of transporter abundance. Analysis of FM was only conducted for days 34 and 50. No transporters in target areas were influenced by a day × treatment interaction (P ≥ 0.06). In ENDO, all transporters were differentially abundant from days 16 to 50 of gestation (P ≤ 0.04), and SLC7A2 was greater (P = 0.05) for RES vs. CON. In SG, SLC7A1 and SLC7A2 were greater (P ≤ 0.04) at day 34 vs. day 16. In DG, SLC2A3 and SLC7A1 were greater (P ≤ 0.05) for CON vs. RES heifers; furthermore, SLC7A1 was greater (P < 0.01) at day 50 vs. days 16 and 34 of gestation. In MYO, SLC7A1 was greater (P < 0.01) for CON vs. RES and was greater (P = 0.02) at days 34 and 50 vs. day 16. There were no differences in FM (P ≥ 0.06). Analysis of all uterine tissues at day 16 determined that SLC2A1, SLC2A3, and SLC7A2 were all differentially abundant across uterine tissue type (P < 0.01), and SLC7A1 was greater (P = 0.02) for CON vs. RES. Analysis of all uteroplacental tissues at days 34 and 50 demonstrated that all transporters differed (P < 0.01) across uteroplacental tissues, and SLC7A1 was greater (P < 0.01) for CON vs. RES. These data are interpreted to imply that transporters are differentially affected by day of gestation, and that hexose and cationic amino acid transporters are differentially abundant across utero-placental tissue types, and that SLC7A1 is responsive to maternal nutritional treatment.

The focus of this review is maternal nutrition during the periconceptual period and offspring developmental outcomes in beef cattle, with an emphasis on the first 50 d of gestation, which represents the embryonic period. Animal agriculture in general, and specifically the beef cattle industry, currently faces immense challenges. The world needs to significantly increase its output of animal food products by 2050 and beyond to meet the food security and agricultural sustainability needs of the rapidly growing human population. Consequently, efficient and sustainable approaches to livestock production are essential. Maternal nutritional status is a major factor that leads to developmental programming of offspring outcomes. Developmental programming refers to the influence of pre-and postnatal factors, such as inappropriate maternal nutrition, that affect growth and development and result in long-term consequences for health and productivity of the offspring. In this review, we discuss recent studies in which we and others have addressed the questions, “Is development programmed periconceptually?” and, if so, “Does it matter practically to the offspring in production settings?” The reviewed studies have demonstrated that the periconceptual period is important not only for pregnancy establishment but also may be a critical period during which fetal, placental, and potentially postnatal development and function are programmed. The evidence for fetal and placental programming during the periconceptual period is strong and implies that research efforts to mitigate the negative and foster the positive benefits of developmental programming need to include robust investigative efforts during the periconceptual period to better understand the implications for life-long health and productivity.

We hypothesized that maternal nutrition and day of gestation would influence the abundance of the neutral amino acid transporters SLC1A1, SLC1A5, SLC7A5, SLC38A2, and SLC38A7 in heifer utero-placental tissues. Angus-cross heifers (n = 43) were estrus synchronized and bred via AI. At breeding, heifers were assigned to one of two dietary intake groups (CON = 100% of requirements to achieve 0.45 kg/d gain or restricted heifers (RES) = 60% of CON intake) and ovariohysterectomized on day 16, 34, or 50 of gestation (n = 6 to 9/d). Thus, the experimental design was a completely randomized design with a 2 × 3 factorial arrangement of treatments. Uterine cross sections were taken from the horn ipsilateral to the CL, fixed in 10% NBF, sectioned at 5 µm, and stained for transporters. For each image, the areas of fetal membrane (FM; chorioallantois), endometrium (ENDO), superficial glands (SG), deep glands (DG), and myometrium (MYO) were analyzed separately for relative intensity of fluorescence as an indicator of transporter abundance. Analysis of FM was only conducted on days 34 and 50. In ENDO, SLC7A5 was greater (P < 0.01) in CON compared with RES heifers. In SG, SLC1A1 was greater (P = 0.02) in day 16 RES compared with day 16 CON and days 34 and 50 RES. In DG, SLC1A1 was greater (P = 0.02) on day 16 compared with 50 of gestation. In MYO, SLC1A1 was greater (P = 0.02) in day 50 CON compared with day 16 CON and day 50 RES. Additionally, in MYO SLC38A2 was greater (P = 0.02) in day 16 RES compared with day 16 CON and day 34 RES. In FM, SLC7A5 tended (P = 0.08) to be greater in CON vs RES. Analysis of all uterine tissues on day 16 determined that expression of SLC1A1, SLC1A5, SL38A2, and SL38A7 differed across uterine tissue type (P < 0.01); however, only SLC7A5 tended (P = 0.10) to differ and be greater in CON compared with RES heifers. Analysis of all utero-placental tissues on days 34 and 50 determined that SLC1A1, SLC7A5, SLC38A2, and SLC38A7 were greater (P ≤ 0.03) in CON compared with RES heifers. Furthermore, abundance of all transporters investigated on days 34 and 50 differed across utero-placental tissue types (P < 0.01). These data support our hypothesis that maternal nutrition and day of gestation influence the abundance of neutral amino acid transporters in utero-placental tissues from days 16 to 50 of gestation. Additionally, these data combined with previously published works help further elucidate nutrient supply and demands of the maternal and fetal system during early gestation in beef heifers.

We hypothesize that syncytin-Rum1, bovine endogenous retrovirus-K1 (BERV-K1), pregnancy-specific protein-B (PSP-B), and interferon-τ (IFN-τ) will be influenced by maternal nutrient restriction and be differentially expressed during key stages (day 16, 34, and 50) of the establishment of gestation when fed to meet industry standards. Commercial crossbred heifers (n = 49) were maintained on a total mixed ration and supplemented with dried distillers grains with solubles. All heifers were subjected to 5-d CO-Synch + CIDR estrus synchronization protocol. Non-pregnant, non-bred control (NP-NB) heifers (n = 6) were ovariohysterectomized on day 16, and the remaining heifers were AI to a single Angus sire (day of breeding = day 0). On the day of breeding, heifers were randomly assigned to dietary treatments. One half were assigned to control treatment (CON) targeted to gain 0.45 kg/d, and the remaining half were assigned to restricted treatment (RES), which received 60% of control diets. Heifers were subjected to ovariohysterectomy on day 16, 34, or 50 of gestation. Utero-placental tissues were obtained from the uterine horn ipsilateral (P) and contralateral (NP) to the corpus luteum and separated into maternal caruncle (CAR), maternal endometrium, inter-caruncle, (ICAR), and fetal membrane (FM). There were no interactions between stage of gestation and nutritional treatment for syncytin-Rum1 or PSP-B (P > 0.22). Expression of BERV-K1 was influenced by a treatment × stage of gestation interaction (P = 0.03) in NP-CAR. On day 50, heifers fed the CON diet had greater BERV-K1 expression compared with CON heifers on day 16 and 34 and RES heifers at all sampling time points. There was a treatment × stage of gestation interaction (P < 0.01) for IFN-τ in FM tissue. On 16 d, mRNA expression of IFN-τ was greater (P < 0.01) compared with day 34 and 50 for both CON and RES heifers, but RES FM had greater (P < 0.01) IFN-τ expression compared with CON FM. In P-CAR, PSP-B expression increased (P < 0.01) by 18 000-fold on day 50 compared with NP-NB heifers. In P-ICAR, expression of syncytin-Rum1 in P-ICAR was greater (P = 0.01) on day 16 with a 14.14-fold increase compared with relative expression on day 34 and 50; whereas, PSP-B was increased (P < 0.01) on day 34 and 50 compared with day 16. In conclusion, 40% nutrient restriction had limited influence on mRNA of ERVs, PSP-B, and IFN-τ but stage of gestation differences reinforced the importance of these genes during the establishment of pregnancy.

We hypothesized that both day of gestation and maternal nutrition would alter the relative mRNA expression of neutral and acid AA transporters , , , , and . Crossbred Angus heifers ( = 49) were synchronized, bred via AI, assigned to nutritional treatment (100% of NRC requirements for 0.45 kg/d gain [control heifers {CON}] and 60% of CON [restricted heifers {RES}]), and ovariohysterectomized on d 16, 34, or 50 of gestation ( = 6 to 9/d). Nonbred, nonpregnant (NB-NP) controls were ovariohysterectomized on d 16 of the estrous cycle ( = 6) after synchronization. The resulting arrangement was a 2 × 3 factorial + 1 (CON vs. RES × d 16, 34, or 50 + NB-NP controls). Tissues collected included caruncular endometrium (CAR), intercaruncular endometrium (ICAR), fetal membranes (FM; chorioallantois; d 16 and 34), cotyledonary placenta (COT; d 50 only), intercotyledonary placenta (ICOT; d 50 only), and amnion (AMN; d 50 only]). Relative expression of , , , , and was determined for each tissue using NB-NP CAR and NB-NP ICAR tissues for the baseline; for FM, endometrium from NB-NP controls served as the baseline. In CAR, no day × treatment interaction was observed ( > 0.05). However, day of gestation affected relative expression of , where expression on d 16 was greater ( 0.05) in FM; however, expression on d 34 was greater ( = 0.02) than on d 50, with that on d 16 being intermediate. Day of gestation also affected expression of , where expression on d 34 and 50 was greater ( < 0.01) than that on d 16. These data support our hypothesis in that both day of gestation and maternal nutrition affected the relative mRNA expression of AA transporter in ICAR, whereas day of gestation has a greater effect on the relative mRNA expression of other neutral and acidic AA transporters in the various tissues studied.

The objectives of this study were to investigate the effects of feeding 60% dried corn distillers grains plus solubles (DDGS) or the equivalent sulfur as CaSO4 on DNA structure and integrity in frozen/extended bull semen. Thirty-six half-sibling Angus bulls (256 ± 8 d; initial BW = 320 ± 2 kg) were assigned to one of three treatments: 1) corn-based diet containing 60% concentrate (CON; S = 0.18%; n = 12); 2) diet containing 60% DDGS as a replacement for corn (60DDGS; S = 0.55% DM; n = 12); 3) CON diet + equivalent sulfur of 60DDGS added as CaSO4 (SULF; S = 0.54%; n = 12). Bulls were individually fed in Calan gates for 112 days and targeted to gain 1.6 kg/d. Semen was collected via electroejaculation at d 112. Semen samples were extended and frozen. The Guava easyCyte 8HT Flow Cytometer was used to analyze acrosome/cell membrane integrity, mitochondrial energy potential, oxidation status, DNA integrity and the zinc signature assay. Data were analyzed using PROC MIXED in SAS for effects of treatment. For depolarized mitochondria, 60DDGS tended (P = 0.07) to be greater compared with SULF and CON. This suggests that bulls in the 60DDGS treatment may have sperm with lower mitochondrial energy potential compared with SULF and CON bulls. Additionally, for the zinc signature assay, no differences (P ≥ 0.11) were observed for signatures 2 through 4. However, for signature 1, 60DDGS and SULF had decreased (P = 0.03) signature 1 compared with CON suggesting that sperm from bulls in the SULF and 60DDGS treatments may be in advanced stages of sperm capacitation in comparison to CON, potentially limiting the sperm lifespan and ability to bind the sperm oviductal reservoir.

Thirty-six half-sibling yearling Angus bulls [256 ± 8 d; initial BW = 320 ± 2 kg] were assigned one of three diets: 1) 60% concentrate as corn (CON; n = 12); 2) 60% DDGS (60DDGS; n = 12); 3) CON diet + equivalent sulfur of 60DDGS as CaSO4 (SULF; n = 12) to evaluate effects of feeding 60% DDGS or sulfur as CaSO4 on trace mineral (TM) concentrations in serum and seminal plasma. Bulls were fed in Calan gates for 112 days and targeted to gain 1.6 kg/d. Data were analyzed as repeated measures using PROC MIXED in SAS. In serum, treatment × day interactions were observed (P ≤ 0.03) for Cu, Se, and Mo. For Cu, no differences (P > 0.15) were observed at d 0 or 56, but at d 112, 60DDGS was reduced (P < 0.01) compared with SULF and CON. At d 0, no differences (P > 0.09) were observed for Se; however, at d 56 and 112, 60DDGS was greater (P < 0.01) than CON and SULF. For Mo, at d 0, 60DDGS was greater (P = 0.03) than CON, whereas SULF was intermediate, but at d 56 and 112, CON was greater (P < 0.01) than SULF and 60DDGS. In seminal plasma, treatment × day interactions were observed (P ≤ 0.02) for Cu and Mo. For Cu, no differences (P ≥ 0.09) were observed at d 0 or 56, but at d 112, CON and 60DDGS were greater (P < 0.01) compared with SULF. For Mo, at d 0, 60DDGS was greater (P = 0.03) than SULF, whereas CON was intermediate, but on d 56 and 112, CON was greater (P < 0.01) than 60DDGS and SULF. Differences observed for TM may have influenced enzyme activity and semen kinematics which were previously reported.

We hypothesized that a standing flank ovariohysterectomy procedure could be developed in beef heifers that would provide high quality tissues for addressing critical questions during early pregnancy, while concomitantly keeping livestock stewardship a high priority. To test the hypothesis, we: 1) developed a standing flank ovariohysterectomy procedure for use in beef heifers, and 2) implemented this procedure in a cohort of heifers up to d 50 of pregnancy for tissue collections, documentation of post-surgical recovery, and assessment of feedlot finishing performance. Ovariectomy and cesarean section protocols are well established in research and veterinary medicine and were used as starting points for procedural development. Crossbred Angus heifers ( = 46; ∼ 15 mo of age; BW = 362.3 ± 34.7 kg) were used to develop this new surgical tissue collection technique. Heifers were subjected to the 5-d CO-Synch + CIDR estrous synchronization protocol so ovariohysterectomy occurred at d 16, 22, 28, 34, 40, and 50 of gestation. Key aspects of the standing flank ovariohysterectomy technique included 1) use of local anesthetic for a standing flank incision, 2) locate the uterine and ovarian arteries via blind palpation and ligate them through the broad ligament via an improved clinch knot, 3) cut the ovaries and uterus free from the broad ligament, 4) ligate the cervix and uterine branch of the vaginal artery, and 5) cut through the cervix and remove the reproductive tract. Surgical times, from skin incision to placement of the last suture, were influenced ( = 0.04) by stage of gestation. In pregnant heifers, time decreased from d 22 (120.0 ± 12.0 min) of gestation to d 40 (79.5 ± 12.0 min) of gestation; then increased at d 50 (90.5 ± 14.7 min) of gestation. Using this procedure, we obtained uterine, placental, and embryo/fetal tissues that had experienced limited hypoxia, little or no trauma, and thus were excellent quality for scientific study. All heifers recovered from surgery quickly and were moved to a finishing period. During the finishing period, ovariohysterectomized heifers had a DMI of 13.8 kg, gained 1.99 ± 0.35 kg/d, and had a G:F of 0.145 over 132-d. The standing flank ovariohysterectomy technique represents a new and viable model to economically obtain high quality tissues for investigating critical biological mechanisms during early pregnancy in beef heifers.

The objective of this experiment was to evaluate effects of administering injectable trace mineral supplements to beef cows at the initiation of estrus synchronization on pregnancy rates to AI. Four hundred seventeen Angus and Red Angus-based beef cows at two locations were stratified by parity, body condition score, and days postpartum, then randomly assigned to one of 2 treatments; 1) untreated controls (CON; n = 208); or 2) received 90 mg Cu, 60 mg Mn, 30 mg Se, and 360 mg Zn as an injectable TM supplement initiation of synchronization (6 ml Multimin 90 s.q.; ITM; n = 209). All cows received a controlled internal drug release insert (CIDR; 1.38g progesterone) and 100 µg gonadotropin-releasing hormone (GnRH) im, followed in 7 d by CIDR removal and 25 mg prostaglandin F2alpha, followed in 60 to 66 hours with AI and 100 µg GnRH i.m. Cows received an Estrotech heat detection patch on their tailhead at CIDR removal, which was assigned an activation status at AI (yes = ≥50% of patch activated; no = < 50%). Pregnancy status was determined via transrectal ultrasound on day 35 to 40 after AI to determine pregnancy rates to AI in response to treatments. No location × treatment interaction was present (P = 0.66), but pregnancy rate was greater (P < 0.01) for Location 1 (76.9%; 70 of 91) than for Location 2 (58.0%; 189 of 326). However, no differences (P = 0.50) in pregnancy rates were observed among CON (123/208; 63.5%) and ITM (127/209; 60.8%). Overall, 56.6% of cows had activated estrus detection patches at AI, and more cows with activated patches became pregnant (169/236; 71.6%) compared with cows having unactivated patches (90/181; 49.7%). In this experiment, ITM administration at the initiation of estrus synchronization had no negative effects on pregnancy rate to AI.

Objective of this study was to evaluate the impact of feeding 60% dried distillers grains plus solubles (DDGS) or the equivalent sulfur from calcium sulfate (CaSO4) to yearling beef bulls on ruminal hydrogen sulfide (H2S). The hypothesis for this study was that bulls consuming elevated concentrations of sulfur in their diet will have an increase in H2S present in the rumen. Twenty-four crossbred beef bulls (10 months of age, BW=319.6 kg) were assigned one of three treatments 1) corn based diet containing 60% concentrate (CON, S=0.2%, n = 8); 2) diet containing 60% DDGS as a replacement for corn (DDGS, S=0.44% DM, n = 8); 3) CON diet+ equivalent sulfur of DDGS in diet added as CaSO4 (SULF, S=0.43%, n = 8). Bulls were individually fed in Calan gates at 2% of BW. Ruminal gas samples were taken via rumen puncture 4 to 6 hours post feeding on d0, 14 and 42. Concentrations of H2S were determined using hydrogen sulfide detector tubes which were connected to a volumetric gas pump (Gastec, Kanawaga, Japan). Data were analyzed as repeated measures using the MIXED procedures of SAS for effects of day, treatment, and a day × treatment interaction. A day × treatment interaction was present for ruminal H2S (P = 0.005). On d0, there was no effect of treatment (P = 0.97). Bulls fed DDGS or SULF had similar H2S concentration on d14 (P = 0.06), while animals fed CON had lower H2S concentration (P = 0.004). On d42, concentrations of H2S was greater in SULF than all other treatments (P£0.006), while DDGS was greater than CON (P£0.05). Elevated H2S in bulls fed the SULF treatment compared with the DDGS treatment may indicate that ruminal availability of sulfur (S) in CaSO4 was greater than that of the combination of sulfuric acid and S-containing amino acids present in DDGS.

Glucose transporter solute carrier family 2 member 14 () is a duplicon of glucose transporter solute carrier family 2 member 3 () with a 95% shared homology to and has not previously been isolated in ruminant uteroplacental tissues. The transporter has been previously isolated in Holstein heifer uterine epithelium but not in ovine epithelium. We hypothesized that and its duplicon would be found in bovine uteroplacental tissues and that maternal nutrition and day of gestation would impact mRNA expression of and . Crossbred Angus heifers ( = 49) were estrus synchronized, bred via AI, and assigned to nutritional treatment (CON = 100% of requirements to gain 0.45 kg/d; RES = 60% of CON) at breeding. Ovariohysterectomy was performed on d 16, 34, or 50 of gestation ( = 6 to 9/d); nonpregnant (NP) controls were not bred and ovariohysterectomized on d 16 of the synchronized estrous cycle ( = 6). The resulting treatment arrangement was a 2 × 3 factorial + 1. Uteroplacental tissues (caruncle, CAR; intercaruncular endometrium, ICAR; and fetal membrane [chorioallantois], FM) were obtained from the pregnant uterine horn immediately after ovariohysterectomy. For NP controls, only CAR and ICAR were obtained. There were no day × treatment interactions for or gene expression in CAR, ICAR, or FM. Expression of in CAR was greater ( = 0.03) on d 50 compared with d 16. In ICAR, was greatest ( = 0.02) on d 50 compared with d 16 and 34 of gestation. In FM, was greater ( = 0.04) on d 16 compared with d 50. Expression of was greater ( = 0.05) in pregnant compared with nonpregnant heifers. Additionally, expression of was greater ( = 0.01) on d 34 and 50 compared with d 16. Expression of in CAR was greater ( = 0.03) on d 50 compared to d 16 and 34. In CAR, tended ( = 0.07) to be greater on d 34 and 50 than on d 16 and was greater ( = 0.02) on d 50 than on d 34. There was no effect of treatment for either or in CAR, ICAR, or FM. These data demonstrate that glucose transporters and are expressed in beef heifer uteroplacental tissues and that they are expressed differentially by day of gestation in bovine uteroplacental tissues.

Endogenous retroviral gene elements have been implicated in development and formation of the feto-maternal interface. A variant of the syncytin endogenous retroviral envelope gene family, , was recently found in ruminants. We hypothesized that mRNA would be differentially expressed in utero-placental tissues and would fluctuate during key time points of early gestation in beef heifers. Commercial Angus crossbred heifers ( = 46; ∼15 mo of age; BW = 362.3 ± 34.7kg) housed in 6-animal pens were fed daily with native grass hay and supplemented with cracked corn to gain 0.3 kg/d. The heifers were estrus synchronized, artificially inseminated, (d of breeding= d 0) and ovariohysterectomized on d 16, 22, 28, 34, 40, and 50 ( = 9, 6, 6, 7, 6, and 5, respectively) of gestation and at d 16 of the estrous cycle for non-bred, non-pregnant controls (NP; = 7). Harvested tissues were separated into maternal caruncle (CAR), intercarunclar endometrium (ICAR), and fetal membranes, (FM; chorioallantois, d 22 and later). All tissues were obtained from the ipsilateral uterine horn to the CL. Statistical analyses were conducted via the GLM procedure of SAS. Maternal CAR expression of was greater ( = 0.003) on d 50 by 81.5-fold compared to NP controls. At d 50 expression of in CAR was 190.3-fold greater than ( < 0.0001) ICAR. Fetal membranes had greater ( < 0.002) expression of from d 22 until d 50 of gestation compared to maternal ICAR (d 16 not analyzed). Expression of in FM was greater ( < 0.004) than in CAR until d 40 of gestation. Therefore, we conclude that is differentially expressed in utero-placental tissues and may be involved in the establishment of pregnancy. The expression of in maternal tissues is completely novel and indicates unique functions of syncytin in ruminant pregnancy.

One hundred and twenty-six yearling angus steers (initial body weight 445.87 ± 7.13 kg) were utilized in a 2 x 2 factorial design to evaluate the impacts of bunk management and modified distillers grains plus solubles (mDGS) inclusion on feedlot performance, hydrogen sulfide concentrations and blood oxygen saturation. Treatments included bunk management strategy either control bunk management (CON; clean bunks at the time of next day’s feeding) or long bunk management (LONG; feed remaining at time of next day’s feeding), and two inclusion rates of mDGS either 25% or 50% (DM Basis). On d 0, 7, 14, 21, 28 and 35 rumen gas samples were collected via rumenocentesis, and arterial blood samples were collected on two steers from each pen. No differences (P ≥ 0.09) were observed for dry matter intake, average daily gain and gain-to-feed ratio for bunk management or mDGS inclusion. Hot carcass weight, ribeye area, marbling score and quality grade were not affected (P ≥ 0.48) by either bunk management or mDGS inclusion. Back fat was greater (P = 0.04) for CON steers compared to LONG (1.30 vs 1.12 ± 0.05cm, respectively), but was not affected (P = 0.59) by mDGS inclusion. Steers on CON had greater (P = 0.03) yield grades compared to LONG (3.21 vs 2.96 ± 0.11, respectively). Bunk management strategy did not impact hydrogen sulfide concentrations or blood oxygen saturation (P = 0.82). Hydrogen sulfide concentrations increased (P < 0.001) with increasing mDGS inclusion. Blood oxygen saturation was influenced by day of sampling (P = 0.01). Blood oxygen saturation was not affected (P = 0.07) by mDGS inclusion. The fact that ruminal hydrogen sulfide concentrations increased while blood oxygen saturation remained similar raises questions about the quantity of hydrogen sulfide and metabolic fate of excess hydrogen sulfide in the blood of ruminant animals.

The objective of this study was to evaluate the impacts of bunk management on animal performance, carcass characteristic, and hydrogen sulfide gas concentrations in beef steers fed modified distillers grains with solubles (MDGS; DM basis). One hundred and thirty-nine steers (initial BW = 240 ± 5.17 kg) were allocated into 16 pens and assigned to one of two treatments: 1) Control-managed bunks: bunks devoid of feed prior to feeding; and 2) Long-managed bunks: bunks with approximately 2.54cm of feed remaining at the time feeding. Treatments were applied during a 28-d adaptation period, during which time, steers were adapted to a common finishing ration containing 25% MDGS (DM basis). Ruminal hydrogen sulfide gas was collected by rumenocentesis from two steers from each of three pens per treatment on d 0, 7, 14, and 28, which correspond to days of diet transition. Animal performance data were collected throughout the study and carcass characteristic data were collected when steers reached market weight. There were no differences (P < 0.13) in BW, ADG, or F:G between treatments during the adaptation period or throughout the entire study. Steers managed with long bunks had greater (P = 0.001) intake during adaptation; however, overall DMI was not different (P = 0.14) between treatments. Hydrogen sulfide gas concentrations were not affected by the day x treatment interaction (P = 0.30) but were affected by day (P = 0.003) with hydrogen sulfide concentrations increasing throughout adaptation. Hydrogen sulfide concentrations tended (P = 0.07) to be greater in steers with long-managed bunks vs. control-managed bunks. There were no differences (P > 0.53) in carcass characteristics. In summary, bunk management had no effect on performance or carcass characteristics and only tended to impact hydrogen sulfide gas concentrations.