The objective was to determine the effects of maternal nutrient restriction during gestation on serum microRNA (miRNA) abundance in cattle. Primiparous Angus-cross cows (n=22) were fed either control (CON; to gain 1 Kg/week) or nutrient restricted (NR; 0.55% NEm) diets based on National Research Council requirements. On day 30 of gestation, cows were blocked by body condition and randomly assigned to one of three diets: CON (n=8) days 30-190; NR (n=7) days 30-110 followed by CON days 110-190 (NR/C); or CON (n=7) days 30-110 followed by NR days 110-190 (C/NR). At 190 days of gestation, maternal serum was collected for RNA isolation and analyzed using a miRNA microarray of known Bos taurus sequences. Data were normalized using LOWESS and analyzed via ANOVA. At 190 days of gestation, 16 miRNAs exhibited differential abundance (P<0.05) between treatments. Cows that underwent NR, irrespective of when the insult occurred, had downregulated bta-miR-126-3p compared to CON cows. Bta-miR-16b was downregulated and three miRNAs upregulated in NR/C compared to C/NR and CON cows. Additionally, seven miRNAs were downregulated and four miRNAs upregulated in C/NR compared to NR/C and CON cows. Comparison of NR/C and C/NR cows revealed three differentially abundant (P<0.04) miRNAs (bta-miR-2487_L-2R-3_1ss15CT, bta-miR-215, and bta-miR-760-5p). Top KEGG pathway enrichment of target genes included: pathways in cancer, PI3K-Akt signaling, focal adhesion, Ras signaling, proteoglycans in cancer, and MAPK signaling. In summary, maternal nutrient restriction altered serum miRNA abundance profiles irrespective of the time at which the nutritional insult was induced.

Lay Summary 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. 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 interferon gamma (IFN gamma), 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 IFN gamma 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, IFN gamma 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. The feeding of a yeast-based feed products decreased cytokines in the blood and their mRNA expression in white blood cells that act on stimulating the inflammatory response. The feeding of this yeast-based feed ingredient also reduced the amount of harmful bacteria in the feces of the heifers.

The objective of this study was to determine effects of maternal nutrient restriction (NR) during early or mid-gestation on uterine composition and miRNA expression in cotyledons. Primiparous Angus-cross cows (n = 38) were synchronized and inseminated using male sexed semen, blocked by body condition score and body weight (BW), and assigned to treatments. Animals were fed either: control (CON; gain 1 kg/week) or NR (55% maintenance energy and crude protein requirements) based on BW. An initial set of animals were fed either NR (n = 8) or CON (n = 8) from day 30-110 of gestation. A second set of animals were fed CON (n = 8) d 30-190 (CON/ CON); NR (n = 7) day 30-110 followed by CON day 110-190 (NR/CON); or CON (n = 7) day 30-110 followed by NR day 110-190 (CON/NR). Cows were harvested on day 110 or 190 of gestation to collect placental tissues. RNA was isolated from cotyledon samples (3 animals/group) prior to microarray analysis using known Bos taurus microRNA sequences. Relative microRNA abundance was analyzed via ANOVA. Maternal NR increased (P < 0.05) cotyledon weight and total placentome surface area irrespective of gestational day. At day 110 of gestation, 51 microRNAs were reduced while 91 microRNAs observed greater abundance (P < 0.05) in NR verses CON cotyledons. At day 190 of gestation, 40 microRNAs were reduced and 26 microRNAs were increased (P < 0.05) in both NR/CON and CON/NR verses CON cotyledons. Top KEGG pathway analysis included: axon guidance, endocytosis, neuroactive ligand receptor interaction, and MAPK signaling pathway. Early-gestation maternal NR altered microRNA abundance to a greater extent than mid-gestation NR.

Objective: Our objective was to determine the effects of ruminally protected UFA supplementation during late gestation on fatty acid (FA) profiles in colostrum and maternal and offspring serum, and transfer of passive immunity in beef cattle. Materials and Methods: Crossbred Angus cows (n = 58) were blocked by parity and then randomly assigned to supplements for the last 90 d of gestation: control (1.5 kg of corn gluten feed; n = 29) or an isocaloric and isonitrogenous supplement containing 200 g of bypass EFA (RBEFA; Essentiom, Church and Dwight Co., Princeton, NJ; n = 29) 5 d per week. Maternal blood was collected on d 45 of treatment and at parturition. Colostrum samples were collected at parturition. Calf blood was collected at birth and 1 and 5 d of age. Serum and colostrum samples were analyzed for FA and IgG concentrations. Data were analyzed via ANOVA with repeated measures when appropriate. Results and Discussion: Total FA concentrations in cows on RBEFA were increased (P < 0.001) compared with cows on control at d 45 and at parturition. Colostrum IgG and serum concentrations of calves at 1 d of age were increased (P < 0.01) in RBEFA compared with control. Serum of calves from dams supplemented with EFA had increased (P = 0.05) total FA concentrations at birth and 5 d of age. Calf BW up to weaning was increased (P < 0.01) in calves from second- and third-parity RBEFA dams. Implications and Applications: Late-gestation supplementation of EFA increased serum FA concentrations, colostrum IgG, and calf serum IgG and increased calf growth up to weaning.

The objective of this study was to determine how weaning age, days on supplements, and lipid supplementation affected the growth and marbling deposition of steers. Steers from a single sire were early weaned (n = 24) at 150 ± 11 days of age or traditionally weaned (n = 24) at 210 ± 11 days of age. Steers were assigned to control (n = 12/weaning group) or an isocaloric, isonitrogenous rumen by-pass lipid (RBL, n = 12/weaning group) for either 45 (n = 6/treatment) or 90 (n=6/treatment) days then harvested. Steer body weight (BW) was recorded on days −14 and −7, then BW and blood samples were collected on days 0, 22, 45, 66, and 90. The right rib section of each animal was collected for proximate analysis. Longissimus dorsi from RBL steers had increased lipids compared with control steers (3.6 ± 0.2 vs. 2.4 ± 0.2% on a wet basis; p < 0.0001). Steers fed for 90 days had greater (p = 0.02) concentrations of Longissimus dorsi lipid (3.3 ± 0.2%) than those fed for 45 days (2.7 ± 0.2%). There was a weaning age by treatment by days on feed interaction for intramuscular adipocyte diameter (p = 0.02) in which early weaned RBL fed for 90 days steers had an increased adipocyte diameter compared to the early weaned control fed for 90 and early weaned fed for 45 days steers with all other treatment groups as intermediates. Supplementation of RBL increased concentrations of C18:2, C20:4, and total fatty acids on days 45 and 90 (p ≤ 0.05). Data show that RBL supplementation increased the marbling content of the Longissimus dorsi. Furthermore, a longer period of supplementation resulted in increased adipose diameter.

The objective was to determine the effects of immunomodulatory feed ingredient during post-weaning on cortisol concentration and fecal microbial populations of beef heifers. Commercial Angus heifers (n = 72) from two AI sires were blocked (n = 9) by sire and BW, randomly assigned to one of two pens (4 heifers/pen) per block, then assigned to treatments. Heifers were fed twice daily from d 0 to 60 (gain 0.75 kg/day) and top-dressed once daily with either 72g of Celmanax (CEL) or corn germ (CON; corn germ meal) per pen. After 60 days, two heifers per pen (n = 32) were randomly selected for a transportation challenge. Fecal grab samples were collected on d 0 and 69 of treatment, hr -24, 0, 24 of the challenge and 7 d post-challenge. Serum samples were collected at h 0, 4, 8, and 12 of the challenge. Clostridia and E. coli were enumerated from fecal samples using selective media. Isolates (≤ five isolates from each media per sample) were genetically tested to determine if they were C. perfringens or pathogenic E. coli. Fecal samples were enriched for detection of Salmonella. Pen was the experimental unit and data was analyzed by ANOVA or repeated measures analysis. Following treatment, decreased (P ≤ 0.05) populations of total E. coli, Salmonella, and C. perfringens were observed in CEL heifers compared to CON heifers, whereas clostridia and pathogenic E. coli were not different (P > 0.05) between treatments. Transportation stress increased (P ≤ 0.05) populations of clostridia, C. perfringens, total E. coli, and Salmonella, but decreased (P = 0.0252) pathogenic E. coli counts. Cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers throughout the challenge. In summary, supplementation of Celmanax post-weaning altered microbial populations and cortisol concentrations were reduced during transportation in beef heifers.

The objective of this study was to determine the effects of an immunomodulatory feed ingredient during post-weaning on growth and cortisol concentrations of beef heifers. Commercial Angus heifers (n = 72) from 2 AI sires were blocked (n = 9) by BW and randomly assigned to one of 2 pens per block. Each pen (4 heifers/pen) per block was randomly assigned to either one of 2 treatments, Celmanax (CEL) or corn germ (CON). The heifers were fed a commercial total mixed ration (TMR) twice daily from d 0 to 60 to gain 0.75 kg/d. The feed was top-dressed once daily with either 72g of Celmanax (CEL) or corn germ (CON) per pen. Body weight (BW) was collected on d -1, 0, 15, 30, 45, 60, and 61. Blood samples were collected on d 0, 15, 30, 45, and 60. Two heifers per pen (n = 32) were randomly selected for a transportation challenge to evaluate stress response on d 62 or 63 of the study. Sixteen heifers (n = 8 CEL; n = 8 CON) were randomly selected for a corticotropin-releasing hormone/arginine vasopressin (CRH/AVP) challenge and an intravenous glucose tolerance test (IVGTT) on d 64 and 67 of the study. The pen was the experimental unit, and data were analyzed by ANOVA or repeated measures analysis as appropriate. Feed efficiency and BW gain were increased (P = 0.04) in CEL heifers compared to CON heifers. Serum cortisol concentrations were decreased (P < 0.01) in CEL heifers compared to CON heifers on d 30 to 60 post-weaning. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers throughout the transportation challenge. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers during the CRH/AVP challenge from 60 to 150 min post-infusion. Treatment did not influence (P = 0.29) plasma insulin or glucose (P = 0.63) concentrations during the IVGTT. In summary, supplementation of Celmanax post-weaning increased BW gain and reduced cortisol concentrations in challenged beef heifers. (C) 2020 Elsevier Inc. All rights reserved.

The objective of this study was to determine the effects of an immunomodulatory feed ingredient during post-weaning on growth and cortisol levels of beef heifers. Commercial Angus heifers (n = 72) from two AI sires were blocked (n = 9) by sire and BW and then randomly assigned to one of two pens per block. Each pen (4 heifers/pen) per block was assigned to one of the treatments. Heifers were fed a commercial TMR twice daily from d 0 to 60 to gain 0.75 kg/day. The feed was top-dressed once a day with either 72g of Celmanax (CEL) or 72g of corn germ (CON) per pen. Body weight was collected on d -1, 0, 15, 30, 45, 60 and 61. Blood samples were collected on d 0, 15, 30, 45 and 60. Sixteen heifers (n = 8 CEL; n = 8 CON) were randomly selected for a corticotropin releasing hormone/ arginine vasopressin (CRH/AVP) challenge after the 60 d period. Two heifers per pen (n = 32) were randomly selected for a transportation challenge to evaluate stress response on d 61 or 62 of the study. Pen was the experimental unit and data was analyzed by ANOVA or repeated measures analysis as appropriate. Feed efficiency and BW gain was increased (P = 0.04) in CEL heifers compared to CON heifers. Serum cortisol concentrations were decreased (P < 0.01) in CEL heifers compared to CON heifers on d 30 to 60 post-weaning. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers during the CRH/AVP challenge from 60 to 150 minutes post infusion. Serum cortisol concentrations were decreased (P < 0.05) in CEL heifers compared to CON heifers throughout the transportation challenge. In summary, supplementation of Celmanax post-weaning increased BW gain and reduced cortisol concentrations in beef heifers.

The link between circulating glucocorticoids and leptin in beef calves has not been explored but has been noted in several studies. The aim of this study is to determine the effects of exogenous glucocorticoids given at birth and 1 day of age on serum leptin concentrations in beef calves. Ruminant animals secrete leptin, which is thought to be important for the programming of the hypothalamic appetite centers. Angus crossbred cows (n=31) bred via natural service were utilized for this experiment. At parturition (day 0), calf BW was recorded and each calf was infused intravenously with either a hydrocortisol sodium succinate solution (HC, 8 males and 8 females) at a dosage of 3.5 μg/kg of BW or a similar volume of saline solution (CONT, 7 males and 8 females). Each calf was given a second infusion of its respective treatment 24 h postpartum at 1.5 μg/kg of BW for HC treatment. Calf treatment was blocked by sex, dam body condition score (BCS), and dam age. Blood samples were taken via jugular venipuncture before infusion, daily from days 0 to 5, then every other day up to day 17. Serum leptin and cortisol concentrations were analyzed via radioimmunoassay. Dam age, dam BCS, calf BW, and serum leptin and cortisol concentrations were analyzed using MIXED procedure of SAS. Dam age was not different (P=0.81) among HC and CONT calves (4.9±0.5 and 4.7±0.5, respectively). Dam BCS was not different between treatments (5.7±0.2 and 5.6±0.2 HC and CONT, respectively; P=0.66). There was no difference in calf birth BW between treatments (P=0.87) and averaged 38.3±1.4 kg. Cortisol concentrations were not different between both treatments (P=0.23) from birth to day 4 of age. Calves that received the HC treatment showed significantly reduced (P=0.03) leptin concentrations on days 1 to 13. Calf BW from 60 to 150 days of age was not different between CONT and HC treated calves (P=0.65). These data indicate that exogenous glucocorticoids can be used to suppress neonatal leptin levels in calves. This could lead to changes in voluntary feed intake of treated calves.

This study's objective was to determine if nutrient restriction during late gestation affected beef heifer feed intake, body weight (BW) gain and endocrine regulation during a 10-week feeding trial. During the last 100 days of gestation, control (CON) dams were fed to increase body condition score (BCS). Whereas, nutrient-restricted dams (NR) and NR dams protein supplemented 3 days/week (NRS) were fed to decrease BCS by 1.2. After parturition, all cow-calf pairs were moved to a common pasture and fed in excess of requirements until weaning. At 15 months of age, heifers were randomly sorted into two pens and adjusted to a commercial total mixed ration over a 2-week period. Blood samples and BW were taken at the initiation of feeding and on a biweekly basis for the duration of the feeding trial. Feed intake was monitored for 10 weeks using a GrowSafe System. After 10 weeks, an intravenous glucose tolerance test (IVGTT) was performed on 21 randomly subsampled heifers. During the feeding trial, NR heifers consumed more feed than CON and NRS heifers. Heifers from NR dams tended to increase BW compared to NRS and CON heifers when adjusted for initial BW. Heifers from NR and NRS dams had a greater increase in BCS compared to heifers from CON dams. Plasma glucose and insulin concentrations during the feeding trial increased in NR heifers compared to the other groups beginning at 2 and 4 weeks respectively. Plasma leptin concentrations were increased in the NR and NRS heifers compared to the CON heifers beginning at week 4 of feeding. During the IVGTT at the conclusion of the feeding challenge, plasma glucose and insulin were increased in NR heifers compared to other treatment groups. These results show that nutrient restriction during late gestation alters appetite and endocrine regulation in heifer offspring.

The aim of this study is to determine the effects of early and mid-gestation nutrient restriction on maternal metabolites and foetal growth. Primiparous Angus cows were synchronized and inseminated with semen from one sire. Dietary treatments were: control to gain 1 kg/week (CON) or 0.55% maintenance energy and CP requirements (nutrient restricted; NR). A subset of dams was fed NR (n=8) or CON (n=8) from days 30 to 110 of gestation. Another group was fed CON (n=8), days 30 to 190; NR (n=7), days 30 to 110 followed by CON days 110 to 190; or CON, (n=7) days 30 to 110 followed by NR days 110 to 190. Cows were harvested at days 110 or 190 of gestation, when foetal measurements and samples were collected. Cows that were NR during days 30 to 110 or 110 to 190 of gestation lost significant BW and body condition score (P<0.001), this was associated with reduced plasma glucose during NR (P<0.002). Foetal weights, empty foetal weights, abdominal and thoracic circumferences were all reduced (P<0.03) in day 110 NR animals. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.01) in NR day 110 female foetuses compared with CON foetus. Maternal serum triglycerides at day 110 of gestation were decreased (P<0.05) in NR dams, whereas foetal serum triglycerides were increased (P<0.05) in response to maternal NR. Foetal weights tended to be reduced (P=0.08) in NR/CON and CON/NR v. CON/CON cattle at day 190 of gestation. Empty foetal weights, abdominal and thoracic circumferences were reduced (P⩽0.03) in NR/CON and CON/NR v. CON/CON cattle. Brain weight as a percentage of empty foetal weight was increased (P<0.001) in NR/CON and CON/NR v. CON/CON cattle. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.003) in NR/CON and CON/NR v. CON/CON cattle. Maternal serum triglycerides at day 190 of gestation were decreased (P<0.05) in association with maternal NR. Foetal serum triglycerides at day 190 of gestation were increased (P<0.05) in response to maternal NR during early gestation but decreased by NR in mid gestation compared with CON foetuses. The data show that maternal nutrient restriction during early or mid-gestation cause's asymmetrical foetal growth restriction, regardless if the restriction is preceded or followed by a period of non-restriction.

The objective of this study was to determine if supplementation frequency of rumen-protected fat (RPF) influences circulating serum concentrations of fatty acids (FA), NEFA, and urea nitrogen in beef heifers and lactating cows. In Exp. 1, 12 early gestation beef heifers were supplemented 0.5 kg of corn gluten feed (CGF) daily during a 2-wk adaptation period. During the last 3 d of adaptation, blood samples were collected immediately before supplementation and then 8 and 16 h postsupplementation daily. Each heifer was then randomly assigned to 1 of 3 supplementation frequency treatments of RPF (3, 5, or 7 d/wk) for 3 wk in a 3 × 3 Latin square design with 3 periods (4 heifers per treatment per period), with each treatment receiving the same amount of RPF and CGF per wk (1.0 and 2.7 kg as fed, respectively). Blood samples were collected during the final 3 d of each supplementation period as described in the adaptation period. In Exp. 2, 18 Angus crossbred cows in early lactation were supplemented with 4.54 kg (as fed) of CGF weekly either at 3, 5, or 7 d/wk during a 2-wk adaptation period. Blood samples were collected during the last 3 d of adaptation as in Exp. 1. For the subsequent 3 wk, RPF (530, 318, and 227 g/d when supplemented) was added to the CGF supplement so that each supplementation frequency received 1.59 kg as fed/wk of RPF. Blood samples were collected during the last 3 d of supplementation as in Exp. 1. Serum FA profiles on a random subsample of 9 heifers in Exp. 1 and all animals in Exp. 2 were determined via gas chromatograph (GC), and values were analyzed using the MIXED procedure of SAS. In Exp. 1, there were no differences ( ≥ 0.53) in serum FA profile across supplementation frequencies. There was a decrease in serum 18:2, 18:1 -9 and total FA during the sampling time (time effect, < 0.02). In Exp. 2, there was treatment × time effect ( ≤ 0.001) for both 18:2 and total FA measured. The 7 d/wk frequency had a greater concentration of C18:2 and total FA at 8 h of the sampling period when compared to the other 2 frequencies. These results demonstrate that supplementation of RPF at 3, 5 or 7 d/wk resulted in no changes in serum FA profiles in growing heifers. In early lactating beef cows, there were minor time point changes in serum FA due to supplementation frequency; however, the vast majority of time points were not different, indicating no substantial changes in serum FA profiles.

Ruminant animals exhibit a neonatal surge in leptin important for the programming of the hypothalamic center responsible for appetite regulation. Postnatal leptin concentrations have been shown to be influenced by maternal diet and elevated circulating cortisol. It has not yet been established whether postnatal leptin concentrations can be manipulated by exogenous glucocorticoids in cattle. The objective of this study was to investigate the effects of exogenous cortisol on the leptin profile of newborn calves. Angus crossbred cows (n = 31) were blocked by parity, BCS, and age and bred via natural service. Upon parturition (d 0), calf BW was recorded and each calf was infused with either a hydrocortisol sodium succinate solution (HC) at a dosage of 3.5 μg/kg of BW or a similar volume of saline solution (CONT). Each calf was given an additional infusion of its treatment 24 hours post partum at 1.5 μg/kg of BW. Calf treatment was blocked by sex, dam BCS, and dam age. The CONT group consisted of 8 females and 7 males, while the HC group consisted of 8 males and 8 females. Blood samples were taken via jugular venipuncture before each infusion, daily from d 0-5, then every other day up to d 17. Serum samples were stored at -20°C until hormone analysis. Serum leptin and cortisol levels were analyzed via previously validated radioimmunoassay. Dam age, dam BCS, calf birth BW, and serum leptin and cortisol concentrations were analyzed using the MIXED procedure of SAS. Age was similar (P = 0.81) among dams of HC and CONT calves (4.9 ± 0.5 and 4.7 ± 0.5, respectively). Dam BCS was similar between groups (5.7 ± 0.2 and 5.6 ± 0.2 units HC and CONT, respectively; P = 0.66). There was no significant difference in calf birth BW between treatments (P = 0.87), with HC calves weighing 38.5 ± 1.4 kg and CONT calves weighing 38 ± 1.4 kg. There was a tendency (P = 0.09) for HC calves to display reduced cortisol concentrations on d 1 and 2. Calves that received the HC treatment showed significantly reduced (P = 0.03) leptin concentrations on d 1-13. These data indicate that exogenous cortisol can be used to suppress neonatal leptin levels in cattle. This could be utilized as a management tool to increase voluntary intake of calves and impact overall production efficiency.

It has previously been shown that late gestation nutrient restriction results in altered postnatal endocrine regulation and growth in newborn calves. The objective of this study was to determine if nutrient restriction during late gestation affected heifer offspring's DMI, BW gain, and endocrine regulation during a 10 wk feeding trial. During the last 100 d of gestation, control (CON, n = 11) dams were fed to increase BCS by 0.6 ± 0.1. Whereas, nutrient restricted dams (NR, n = 10) and NR dams offered protein supplement three d/wk (NRS, n = 13) were fed to decrease BCS by 1.2 ± 0.2. After parturition, all cow-calf pairs were moved to a common pasture and fed at or in excess of requirements until weaning. After weaning, all heifers were maintained as a single group. At 15 mo of age, heifers were randomly sorted into 2 pens and adjusted to a pelleted TMR over a 2 wk period. Blood samples and BW were taken at initiation of feeding and on a biweekly basis for the duration of the feeding trail. Feed intake was monitored for 10 wk using a GrowSafe System. After 10 wk, an intravenous glucose tolerance test (IVGTT; dose: 0.3g dextrose/kg BW) was performed on 21 randomly subsampled heifers. The NR heifers consumed more feed (P = 0.01) than CON and NRS (1328 ± 49, 1110 ± 45 and 1197 ± 41 kg, respectively). Heifers from NR dams tended (P = 0.07) to increase BW compared to NRS and CON heifers when adjusted for initial BW (26 ± 2, 23 ± 2 and 20 ± 2%, respectively). Heifers from NR and NRS dams had a greater increase (P < 0.01) in BCS compared to heifers from CON dams (1.4 ± 0.2, 1.2 ± 0.1, and 0.7 ± 0.1, respectively). Plasma glucose and insulin concentrations during the feeding trial increased (P < 0.03 and P < 0.0001, respectively) in NR heifers compared to the other groups beginning at 2 and 4 wks, respectively. Plasma leptin concentrations were increased (P = 0.045) in the NR and NRS heifers compared to the CON heifers beginning at 4 wks of feeding. During the IVGTT at the conclusion of the feeding challenge, plasma glucose and insulin were increased (P = 0.02 and P < 0.001) in NR heifers compared to other treatment groups. These results show that nutrient restriction during late gestation alters appetite and endocrine regulation in heifer offspring.

The objective of this study was to determine if supplementation with ruminal protected unsaturated fatty acids (FA) increased colostrum and serum concentrations of IgG of calves and subsequent calf growth. Commercial Angus and Angus crossbred heifers and young cows all bred to a single Angus sire were blocked by breed and parity and randomly assigned to either control (1.5 kg of corn gluten feed, CON n = 29) or an isocaloric isonitrogenous supplement containing 200 mg of ESSENTIOM (Arm & Hammer Animal Nutrition, Princeton, NJ; EFA, n = 29) for the last 90 d of gestation. All supplements were individually fed 5 d/wk. All cows had ad libitum access to the same pastures throughout the study. At parturition a colostrum sample was collected from the dam and a blood sample was collected from calves at 24 h of age. Calf BW was collected every month and adjusted back to every 30 d of age. Serum and colostrum IgG content were determined by ELISA. All data were analyzed using PROC MIXED procedure of SAS either as repeated measures or ANOVA depending on parameters. Dam BW and BCS during late gestation were similar (P > 0.14) between treatments. Colostrum concentrations of IgG were increased (P < 0.01) in EFA cows compared with CON cows (166 ± 13 vs. 102 ± 18 mg/ml, respectively). Calves from EFA dams had a tendency for a reduced (P = 0.08) birth weight compared with calves from CON dams (30.9 ± 0.6 vs. 32.5.6 ± 0.6 kg, respectively). Serum from calves at 24 h of age whose dams were supplemented with EFA had increased (P ≤ 0.01) concentrations of IgG compared with calves whose dams were supplemented CON (11.4 ± 0.7 vs. 7.6 ± 0.7 mg/ml, respectively). Calf growth had a treatment X parity X day interaction (P < 0.01). Calves from EFA dams that had their second or third calves had increased BW (P < 0.05) at 90 to 210 d of age and at 210 d of age respectively compared with calves from CON dams. The results of this study indicate that supplementation of rumen protected unsaturated FA in late gestation beef cows increased colostrum and calf serum IgG and increased calf BW in cows with their second and third calves.

A study was conducted to evaluate late gestation maternal nutrient restriction (NR) with or without protein supplementation on endocrine regulation in newborn beef calves. This study used multiparous cows (4 and 5 years of age, n = 57) randomly assigned to one of three treatments for the last 100 days of gestation. The control (Con; n = 19) cows were fed to increase body condition score, whereas the NR (n = 19) and NR with protein supplement (NRS, n = 19) cows were fed to lose 1.2 ± 0.2 body condition score units during the last 100 days of gestation. Control cows were allowed ad libitum access to tall fescue/crabgrass paddock and, when grazing became insufficient, ad libitum hay was provided along with 1.3 kg of corn gluten feed 5 days/wk. Tall fescue paddocks were strip grazed to limit forage availability for NR and NRS. The NRS-treated dams were individually penned and fed 0.45 kg of soybean meal 3 days/wk. As forage became limited, the nutrient-restricted paddocks received limited fescue hay. After parturition cow/calf pairs were moved to a common pasture and received ad libitum silage and high-concentrate feed. Maternal NR regardless of supplementation reduced cow plasma glucose and insulin concentrations during late gestation (P < 0.0001 and P = 0.0051, respectively). Calves from NR dams weighed less at birth than Con calves (P = 0.04), whereas NRS calves were intermediate (33.4 ± 1.2, 35.0 ± 1.3, and 37.2 ± 1.3 kg NR, NRS, and Con, respectively). Plasma glucose concentrations of unsuckled calves at birth were reduced (P = 0.037) in NR and NRS calves compared with Con (67.7 ± 6.5 and 60.1 ± 6.9 vs. 83.7 ± 6.1 mg/dL, respectively). At birth, Con and NRS calves had increased (P = 0.0037) plasma leptin concentrations compared with NR calves, whereas calf plasma cortisol concentrations were greater for the nutrient-restricted groups than the Con group (treatment × day P = 0.0135). Plasma IgG concentrations from calves at 5 days of age were similar (P = 0.701) between maternal late gestation treatments. This research reports that late gestation NR reduces postnatal calf birth weight, plasma glucose and leads to reduced plasma leptin. Maternal protein supplementation appears to partially alleviate the effects of late gestation NR on reducing plasma leptin, birth weight, and growth rate from Day 30 of age to weaning.

Studies have shown that daily supplementation of rumen protected fats (RPF) is optimal for lactating dairy cows; however, the optimal frequency of supplementation for growing beef animals in unknown. The study's purpose was to determine if supplementation frequency of RPF (Megalac-R) influences BW, BCS, and circulating serum fatty acids (FA) in growing heifers. Twelve early gestation beef heifers (∼60 d of gestation) were supplemented 0.5 kg corn gluten feed daily with access to grazing and hay during a 3-wk adaptation period (AD). During the last 3 d of the adaptation period, blood samples were collected immediately before supplementation, then 8 and 16 h post-supplementation. Subsequently, each heifer was randomly assigned to one of 3 supplementation frequency treatments of RPF for 3 wk in a Latin square design with 3 periods: 3 d/wk (3D), 5 d/wk (5D), or 7 d/wk (7D), with each treatment receiving the same amount of RPF and corn gluten feed per wk. Blood samples were collected during the final 3 d of the supplementation period as in the adaptation period. Serum FA profiles were analyzed on a random subsample of 8 heifers. Heifer BW and BCS changes, along with serum FA profiles, were analyzed using the MIXED procedure of SAS. Heifer BW and BCS changes during the 3 wk period were similar (P > 0.39) between treatments (9, 13, and 10 kg SEM 3 kg; 0, 0, and −0.1 BCS units SEM 0.1; 3D, 5D and 7D respectively). Serum concentrations of 18:2 were increased during supplementation compared to the adaptation period (trt*day*time effect P = 0.04). However, there was no difference between supplementation frequencies within a day*time period. Total serum FA concentrations had a trt*day*time interaction (P = 0.01). Heifers supplemented with RPF had increased serum FA compared to when non-supplemented. There were also decreases in serum FA between the supplementation frequencies over the course of the 3-d sampling period. These results demonstrate that supplementation of RPF during early gestation improves serum FA profiles of beef heifers, specifically increasing concentrations of both 18:2 and total serum FA. However, these improvements do not appear to be dependent on the frequency of RPF supplementation.

The objective of this study was to determine if supplementation with ruminal protected unsaturated fatty acids (FA) increased unsaturated FA in both maternal serum and colostrum during late gestation and in serum from their newborn beef calves. Commercial Angus and Angus crossbred heifers and young cows all bred to a single Angus sire were blocked by breed and parity and randomly assigned to either control (1.5 kg of corn gluten feed, CON n = 29) or an isocaloric isonitrogenous supplement containing 200 mg of ESSENTIOM (EFA, n = 29) for the last 90 d of gestation. All supplements were individually fed 5 d/wk. All cows had ad libitum access to the same pastures throughout the study. Maternal blood samples were collected at 90 and 45 d before expected parturition. At parturition, blood and colostrum samples were obtained from each cow. Blood samples was collected from calves at parturition and then at 5 d of age. Serum and colostrum FA content were determined. All data were analyzed using PROC MIXED procedure of SAS either as repeated measures or ANOVA depending on parameters. Maternal serum concentrations of C16:0, C18:0 C18:1c9, C18:2, C20:4, and total FA were similar in all cows at start of supplementation but increased (treatment × day interaction P < 0.01) in the EFA cows at 45 d before and at parturition compared with CON cows. Colostrum DM was increased (P = 0.01) in EFA cows compared with CON cows (30.4 vs. 25.4%, 1.30 SEM). Colostrum concentrations on a DM basis of C18:2, total FA, and total unsaturated FA were increased (P < 0.05) in EFA cows compared with CON cows. Serum from calves at birth whose dams were supplemented with EFA had increased (P ≤ 0.01) concentrations of C16:0, C18:0, C18:1 t9, C18:2, C20:4 and total FA compared with calves whose dams were supplemented CON. At 5 d of age calves from EFA supplemented dams had increased (P ≤ 0.05) serum concentrations of C18:0, C18:2, C20:4 and total FA compared with serum from calves whose dams were supplemented CON. The results of this study indicate that supplementation of rumen protected unsaturated FA in late gestation beef cows increased circulating and colostrum unsaturated FA, and this resulted in increased unsaturated and total FA at parturition and at 5 d of age in their calves.