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BackgroundAbomasal ulceration is recognized in neonatal and adult cattle, but research regarding treatment is limited. Histamine-2 receptor antagonists (H2 RA), such as famotidine, are used clinically with little evidence-based research about efficacy in adult cattle.Hypothesis and objectivesIntravenous famotidine administered at 0.4 mg/kg will increase the pH of abomasal outflow digesta compared to saline control in adult cattle. The objectives were to assess the effect of famotidine, administered as a single dose and as multiple doses, on abomasal outflow fluid pH in adult cattle. A third objective was to describe the pharmacokinetic parameters of IV famotidine in cattle.AnimalsFour clinically healthy adult Angus-cross steers previously fitted with duodenal cannulae placed orad to the biliary and pancreatic ducts.MethodsRandomized, 2-way cross-over clinical trial. Steers received IV famotidine (0.4 mg/kg) as a single and 3-dose regimen (every 8 hours) versus saline control. Blood for analysis of serum famotidine concentration was collected intermittently for 12 hours, and abomasal outflow fluid pH was measured at intervals for a 24-hour period. After a 34-hour washout period, the opposite treatments were administered and the sampling repeated.ResultsAbomasal outflow fluid pH was higher in steers treated with famotidine for up to 4 hours after a single dose but the effect decreased with subsequent doses. The median (range) elimination half-life was 3.33 (3.21-3.54) hours.Conclusions and clinical importanceFamotidine may be useful for treatment or prevention of abomasal ulceration in adult cattle, but the duration of effect may decrease with time.

To determine factors affecting colostrum yield and quality, data from 148 cow-calf pairs over 6 experiments were combined. In each experiment, single rear quarter colostrum yield was obtained postcalving but pre-suckling. Colostrum IgG was determined by ELISA, and colostrum lactose, triglycerides (as a measure of total fat), and protein were determined by colorimetric analyses. Total IgG and nutrients were calculated as the concentration multiplied by single-quarter yield. Calf birth weight and expelled placental dry weight were also collected post-calving. Mixed linear models (experiment as a random effect) were used to determine the effects of dam age (primiparous: 2 yr, young: 3 to 4 yr, mature: ≥ 5 yr), dam peripartum body condition score (BCS; thin: < 5, moderate: 5 to 5.99, fleshy: ≥ 6), and calf sex on colostrum yield (single-quarter colostrum weight) and quality. Pearson correlation coefficients were also determined for colostrum yield with dam pre-calving body weight (BW), calf birth weight, calf birth weight relative to dam BW, whole placental dry weight, and gestation length. Mature dams had the greatest (P ≤ 0.03) and primiparous dams had the least (P ≤ 0.001) colostrum yield and total lactose. Colostrum from primiparous dams had greater (P = 0.03) IgG concentration than mature and greater (P ≤ 0.001) protein concentration than young and mature. Mature dams had greater (P ≤ 0.02) total IgG, total protein, and total triglycerides compared with both primiparous and young. Colostrum yield was less (P ≤ 0.04) for thin than moderate and fleshy dams. Total IgG was unaffected (P = 0.11) by dam BCS; however, thin dams had greater (P ≤ 0.04) IgG concentration than moderate and fleshy. Lactose concentration and total lactose were less (P ≤ 0.02) in colostrum from thin compared with moderate dams. Protein concentration was greater (P = 0.001) in thin than moderate dams, but thin dams had less (P ≤ 0.02) total protein compared with moderate and fleshy. Dam BCS did not affect (P ≥ 0.59) colostrum triglyceride concentration or total triglycerides. Colostrum yield and quality were not affected (P ≥ 0.22) by calf sex. Pre-calving dam BW was positively correlated with colostrum yield (r = 0.46, P < 0.001). Colostrum yield was also positively correlated with calf birth weight (r = 0.31, P < 0.001) and whole placental dry weight (r = 0.26, P = 0.007), but tended to be negatively correlated with calf birth weight relative to dam BW (r = -0.14, P = 0.09). Gestation length had no relationship (P = 0.31) with colostrum yield. Overall, colostrum yield and quality are negatively affected in young and thin beef dams. In addition, both dam and calf weight have positive relationships with colostrum yield, likely mediated by endocrine action associated with placental size. [ABSTRACT FROM AUTHOR]

Data from 9 calving experiments were used to investigate relationships of dam, calf, and colostrum factors with passive transfer in beef calves. Serum was collected at 48.33 ± 1.25 (SD) h of age for 313 calves, and single rear quarter colostrum yields were determined pre-suckling for dams of 117 calves. Serum and colostrum IgG concentrations were determined by ELISA. Relationship of serum IgG with colostrum variables was determined using Pearson correlation coefficients. Serum IgG was positively correlated (P ≤ 0.002) with colostrum IgG (r = 0.47) and protein (r = 0.45) concentrations and colostrum total IgG (r = 0.28) but tended to be negatively correlated (r = -0.17, P = 0.06) with colostrum yield. Based on passive transfer thresholds in the literature, 3 calves (0.96%) had < 8 mg/mL serum IgG, 16 calves (5.1%) < 16 mg/mL, and 43 calves (13.7%) had < 24 mg/mL. For this analysis, calves with serum IgG < 24 mg/mL at 48 h were considered to have failure of passive transfer (FPT). Continuous variables (dam BW and calf size, 48-h serum chemistry panel, and time to stand) were compared for FPT versus non- FPT calves using a mixed model with FPT class (fixed effect) and experiment (random effect). Calves with FPT had less (P ≤ 0.03) circulating triglycerides, glucose, calcium, magnesium, total protein, globulin, and gamma-glutamyl transferase but greater (P ≤ 0.001) circulating non-esterified fatty acids, sodium, chloride, and total bilirubin than non-FPT. Effects of categorical variables on calf 48-h serum IgG were determined using separate mixed models with variable (fixed) and experiment (random). Primiparous dams gave birth to calves that had less (P = 0.05) serum IgG at 48 h than multiparous dams. Calves born to moderate dams (BCS = 5) had less (P = 0.007) serum IgG than those born to fleshy dams (BCS ≥ 6) and tended to have less (P = 0.08) serum IgG than calves born to thin dams (BCS < 5). Calf sex, calving season, calving difficulty score, and vigor score at 10 min did not affect (P ≥ 0.19) serum IgG. Relationships of calf 48-h serum IgG with continuous variables was also determined using Pearson correlation coefficients, and only r ≥ 0.20 or ≤ -0.20 are reported. Serum IgG was positively correlated (P ≤ 0.005) with 48-h serum total protein (r = 0.75), globulin (r = 0.76), gamma-glutamyl transferase (r = 0.32), and potassium (r = 0.20). Serum IgG was negatively correlated (P < 0.001) with gestation length (r = -0.22) and 48-h serum albumin (r = -0.43), sodium (r = -0.24), and total bilirubin (r = -0.27). Overall, beef calves in this dataset generally had successful passive transfer that was associated with several dam, calf, and colostrum factors. [ABSTRACT FROM AUTHOR]

Fall-calving Hereford-SimAngus heifers [single-sired; body weight (BW): 451 ± 28 (SD) kg; body condition score (BCS): 5.4 ± 0.7] bred to a single sire were individually-fed 100% (control; CON; n = 12) or 70% (nutrient restricted; NR; n = 13) of estimated metabolizable energy and metabolizable protein requirements for maintenance, pregnancy, and growth from d 160 of gestation to calving. Post-calving, all females were fed to meet lactational nutrient requirements until weaning. From d 1 to 147 of lactation, dams were individually fed chopped tall fescue hay and supplemented in Calan gates to constrain diets of calves to milk only. After d 147, dams and calves were managed as a group in drylots, and calves could access the tall fescue hay offered to their dams. Bull calves (CON; n = 8; NR; n = 9) were castrated at 176 ± 3 (SD) d of age to represent a later pre-pubertal growth stage that is indicative of post-pubertal testis size. The epididymis and pampiniform plexus were removed, and calipers were used to determine the length and perpendicular widths of each testis. Testis weight was recorded, and testis volume was determined by water displacement in a graduated cylinder. Testis parenchyma was fixed in neutral buffered formalin for histological analyses. Seminiferous tubule diameter was measured on perpendicular diameters of 40 randomly chosen tubules with a visibly round cross-section. Data were analyzed with late gestational nutritional plane and calving date as fixed effects. Birth weight of bull calves was not affected (P > 0.99), but we previously reported that late gestational nutrient restriction decreased (P ≤ 0.04) milk production by 15% during the first 147 d of lactation. By d 63 of age, bull calves born to previously NR dams weighed less (P = 0.03) than bull calves born to CON dams. Body weight remained different (P ≤ 0.04) until castration, at which point bull calves born to previously NR dams weighed 14% less (P = 0.02) than bull calves born to CON dams. Average testis diameter was less (P = 0.03), and average testis length tended to be less (P = 0.07) for calves born to previously NR dams. Paired testes weight and volume were less (P ≤ 0.05) for calves born to previously NR dams, but testes weight relative to calf BW and average seminiferous tubule diameter were not affected (P ≥ 0.20) by late gestational nutritional plane. In the current study, pre-pubertal bull calves born to NR dams had decreased testis size, but it is difficult to delineate if this is a direct effect of gestational undernutrition on fetal development or its indirect effect on post-weaning development due to decreased milk production. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the influence of melatonin supplementation in pregnant beef cattle grazing toxic, endophyte-infected tall fescue (E+) on post-calving dam body weight (BW), milk production, and preweaning growth of steer calves. Multiparous cows were artificially inseminated with sex-sorted semen (Y chromosome-bearing sperm) from a single Red Angus sire and maintained on pastures free from E+ fescue prior to the start of the treatment period. Pregnant cows were assigned to one of three treatment groups with two replications per treatment: non-toxic, novel endophyte-infected (NE+) tall fescue without melatonin supplementation (NE+/NM; n = 15), E+ fescue with melatonin supplementation (E+/M; n = 16), and E+ fescue without melatonin supplementation (E+/NM; n = 18). The treatment period was over 70 d between May and July (d 147 ± 1 to 217 ± 1 of gestation). A commercially available feed was mixed with melatonin (100 µg/kg BW) or without melatonin and hand-fed to each cow daily. At the conclusion of the treatment period (56 ± 18 d before parturition), cattle were moved to a single group and maintained on pastures free from E+ fescue for the remainder of the study. Dams and steer calves were weighed at d 0, 28, 56, 84, 112, 140, and 168 relative to calving (d 0 = calving). Four-hour milk yields on d 28 ± 3 and d 56 ± 3 were used to estimate daily milk volume and weight. Dam and calf BW were analyzed using the MIXED procedure of SAS specific for repeated measures with treatment, time, and the interaction as fixed effects and replicate as random. Calf birth weight, dam milk volume, and dam milk weight were analyzed using the MIXED procedure of SAS with treatment as a fixed effect and replicate as random. On d 28, estimated daily milk volume and weight were decreased (P < 0.05) in E+/NM dams relative to NE+/NM dams. On d 56, estimated daily milk volume and weight were decreased (P < 0.03) in E+/NM and E+/M dams relative to NE+/ NM dams. There was an effect of time for dam and calf weights (P < 0.01). There was a treatment by time interaction for calf body weight, with calves born to E+/NM dams having decreased body weight relative to calves born to NE+/NM and E+/M dams from d 112 to d 168 (P = 0.02). There were no other effects of treatment, time, or the interaction (P > 0.05). These data suggest melatonin supplemented to pregnant crossbred multiparous beef cows grazing endophyteinfected tall fescue during mid-late gestation may increase preweaning growth of steer calves. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effects of peripartum supplementation of a methionine hydroxy analogue (MHA) to primiparous, spring-calving beef females on dam and progeny performance. Angus heifers (n  = 60) were blocked by expected parturition date, stratified by body weight (BW) and body condition score (BCS), and randomized to 1 of 15 pens. Pens were randomly assigned to 1 of 3 dietary treatments: a basal diet supplemented with 0 (M0), 15 (M15), or 30 (M30) g/animal/d of MHA (provided as MFP feed supplement, Novus International Inc. St. Charles, MO). Diets were fed from 45 ± 13 (SD) d pre-calving through 81 ± 13 d postpartum (DPP), after which all cow–calf pairs were managed as a single group on pasture until weaning (199 ± 13 DPP). Dam BW, BCS, and blood samples were taken at 6 predetermined timepoints. Progeny data were collected at birth, 2 intermediate timepoints, and at weaning. Milk samples were collected for composition analysis at 7 ± 2 DPP and at 55 ± 5 DPP. Serial progesterone samples were analyzed to establish resumption of cyclicity, and ultrasonography was performed at 55 ± 5 DPP to evaluate ovarian function. Cows were bred via artificial insemination at 82 ± 13 DPP and subsequently exposed to bulls for a 55-d breeding season. Pen was the experimental unit, and preplanned orthogonal contrasts were tested (linear effect and M0 vs. M15 + M30). Dam BW and BCS were not affected by treatment (P  ≥ 0.29) throughout the study. Week 1 milk fat concentration increased linearly (P  = 0.05) and total solids tended to increase linearly (P  = 0.07) as MHA increased; however, no other milk components were affected (P  ≥ 0.16). Treatment did not affect (P  ≥ 0.16) dam reproductive parameters or progeny growth from birth until weaning. Post-calving, circulating methionine equivalents tended to linearly increase (P  = 0.10) with increasing MHA supplementation. At breeding, plasma urea N linearly decreased (P  = 0.03) with increased supplementation of MHA, and plasma non-esterified fatty acids were less (P  = 0.04) in MHA-supplemented dams compared with dams receiving no MHA. Maternal circulating glucose, glutathione peroxidase, and thiobarbituric acid-reactive substances were not affected (P  ≥ 0.15) by treatment at any point. These data indicate that peripartum supplementation of MHA may increase milk fat composition shortly after calving, but MHA supplementation did not improve progeny growth or dam reproductive performance in the current study. [ABSTRACT FROM AUTHOR]

To determine effects of dam parity on perinatal nutrient availability in beef cattle, data and samples were collected from 18 primiparous and 35 multiparous spring-calving Sim-Angus dams and their calves. Time to stand was recorded and neonatal vigor assessed. Jugular blood was collected from a subset of calves at 0 (post-standing and pre-suckling) 6, 12, 24, 48, and 72 h of age, and blood chemistry panels were completed. Expelled placentas were dissected, dried, and weighed. Prepartum maternal circulating glucose, non-esterified fatty acids (NEFA), triglycerides, and urea N were analyzed. All statistical models included the fixed effect of dam parity, and calf sex (when P ≤ 0.25) was included for calf and placental variables. Effects of sampling hour, and parity × hour were included for calf metabolites over time using repeated measures. Multiparous dams had greater body weight prepartum (P < 0.001) but similar (P = 0.25) body condition score. Maternal circulating urea N and triglycerides were greater (P ≤ 0.05) in multiparous dams pre-calving. Calves born to primiparous dams weighed 10% less (P ≤ 0.04) at birth with smaller (P ≤ 0.01) heart and abdominal girths. Cotyledonary, intercotyledonary, and total placental masses were less (P ≤ 0.05) for primiparous dams. Dam parity did not affect (P ≥ 0.58) calf time to stand, vigor score at 10 min, or rectal temperature. Serum glucose was greater (P = 0.03) at 0 h but less (P ≤ 0.04) at all other hours in calves from primiparous dams. Calves from primiparous dams had greater (P ≤ 0.02) serum NEFA at 6, 12, and 24 h although plasma triglycerides were greater (P < 0.001) at 6 h. Calves from primiparous dams had greater (P ≤ 0.04) serum urea N at 12 h and creatinine at 12 and 24 h. Plasma insulin was greater (P ≤ 0.04) in calves from multiparous dams at 12, 48, and 72 h, but parity did not affect (P ≥ 0.18) serum total protein or plasma cortisol. Serum aspartate aminotransferase was greater (P ≤ 0.04) at 6 and 24 h, creatine kinase was greater at 24 h, and gamma-glutamyl transpeptidase was less (P ≤ 0.04) at 6, 12, and 24 h, for calves from primiparous dams. Calves born to primiparous dams had greater (P ≤ 0.02) total bilirubin and direct bilirubin at 12 and 24 h. Data indicate that calves born to first-parity heifers had decreased perinatal nutrient availability, resulting in reduced fetal and placental growth, as well as greater energy reserve mobilization and metabolic indicators of stress as neonates. [ABSTRACT FROM AUTHOR]