Translational Animal Science最新文献

Bovine Ephemeral Fever (BEF), caused by an arthropod-borne rhabdovirus, is widespread in tropical and subtropical regions. It affects cattle with symptoms of fever, lameness, inappetence and in some situations can result in mortality. The goal of this study is to determine if accelerometer data can be used to identify the behavior patterns that occur when cattle become ill from BEF. Eight heifers in a separate experiment were monitored with 3-axis accelerometers sensors. Movement variation (MV) was calculated from accelerometer data (25 Hz) using 1-min epochs and then averaged hourly. Two different approaches, cosine similarity (CS) and deviation from previous behavioral patterns, were developed to autonomously detect patterns and recognize the onset of sickness in cattle using accelerometer data. Analyses show that one heifer had behavioral changes one day before the manager observed BEF, and another heifer had behavioral changes on the same day the manager observed BEF. The other six heifers did not display any BEF symptoms. To validate the efficacy of our analytical approaches, we employed them on a separate commercial herd of 73 cows where 4 of the 27 monitored cows were observed with BEF symptoms. Predictions were either on the day or even the day prior to the manager's observation and diagnosis. There were likely no false positives in the first or second trials using the deviation algorithm with $sum\_deviation$ formula, but there were several false positives with the other algorithms. These case studies demonstrate the potential of accelerometer data to autonomously detect disease onset, in some cases before it was apparent to the human observer. However, more research is needed to minimize false positives that may occur from other similar diseases, abnormal weather events or cyclical changes in behavior such as estrus is required.

Our objective was to compare beta-agonist feeding strategies and evaluate Experior (EXP) with added days on feed (DOF) for live growth performance and carcass outcomes. Steers (n = 2,517; initial BW = 336 ± 23 kg) were allocated to 36 pens in a randomized, complete-block design and assigned to 1 of 6 treatments. Treatments were negative control (no beta-ligand; CON), Optaflexx (ractopamine hydrochloride, 300 mg·head^-1·day^-1 for 35 d; OPT), and Experior (lubabegron fumarate, 36 mg·head^-1·day^-1 for 56 d + 4 d removal; 0EXP) with all three treatments fed for 198 d. Remaining treatments were fed EXP for same duration as 0EXP, but total DOF were adjusted by -14 d (-14EXP), +14 d (+14EXP) and +28 d (+28EXP). Statistical analyses were conducted using mixed models; treatment was the fixed effect, block was a random effect, means were separated with the Tukey-Kramer adjustment, and contrasts were calculated to test linear or quadratic effects of EXP across DOF. No treatment differences (P ≥ 0.72) were observed for daily dry matter intake. Calculated cumulative ammonia (NH₃) gas emissions (CCAGE) expressed either as total NH₃ emitted (g) or NH₃ emitted per kg of BW or HCW was reduced (P < 0.01) by 5.6-8.5%, 5.1-10.7%, and 6.3-13.6%, respectively for 0EXP, +14EXP and +28EXP compared to CON. Carcass ADG of 0EXP steers was 6.8% greater (P < 0.01) than CON, which had similar (P ≥ 0.10) ADG to OPT, +14EXP, and +28EXP steers. Carcass G:F of 0EXP steers was improved 5.0% compared to CON (P = 0.01) and was not different (P ≥ 0.10) from OPT, -14EXP or +14EXP steers. Hot carcass weight of 0EXP, +14EXP, or +28EXP steers was 14-37 kg heavier (P < 0.01) than CON, which did not differ (P = 0.81) from OPT. Steers fed EXP had 1.15-2.5% point increase (P < 0.01) in dressed yields. Longissimus muscle area was 4.03-6.23 cm² larger (P < 0.01) in steers fed EXP compared to CON, which tended to differ (P = 0.08) from OPT. Marbling score was 31-39 points lower (P ≤ 0.02) for -14EXP compared to CON and OPT, whereas 0EXP tended (P = 0.09) to differ from CON and +14EXP and +28EXP were similar (P ≥ 0.28) to CON and OPT. Slice shear force values were 20.1% greater (P < 0.02) for +14EXP compared to CON, whereas 0EXP tended (P = 0.09) to be greater and +28EXP, -14EXP and OPT were similar (P ≥ 0.28) to CON. This study illustrates EXP decreased CCAGE and increased HCW with minimal quality changes when fed the last 56 d on feed.

Treatment for enteric parasites is a common practice in beef cattle, yet little data is known about the prevalence of nematode and trematode parasite infections in beef cattle in the western United States. Likewise, the data on the efficacy of deworming practices and the presence of anthelmintic resistance (AR) of these parasites in this region is sparse. The current study collected evidence for the presence of nematode and trematode parasites in 18 herds of young beef cattle grazing either dryland or irrigated pasture in northern California as well as on efficacy and evidence of AR in a subgroup of herds. We found variable levels of fecal egg counts (FEC) ranging from 6 to 322 for the arithmetic mean eggs per gram (EPG) in the tested cattle groups. There was no difference in the number of EPG between herds grazing dryland or irrigated pasture (P = 0.54). We did not find any evidence for liver flukes or lungworms in the tested cattle. There was evidence of AR to macrocyclic lactones in all eight herds where fecal egg count reduction tests (FECRT) were performed, however due to types and execution of treatment applications and sample sizes, these results need to be interpreted with caution. The most common genus of third stage larvae in coproculture testing before treatment was Cooperia (between 55% and 98% of larvae) as well as post treatment for those herds undergoing FECRT (between 50% and 96%). Ostertagia was the second most frequent genus of larvae found in coproculture testing making up between 0% and 27% of larvae before treatment and between 5% and 50% of larvae after treatment. Anthelmintic practices in beef herds in northern California and likely in a larger geographic area in the western United States need to be updated in order to continue effective use of the currently available drugs.

The production of crossbred beef × dairy (B × D) calves is increasing; however, evaluation of pre-weaning feeding strategies for B × D calves is limited. We hypothesized that both male and female B × D calves fed added fat and protein through milk replacer would have increased muscle growth, muscle fiber cross-sectional area, average daily gain, BW, and morphometric measurements. We also hypothesized that calves fed the additional fat and protein milk replacer would have upregulation of regulatory genes involved in muscle hypertrophy. SimAngus × Holstein calves (n = 42) were assigned to one of two milk replacers: 30.0% crude protein (CP), 32% crude fat (CF) milk replacer (HPHF, n = 11 males, 11 females), or 22% CP, 20% CF milk replacer (CON, n = 10 males, 10 females) from 0 to 8 wk of age. B × D calves were weighed at birth and weekly thereafter. At week 2 and 8, longissimus muscle biopsies were collected for muscle fiber cross-sectional area (CSA) or gene expression analysis. Ultrasounds were performed at 4 and 8 wk of age to quantify ribeye area (REA), and backfat and rump fat thickness. Morphometric measurements, BW, CSA, and ultrasound data were analyzed with PROC MIXED with animal as the subject and fixed effects of milk replacer, age, sex, and their interactions. Gene expression data were analyzed in R Studio. Calves that consumed the HPHF milk replacer were heavier than calves consuming the CON milk replacer (HPHF: 70.7 ± 0.39 kg; CON: 68.5 ± 0.41 kg; P < 0.01). At 8 wk of age, HPHF calves tended to have 14% larger muscle fiber CSA than CON calves (P = 0.06). No differences due to diet were observed for REA or fat thickness (P ≥ 0.38). Expression of MyoD tended to be 34% greater in CON females than HPHF females at 2 wk (P = 0.06), but at 8 wk, HPHF females tended to express 39% more MyoD than CON females (P = 0.09). Myogenin expression was 3% greater in CON calves than HPHF calves at 2 wk (P = 0.02), and CON females tended to express 52% more IGF-1 than HPHF females (P = 0.07). Feeding a milk replacer with a protein and fat content similar to beef cow milk improves B × D calf growth compared with a conventional milk replacer with less protein and fat. Improvements in early growth may improve B × D carcass quality and quantity, with the potential to increase return to the producer.

Enterotoxigenic Escherichia coli (ETEC) is a leading cause of postweaning diarrhea (PWD) and mortality of weaned pigs. The objective of this study was to evaluate genetic resistance of the polymorphism at nucleotide 307 (M307) in the FUT1 gene, to F18 E. coli infection considering different genotypes. A total of 179 pigs were used for this study. Pigs were genotyped for susceptibility to F18+ E. coli prior to the trial. Treatments included: genotype M307^GA-heterozygous for E. coli susceptibility (A), genotype M307^GG-homozygous E. coli susceptibility (B), or genotype M307^AA-homozygous for E. coli resistance (C). Pigs were weighed, assigned to pens based on genotype, and allowed to acclimate for 3 d prior to the challenge. On days 4, 5, and 6, pigs were inoculated intraorally at the oropharynx with an F18+ E. coli isolate at a geometric mean concentration of 9.8 × 10⁹. Growth rate (average daily gain [ADG]), feed intake (average daily feed intake), and gain-to-feed ratio (G:F) were calculated by pen. All pigs were humanely euthanized at the end of the trial. Two fixed sections of ileum and distal jejunum were collected from a subpopulation and tested by in situ hybridization (ISH) to evaluate F18+ E. coli adherence. Fresh ileum samples were used for enumeration of F18, total E. coli, and total bacteria by real-time polymerase chain reaction. Mortality rates during the trial were 26.7% for genotype A, 18.3% for genotype B, and 0.0% for genotype C (P < 0.01). Starting weights prior to inoculation were not different (P = 0.29) among genotypes. Overall, pigs from genotype C grew 223 g/d faster (P = 0.04) than genotype A. Pigs from genotype C tended to grow 185 g/d faster (P = 0.09) than genotype B. G:F for genotype C (0.74) was 23% greater (P < 0.01) than G:F for genotype A (0.60) and tended to be 12% greater (P = 0.07) than genotype B (0.66). There were no differences in ADG or G:F between genotypes A and B. F18-specifc Cq units were decreased by 7.74 and 6.47 in genotypes A and B compared with genotype C (P ≤ 0.03). Signal by ISH was increased by 14.0-fold in genotype A compared with genotype C (P = 0.02). Adherence was not different among genotypes (P = 0.40). Genotype A had greater mortality and poorer growth performance than genotype B or C. Genotype C had no mortalities during the trial, grew faster, was more feed efficient, and had less F18 E. coli in the ileal mucosa compared with genotype A. Resistant genotypes provide an opportunity to reduce PWD and mortality due to an F18+ E. coli infection.

This study evaluated how the backgrounding diet can affect water intake, animal performance and water and feed efficiency of steers fed finishing diets based on grains or forages. Twenty-four crossbred Angus steers (298 ± 10.2 kg) were fed during backgrounding either a moderate (MP, n = 12; triticale hay only, 9.1%crude protein [CP], 1.07 Mcal/kg net energy available for maintenance [NEm], and 0.52 Mcal/kg net energy available for gain [NEg]) or high plane of nutrition (HP, n = 12; 85% alfalfa hay and 15% beardless wheat hay, 12.62%CP, 1.23 Mcal/kg NEm, and 0.66 Mcal/kg NEg) during the background phase (85 d). After this period, steers were assigned to two finishing phase groups containing half of the animals from each backgrounding diets. During the finishing phase, animals were fed either a forage-based (Alfalfa hay; CP: 20.8% DM, NEm: 1.47 Mcal/kg, NEg: 0.88 Mcal/kg) or a grain-based diet (80% whole corn and 20% wheat hay; CP: 10.6% DM, NEm: 1.96 Mcal/kg, NEg: 1.31 Mcal/kg). There was no interaction between the effects of the previous plane of nutrition [(moderate (MP) or high (HP)] and finishing diets (forage or grain-fed) on any of the variables studied (P > 0.05). Animals backgrounded on MP were lighter and had a lower DMI when compared with HP (P < 0.01). However, no differences were observed on the drinking water intake (DWI) between MP and HP (P > 0.05). HP animals were more efficient in gross water efficiency (P < 0.01), but less efficient on residual feed intake (P < 0.05), compared to MP animals. During the finishing phase, forage fed animals had a greater DMI and DWI compared with grain-fed animals (P < 0.01), however, no differences were observed on the final BW (P > 0.05). Grain-fed animals were more efficient for water and feed intake and had a greater marbling score (P < 0.01) compared to forage-fed. Animals fed on HP and finished in a grain-fed diet had the least DWI (P < 0.05) and greatest body condition score (P < 0.05), marbling score (P < 0.01) and rib depth (P < 0.05). In the first 20 d of the finishing period, the previous plane affected the variables ADG, DMI, CPi, and DWI (as kg DMI and CP) in the finishing plane. Altogether, our results highlight the individual effects of backgrounding and finishing systems on DWI and the efficiency of finishing animals, as well as the importance of providing adequate nutrition during the earlier stages of life.

A study was conducted to assess growth performance, methane (CH₄) emissions, and feeding behavior of feedlot steers consuming backgrounding and finishing diets with an essential oil blend (EO), monensin (Mon), and their combination (EO + Mon). The study was structured as a 2 × 2 factorial, with two feed additive treatments (Control, EO) and two monensin treatments (no Monensin, Monensin). One hundred Angus × steers were evenly distributed across each treatment into four pens, and each dietary phase consisted of four, 28-d periods. Using the GreenFeed system to estimate CH₄ yield (g CH₄/kg dry matter intake [DMI]), the mean CV (coefficient of variation) within the same steer across measurement periods was 14.0% and 15.2% for the backgrounding and finishing phases, respectively. The mean CV of CH₄ production for steer within period and time-of-day block was up to 83.4% and 102.9% for the backgrounding and finishing phases, respectively. There was no difference in overall average daily gain (P ≥ 0.22) or gain:feed ratio (P ≥ 0.26) with EO or Monensin during the backgrounding or finishing phases. There were variable period effects on CH₄ emissions, but overall control had lower (EO × Mon; P ≤ 0.01) CH₄ production, yield, and CH₄ energy as a percentage of gross energy intake (GEI) (Ym, Mcal CH₄ % GEI), during the backgrounding phase. During the finishing phase, CH₄ yield (EO × Mon; P = 0.02) and Ym (EO × Mon; P ≤ 0.01) were greatest in the EO + Mon treatment. Monensin, irrespective of EO, decreased DMI (P < 0.01) and eating rate (P = 0.01), and increased intermeal interval (P < 0.01) for the backgrounding phase. In the finishing phase, Monensin decreased (P < 0.01) DMI, variation of DMI (EO × Mon), meal size, and eating rate. Number of GreenFeed visits was negatively (P < 0.01) correlated with all feeding behavior metrics in the finishing phase. In conclusion, supplementation of EO or Monensin and their combination into backgrounding and finishing diets of feedlot steers had no effect on overall feedlot performance or CH₄ emissions. Additionally, the high variability in CV of CH₄ production and yield suggests a need to improve the accuracy and precision of the GreenFeed system for estimating enteric CH₄ emissions from cattle.

Heat stress (HS) is widely recognized by researchers and veterinarians as a major issue impacting swine health, productivity, and welfare, but there is limited understanding of how HS is perceived and managed at the farm level. Therefore, the study objective was to assess U.S. swine farm managers' perceptions of HS impacts, thresholds, and management for multiple pig categories including preweaned pigs, nursery pigs, grow-finish pigs, market pigs, nonpregnant and gestating sows, lactating sows, and mature boars. Sixty-two swine farm managers completed an electronic Qualtrics survey, presented in both English and Spanish, which included questions on perceived HS thresholds, ventilation setpoints, mitigation practices, and environmental management support tools. Respondents rated their agreement with HS impacts on productivity, health, and welfare using a Likert scale, and Pearson's correlations were used to establish relationships between responses. A majority of respondents agreed or strongly agreed that HS negatively affects pig productivity (87.1%), health (83.9%), and welfare (85.5%). However, perceived HS thresholds were variable across pig categories including preweaning pigs (31.22 ± 3.59 °C), nursery pigs (31.46 ± 3.79 °C), grow-finish pigs (28.16 ± 4.27 °C), market pigs (26.22 ± 5.56 °C), nonpregnant sows (27.77 ± 3.81 °C), gestating sows (26.99 ± 3.34 °C), lactating sows (26.71 ± 3.08 °C) and mature boars (26.61 ± 3.99 °C). The standard deviations for reported thresholds ranged from ±3.08 to ±5.56 °C, underscoring the variability in perceptions among respondents. This variability extended to ventilation temperature setpoints with high ventilation temperature setpoints of 24.34 ± 3.75 °C and 25.41 ± 2.80 °C, and low ventilation temperature setpoints of 17.32 ± 3.10 °C and 18.86 ± 2.96 °C for gestation barns and farrowing barns, respectively. Finally, a majority of producers (64.5%) agreed or strongly agreed that a decision support tool for improved HS management would be beneficial to their operation. Producer responses emphasize the need for clearer guidelines and more consistent application of HS management practices to optimize swine health, productivity, and welfare across different production stages.

Two experiments evaluated the effects of an injectable trace mineral (ITM) solution at weaning on trace mineral (TM) status, inflammatory and antioxidant responses, grazing behavior, response to vaccination, and growth of beef calves. Experiment 1 used 86 Nellore calves (40 females and 46 males; body weight [BW] = 198 ± 30.8 kg; 8 ± 1 mo of age) weaned (day 0) and assigned into one of two treatments: saline (0.9% NaCl) or ITM (60 mg of Zn/mL, 15 mg of Cu/mL, 5 mg of Se/mL, and 10 mg of Mn/mL). Saline and ITM were administered subcutaneously at a dose of 1 mL/45 kg of BW. On day 0, calves were vaccinated against infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI₃), bovine viral diarrhea virus types 1 and 2 (BVDV-1 and 2) and bovine respiratory syncytial virus (BRSV). Blood samples and BW were collected on days 0, 3, 8, 15, 51, and 100, and grazing behavior was evaluated on days 1, 2, 4, 5, 6, 7, and 9. The ITM did not affect (P ≥ 0.56) serum mineral concentrations of Zn and Cu, but decreased (P ≤ 0.02) plasma concentrations of cortisol on days 3 and 8 and haptoglobin on day 3. The ITM increased (P < 0.01) plasma concentration of superoxide dismutase on days 8, 15, and 51 and tended to decrease (P = 0.08) plasma concentration of glutathione peroxidase on day 3. Furthermore, there were no effects of treatment (P ≥ 0.14) on most of the behavior variables evaluated, ITM reduced (P = 0.01) the seeking time on days 0 and 4. Furthermore, ITM tended to increase (P = 0.10) the serum titer concentration against IBR on days 15 and 51 but did not affect (P ≥ 0.12) titer concentration against PI₃, BVDV-1, and 2, and growth. Experiment 2 used 50 Brangus male calves (BW = 264 ± 34.1 kg; 8 ± 1 mo of age) weaned on day 0, vaccinated against respiratory diseases, stratified by BW, and randomly assigned to saline or ITM as described in experiment 1. Liver samples were collected on days 0, 14, and 197, blood samples on days 0, 14, and BW on days 0, 14, 44, 78, 122, 162, and 197. The ITM increased (P ≤ 0.03) the liver concentration of Cu and Se on day 14 but did not affect (P ≥ 0.17) the liver concentration of Zn and Mn. In addition, ITM increased (P = 0.05) the serum titer concentration against BVDV-2 but did not affect (P ≥ 0.20) the titer concentrations against IBR, PI₃, BVDV-1, and BRSV, and did not affect (P ≥ 0.29) the growth. In conclusion, ITM application at weaning improved Cu and Se status, enhanced antioxidant and immune responses, and reduced stress and inflammation in calves, though it did not affect growth.

Hempseed meal (HSM) is a potential alternative feedstuff for livestock due to its high protein content, but it has not been approved for animal feed in the United States due to safety concerns. This study was conducted to determine the effects of HSM on feed intake, growth performance, serum biochemistry, ruminal papillae morphology, ruminal fermentation profiles, and carcass characteristics of intact male goats. Thirty-six Boer × Spanish intact male goats were randomly assigned to one of four experimental diets (n = 9 goats/diet): 0%, 10%, 20%, and 30% HSM on as-fed basis. Diets were formulated to be isonitrogenous and fed free-choice for ad libitum consumption in the 60-day experiment. Linear and quadratic effects of different concentrations of HSM were determined. Total feed intake, crude protein intake, ruminal papillae morphology (papillae density, length, width, absorptive surface area, stratum corneum, and stratum granulosum thickness), carcass traits (longissimus muscle area, body wall thickness, backfat thickness, shrink percentage), and serum concentrations of most metabolites were similar among treatments (P > 0.05). Intake of acid detergent fiber (ADF) and nitrogen detergent fiber (NDF) increased linearly (P < 0.05) with increasing inclusion of HSM in the diet. Average daily gain (ADG), gain-to-feed ratio, and dressing percentage decreased linearly (P < 0.05) with an increasing percentage of HSM in the diet. Similarly, concentrations of propionic, butyric, iso-butyric, valeric, and isovaleric acids in ruminal fluid decreased linearly (P < 0.05) with an increasing percentage of HSM in diet, whereas concentration of acetic acid and total volatile fatty acids in ruminal fluid tended to decrease linearly (P-value nearly 0.10) with an increasing percentage of HSM in diet. The level of blood urea nitrogen increased linearly (P < 0.05) with increasing concentration of HSM, but values were within the normal range for goats. Findings from the serum metabolite analysis and ruminal papillae morphometrics suggest that goats can be fed HSM at a concentration of up to 30% in their diet. However, growth performance results indicate that further cost-benefit analysis is required to compare HSM with other commonly used protein sources such as soybean meal. These findings will be useful for legal bodies to review during the approval process of HSM as a feed ingredient for goats in the United States.