Translational Animal Science最新文献

The aim of the study was to deploy computer vision models for real-time detection of digital dermatitis (DD) lesions in cows using Android or iOS mobile applications. Early detection of DD lesions in dairy cows is crucial for prompt treatment and animal welfare. Android and iOS apps could facilitate routine and early DD detection in cows' feet on dairy and beef farms. Upon detecting signs of DD, dairy farmers could implement preventive and treatment methods, including foot baths, topical treatment, hoof trimming, or quarantining cows affected by DD to prevent its spread. We applied transfer-learning to DD image data for 5 lesion classes, M0, M4H, M2, M2P, and M4P, on pretrained YOLOv5 model architecture using COCO-128 pretrained weights. The combination of localization loss, classification loss, and objectness loss was used for the optimization of prediction performance. The custom DD detection model was trained on 363 images of size 416 × 416 pixels and tested on 46 images. During model training, data were augmented to increase model robustness in different environments. The model was converted into TFLite format for Android devices and CoreML format for iOS devices. Techniques such as quantization were implemented to improve inference speed in real-world settings. The DD models achieved a mean average precision (mAP) of 0.95 on the test dataset. When tested in real-time, iOS devices resulted in Cohen's kappa value of 0.57 (95% CI: 0.49 to 0.65) averaged across the 5 lesion classes denoting the moderate agreement of the model detection with human investigators. The Android device resulted in a Cohen's kappa value of 0.38 (95% CI: 0.29 to 0.47) denoting fair agreement between model and investigator. Combining M2 and M2P classes and M4H and M4P classes resulted in a Cohen's kappa value of 0.65 (95% CI: 0.54 to 0.76) and 0.46 (95% CI: 0.35 to 0.57), for Android and iOS devices, respectively. For the 2-class model (lesion vs. non-lesion), a Cohen's kappa value of 0.74 (95% CI: 0.63 to 0.85) and 0.65 (95% CI: 0.52 to 0.78) was achieved for iOS and Android devices, respectively. iOS achieved a good inference time of 20 ms, compared to 57 ms on Android. Additionally, we deployed models on Ultralytics iOS and Android apps giving kappa scores of 0.56 (95% CI: 0.48 to 0.64) and 0.46 (95% CI: 0.37 to 0.55), respectively. Our custom iOS app surpassed the Ultralytics apps in terms of kappa score and confidence score.

Calf processing events have important animal health, management, and sociocultural roles in the beef cattle industry. In western Canada, the three most commonly used methods for spring processing are roping and wrestling (RW), roping and Nord fork (NF), and tilt table (TT). The objective of this study was to understand the preferences and perceptions of handling event participants about calf handling and restraint methods commonly used during western Canadian beef calf processing events during the spring season. Data were collected using a mixed-methods online questionnaire. Quantitative analysis was used to describe the study participants and determine preference rankings. Qualitative, thematic analysis was used to explore participants' perceptions about the common handling and restraint methods and to identify values within and across participants. The majority of participants were farm hands or staff members (92.8%), followed by owners (4.9%), family members (1.4%), friends (0.5%), and others (0.4%). The most preferred method to use was RW, and TT was the least preferred (χ² = 3239.1, df = 6, p < 0.001). Participants shared values regarding calf safety and stress, processing efficiency, convenience, human safety, and labor intensity when explaining their preference to use calf handling and restraint methods for spring processing. Responses highlighted the need for understanding and skill in low stress handling and processing tasks in order for any of the methods to be effective. These values identify aspects to address when developing best practice recommendations for calf handling and restraint. Furthermore, focusing communication through the lens of these shared values will likely positively engage participants in extension efforts and community discussions.

Social behavior in cattle can be measured by how often and for how long they interact with each other. This information can be used to guide management decisions, identify sick animals, or model the spread of diseases. However, visual observation of proximity events is time-demanding and challenging, especially for rangeland cattle spread over a large area. Although proximity loggers can potentially overcome these challenges remotely, it is unknown how accurate these devices are in recording proximity events among beef bulls. The objectives of this study were: 1) to determine the accuracy of Lotek LiteTrack LR collars with built-in proximity loggers to identify proximity events among bulls and 2) to determine the accuracy of Lotek LiteTrack LR collars to identify proximity events between bulls wearing collars and bulls wearing the Lotek V7E 154D ear tag proximity transmitter. Collars were deployed in 12 bulls in 2021 (Experiment 1), and 10 bulls (5 collars and 5 ear tags) in 2023 (Experiment 2). Videos were recorded of bull behavior in both years to compare proximity observed to proximity recorded by the loggers. Sensitivity (Se), specificity (Sp), precision (Pr), and accuracy (Ac) were calculated after computing true positives (TP), false positives (FP), false negatives (FN), and true negatives (TN). The interquartile range method was used to detect outliers. As collars work as both a transmitter and receiver in Exp. 1, reciprocity was assessed by the Concordance Correlation Coefficient (CCC) as an indirect measure of reliability. In Exp. 1, most observations were TN (95.13%), followed by FN (4.11%), TP (0.70%), and FP (0.06%). A high Sp (median = 1.0; 95% CI = 1.0 to 1.0), Pr (1.00; 0.72 to 1.0), and Ac (0.96; 0.95 to 0.97), and low Se (0.10; 0.06 to 0.21) were observed. A high reciprocity agreement (0.93; 0.89 to 0.96) was also observed. Likewise, in Exp. 2 most observations were TN (85.05%), followed by FN (9.94%), TP (4.36%), and FP (0.65%), while high Sp (0.99; 0.99 to 1.0), Pr (0.89; 0.80 to 0.92), and Ac (0.95; 0.81 to 0.95), and low Se (0.35; 0.24 to 0.61) was observed. The Pr of two loggers in Exp. 1 and Pr and Ac of one logger in Exp. 2 were considered outliers. In conclusion, both proximity loggers demonstrated high precision, specificity, and accuracy but low sensitivity in recording proximity among beef bulls. Therefore, these characteristics should be considered when deciding whether to use these devices or not.

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.

Forty Hereford cross calves (mean and SD of 47.9 ± 10.43 d old) were used to assess the efficacy of lidocaine administered immediately before surgical castration on physiological and behavioral indicators of pain and discomfort. Calves were assigned by age to one of two treatments: surgical castration following subcutaneous injection of 2.5 mL/100 kg body weight of meloxicam (Metacam 20 mg/mL, Boehringer Ingelhein, Burlington, ON, Canada) per kg body weight (MEX, n = 19); or the same treatment preceded 90 s before by a nerve block of the spermatic cord using 8 mL of buffered (1 mL:10 mL of 8.4% sodium bicarbonate USP, Hospira Inc., Lake Forest, IL, USA) lidocaine (4 mL per cord; 20 mg/mL, LIDO-2 with epinephrine, Rafter Products, Calgary, AB, Canada) (LID, n = 21). During the castration procedure, two observers scored how much pain each animal was experiencing (visual analog score, VAS), number of body shakes and leg kicks for each calf. Blood samples and exit scores were collected the day of castration and on d 7, and 14 to assess the neutrophil-to-lymphocyte ratio (N:L) and calf temperament, respectively. Hair samples were collected the day of castration and on d 14 to determine cortisol levels. Scrotal circumference, swelling, and healing scores were determined on d 7 and 14 to assess healing. An accelerometer (HOBO Pendant® G Data Logger, Onset, Cape Cod, MA) was placed on the left hind leg to measure lying behavior until d 6 after castration. Calves were video recorded for 1 hour after the castration procedure to observe behaviors indicative of pain and discomfort. Surveillance cameras were also used to assess the mobility of the calves when cow-calf pairs were moved from the holding pen to the pasture. The VAS, number of tail flicks and foot stamps were greater (P < 0.01) in MEX than in LID calves. During the first hour after castration, LID calves spent more time lying (P = 0.03) and less time standing (P = 0.01) than MEX calves. When moved from the holding pen, LID calves moved faster (P < 0.01) and closer to their dams (P < 0.05) than MEX calves. Hair cortisol was greater (P < 0.05) in LID than MEX calves on d 14. Results suggest that using lidocaine for local anesthesia immediately before surgical castration reduced behaviors indicative of pain and improved mobility post-castration.

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.