S. Marti

Effect of castration and slaughter age on performance, carcass, and meat quality traits of Holstein calves fed a high-concentrate diet

The aim of this study was to evaluate the effect of castration and slaughter age on performance and meat quality of Holstein bulls fed a high-concentrate diet. A total of 132 animals (116 ± 3.7 kg of BW and 97 ± 2.4 d of age) were randomly allocated in 6 pens using a 3 × 3 factorial arrangement of treatments. Three castration ages [bulls, animals castrated at 3 mo (CAS3), and animals castrated at 8 mo of age (CAS8)] and 3 slaughter ages (10, 12, and 14 mo of age) were evaluated. Feed intake was recorded daily using a computerized concentrate feeder, and BW was recorded every 14 d. The 9th to 11th rib section was removed at 24 h postmortem and dissected into lean, fat, and bone, and meat quality was evaluated on the LM. Castration, at 3 or 8 mo of age, reduced (P < 0.001) ADG and muscle pH and impaired (P < 0.01) feed efficiency. As slaughter age increased, concentrate consumption increased linearly (P < 0.001) and feed efficiency was reduced linearly (P < 0.001). Slaughter age also affected (P < 0.001) meat pH. Significant interactions between castration and slaughter ages were also observed in carcass conformation (P < 0.05), fatness (P < 0.001), percentage of subcutaneous fat (P < 0.01), carcass dressing percentage (P < 0.05), and intramuscular fat (P < 0.05) and tended to be significant in intermuscular fat (P = 0.09). In Holstein animals, castration age affects performance and meat pH regardless of slaughter age, and slaughter age affects performance and meat pH independently of castration. However, in Holstein animals, castration affects several characteristics related to fat deposition differently depending on slaughter age, such as carcass fat cover and intramuscular, intermuscular, and subcutaneous fat.

Effects of castration on eating pattern and physical activity of Holstein bulls fed high-concentrate rations under commercial conditions1

A total of 132 animals (initial BW = 220 ± 22 kg and age = 166 ± 0.4 d) were used to study the effect of castration on eating behavior and physical activity. Animals were randomly allocated to 6 pens with 2 pens for each of the 3 treatment groups: 44 intact bulls, 44 steers castrated (3 mo of age) before the study began, and 44 bulls castrated (CAS) at 8 mo of age (at d 69 of the study). The study finished when animals reached 292 d of age. Each pen held 22 animals, and had 1 computerized concentrate feeder (GEA WestfaliaSurge, Germany), 1 feed trough for straw, and 1 water source. Concentrate and straw were offered ad libitum. Animals were weighed every 14 d and eating pattern at which animals consumed concentrate was averaged for each 14-d period. A pedometer was placed on the left hind leg of 86 animals randomly distributed among treatments to estimate physical activity from d -5 to 10 relative to surgical castration (d 65 to 79 of study). The statistical model included initial BW as a covariate, treatment, period, and the interaction between treatment and time (14-d), as fixed effects, and pen and animal as random effects. For physical activity data, day was the repeated measure. The CAS animals exhibited reduced ADG and concentrate DMI (P < 0.001) during the first 2 wk after castration than bulls or steers. Eating behavior throughout the study differed among treatments. Meal size (1.3 ± 0.05 kg) and meal duration (12.4 ± 0.47 min) were greater (P < 0.001) in bulls during the 2 wk after castration than in steers (1.0 ± 0.05 kg and 9.7 ± 0.46 min, respectively) and CAS animals (0.8 ± 0.05 kg and 7.8 ± 0.47 min, respectively). In contrast, bulls visited the feeders less frequently (5.3 ± 0.34/d) during these 2 wk than did steers (6.7 ± 0.34/d) and CAS animals (7.7 ± 0.34/d). In addition, daily intake, meal size, and eating rate increased (P < 0.001) with time. Lying time in CAS animals was reduced (P < 0.001) for the 5 d after castration compared with bulls and steers. Bulls were more active (steps/h) than steers, and activity of recently castrated animals decreased (P < 0.001) for at least 10 d after castration. Although 2 wk after castration differences in eating pattern across treatments were observed, the long-term effects of castration and gender (bull vs. steer) on eating behavior were difficult to interpret. Castration effects on total feed intake and lying time are temporary, whereas castration has a lasting reduction on physical activity.

Effect of anti-gonadotropin-releasing factor vaccine and band castration on indicators of welfare in beef cattle

Angus crossbred bulls (n = 60; 257 ± 5.4 d of age; initial BW 358.8 ± 3.78 kg) were used to study the effect of a vaccine against gonadotropin-releasing factor (GnRF) and band castration on behavioral and physiological indicators of pain. Cattle were randomly assigned to 1 of 3 treatments: bulls, band-castrated calves without pain mitigation (castrated), and immune-vaccinated animals administered an anti-GnRF vaccine (vaccinated). All animals were fitted with a radio frequency ear tag so that individual animal feed intake and feeding behavior were recorded daily over the entire trial using an electronic feed bunk monitoring system. Two doses of anti-GnRF vaccine were administrated on d -35 and 0 and band castration was performed on d 0. Animal BW was recorded weekly starting on d -36 until d 56. Visual analog scores (VAS) were measured on d -36 -35, -1, and 0, and salivary cortisol concentration was measured at -30, 0, 30, 60, 120, and 270 min on d -35 and 0 after castration. Saliva and blood were obtained on d 1, 2, 5, and 7 and weekly until d 56 for determination of cortisol and complete blood cell count. Video data were collected for pain, sexual, and aggressive behavior daily the first week and once a week until d 56. Data were analyzed with a mixed-effect model with castration, time, and their interactions as main effects. Vaccinated calves had reduced ADG and intake (P < 0.05 and P < 0.001, respectively) during the first week after vaccination. Band-castrated calves had reduced ADG and intake (P < 0.001) until the end of the study. No differences in salivary cortisol and VAS were observed among groups at d -35 after the first vaccination and before band castration. However, on d 0, castrated cattle had greater cortisol concentrations and VAS (P < 0.05 and P < 0.01, respectively) than bulls and vaccinated animals. Complete blood cell count did not differ (P > 0.05) between treatments on d 0, 1, and 2. At d 56, vaccinated calves had greater (P < 0.05) final BW than band-castrated calves and both had less final BW than bulls. There was no indication that vaccination caused any physiological or behavioral changes indicative of pain. In contrast, band castration resulted in elevated cortisol scores and VAS indicative of a pain response and behavior related to pain (P < 0.001) until d 42 of the study. The present study demonstrates that anti-GnRF vaccine is a viable animal welfare-friendly alternative to traditional band castration in beef cattle under North American feedlot practices.

Behavior and inflammation of the rumen and cecum in Holstein bulls fed high-concentrate diets with different concentrate presentation forms with or without straw supplementation.

Twenty-four individually housed Holstein bulls (395 ± 7.3 kg BW and 252 ± 3.1 d age) were exposed to a 2 × 2 factorial design (meal vs. pellets; with vs. without straw) to evaluate the effect of concentrate form and provision of straw in finishing diets on behavior and expression of rumen and cecum epithelium genes related to inflammation and behavior. Concentrate and straw consumption were recorded monthly and behavior (self-grooming, social, oral nonnutritive, tongue rolling, eating, drinking, ruminating, and lying) was recorded every two weeks. Bulls were slaughtered after 64 d of exposure to treatments, lesions on the rumen and liver were assessed, and samples of the rumen and cecum were collected. Straw supplementation tended ( = 0.08) to increase concentrate intake (8.0 vs. 7.4 ± 0.26 kg/d), increased ( < 0.01) the proportion of time ruminating (9.4 vs. 3.1 ± 1.02%), and decreased ( < 0.01) the occurrence of oral nonnutritive behaviors (0.52 vs. 1.34 ± 0.123 times/15 min) relative to bulls deprived of straw. Provision of straw increased ruminal pH, but the magnitude of the change was greater when the concentrate was provided as meal compared with pellets (interaction, < 0.05). When straw was not supplemented, all rumen samples had papillae fusion, whereas only 16.7% of bulls fed pellets and straw had papillae fusions (interaction, < 0.05). Vacuole grading of the rumen papillae was less ( < 0.01) in bulls provided straw compared with bulls without straw. For the ruminal epithelium, straw provision tended to increase the relative expression ratio of (which stimulates peptide YY, PYY, and serotonin secretion; = 0.06) and α (which modulates immune reactions and behavior; = 0.09) and increased and (tight junction proteins; < 0.05), along with β and (proinflammatory cytokines; < 0.01) and ( < 0.01) in the rumen. Moreover, it also tended to increase the relative gene expression ratio of β (an antimicrobial peptide; = 0.10) and ( = 0.10). Bulls fed pellets had a decreased ruminal relative expression ratio of α ( < 0.05). Bulls without straw had increased ( < 0.05) the cecum relative expression ratio of β. In conclusion, the lack of straw supplementation in bulls fed high-concentrate diets modifies behavior and affects rumen macroscopic morphology and expression of epithelial genes that could be related to behavior and inflammation.

Effect of band and knife castration of beef calves on welfare indicators of pain at three relevant industry ages: I. Acute pain

Three experiments evaluated the effect of band and knife castration on acute pain for the first 7 d after the procedure on 1-wk-, 2-mo-, and 4-mo-old calves. All calves were blocked by age and weight and randomly assigned to 1 of 3 treatments: sham castration (control, CT), band castration (BA), and knife castration (KN). Experiment 1 evaluated 1-wk-old Angus bull calves ( = 34; 43.0 ± 6.61 kg BW), Exp. 2 evaluated 2-mo-old Angus bull calves ( = 34; 91.5 ± 11.93 kg BW), and Exp. 3 evaluated 4-mo-old Angus bull calves ( = 35; 157.6 ± 22.52 kg BW). For all experiments, physiological and behavioral parameters were collected before (d -1 and immediately before castration [T0]) and after (60 and 120 min and on d 7) castration to assess acute pain. Physiological measures included complete blood cell count, cortisol, substance P, and scrotal temperature. Behavioral measures consisted of a visual analog scale, stride length, and time and frequency budgets for walking, standing, lying, tail flicking, foot stamping, and head turning. Performance parameters included initial and final BW and ADG. In Exp. 1, tail flicking was greater ( = 0.02) in KN calves compared to BA calves 2 to 4 h after castration, although no differences were seen between BA and KN compared to CT calves. In Exp. 2, a treatment × time interaction ( = 0.02) was observed for cortisol, where KN calves had greater cortisol concentrations 120 min after castration compared to BA and CT calves; KN calves also lay down and ate less ( < 0.01; = 0.02) and stood and walked more ( < 0.01; = 0.05) compared to BA and CT calves 2 to 4 h after castration. In Exp. 3, a treatment × time interaction ( < 0.01) was observed for cortisol concentrations in which all treatments were different from one another at 60 and 120 min, with BA calves having the greatest concentrations, KN calves being intermediate, and CT having the lowest concentrations. Overall, KN and BA castrated calves presented physiological and behavioral changes associated with acute pain; however, 2-mo-old BA calves presented the fewest behavioral changes and no physiological changes associated with acute pain compared to CT calves.

Effect of dietary energy density and meal size on growth performance, eating pattern, and carcass and meat quality in Holstein steers fed high-concentrate diets

A total of 121 steers (162 ± 3.0 kg BW and 148 ± 2.7 d old) were used to study the effect of dietary energy density and meal size (limiting the amount of concentrate delivered at each feeder visit) on performance, hormones associated with the regulation of intake, and carcass and meat quality. Steers were allocated by BW to 6 pens. Each pen had the same BW mean and CV, and pens were randomly assigned to 3 treatments (2 pens/treatment): a concentrate of moderate energy density (3.23 Mcal ME/kg, 6.2% ether extract) fed for ad libitum intake with no control on meal size (CTR), a concentrate of high-energy density (3.43 Mcal ME/kg, 8.3% ether extract) fed for ad libitum intake with no control on meal size (HE), and the same high-energy concentrate offered for ad libitum intake but with meal size limited to a maximum concentrate delivery of 0.6 kg DM/visit (HELM). Body weight was recorded every 14 d; concentrate consumption and eating pattern were recorded daily. On d 163, blood samples were collected to determine serum concentrations of leptin, ghrelin, glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), glucose, and insulin. After slaughter (on d 166 to 170), the 9-10-11 rib section was removed to estimate separable bone, lean, and fat. Meat quality of LM was analyzed. Data were analyzed using a mixed-effects model with repeated measures. Steers in the HELM treatment had a lower (P < 0.01) final BW and ADG than CTR and HE steers. Concentrate intake was greater (P < 0.001) in CTR (6.6 ± 0.10 kg/d) than in HE steers (5.7 ± 0.10 kg/d), and HELM (5.2 ± 0.10 kg/d) consumed less concentrate than CTR and HE steers. However, HE and HELM steers were more (P < 0.01) efficient than CTR steers. The mean number of daily meals and eating rate were less (P < 0.05) for HELM than for HE or CTR. At d 163, serum concentrations of GLP-1, CCK, and insulin were lower (P < 0.05), and leptin (P = 0.10) and glucose (P = 0.08) concentrations tended to be lower for HELM than for CTR or HE. Carcass conformation and HCW were less (P < 0.05) for HELM than for CTR. Although differences among treatments were observed in carcass fat cover, intramuscular fat did not differ among treatments. Limiting the amount of feed delivery per feeder visit in steers fed high-energy (fat) diets affected eating pattern, reduced total energy consumption and performance, and modified hormones related to intake compared with CTR and HE, but no effect on rib fat distribution and meat quality was observed.

Effect of rest stop duration during long-distance transport on welfare indicators in recently weaned beef calves

Forty newly weaned beef calves (260 ± 32.6 kg) were transported 15 h in a livestock trailer (7.3 by 2.1 m) on 2 separate hauls 1 wk apart (20 calves/haul) to evaluate the effect of rest stop duration on indicators of calf welfare. Immediately following the 15-h journey, 15 calves/haul were randomly unloaded at a feedlot and randomly assigned to 1 of 3 rest stop treatments; calves without resting time (5 calves/haul) remained on the trailer and were used as the control group. Treatments included 0- (Control [CON]), 5- (RS5), 10- (RS10), or 15-h (RS15) rest periods in pens containing ad libitum access to water and long-stem hay. Following each rest period, calves were reloaded onto the same trailer and taken on another 5-h journey, before they were unloaded at the same feedlot, for a total transport event lasting 20 h. Control calves did not have access to feed or water until the end of the 20-h transit event. Behavioral measurements included bunk attendance (min/d) and standing and lying duration (min/d) recorded for 5 h after the 20-h transport event. Physiological measurements included saliva and hair cortisol, complete blood cell count, serum NEFA, haptoglobin, and substance P concentrations. All physiological measurements as well as BW were taken immediately prior to initial loading, at arrival at the feedlot after the 20-h event, and 48 h after the transport to the same feedlot. Hair cortisol was collected prior to the initial loading and 25 d after transportation. No differences ( = 0.78) in BW loss were observed among treatments after transportation. Standing time was greater ( < 0.001) in CON calves compared with RS5, RS10, and RS15 calves. Salivary cortisol was greater ( < 0.01) in CON and RS15 calves than in RS5 and RS10 calves at the end of the 20-h journey. Serum NEFA concentration was greater ( = 0.03) in RS5 and RS10 calves at arrival compared with CON and RS15 calves, but those differences were no longer observed ( = 0.49) 48 h after transportation. Concentration of substance P did not differ ( = 0.18) between treatments, and haptoglobin concentration tended to be greater ( = 0.07) in CON calves compared with the other treatments 48 h after arrival. Hair cortisol tended ( = 0.10) to be lower in RS5 calves compared with the other treatments. The results of this study indicate that rest stop periods ≥ 10 h did not prevent short- and long-term stress after transport in weaned calves.

Economic impacts of lameness in feedlot cattle

Abstract Lameness is an important health issue in feedlot cattle; however, there is a paucity of information regarding its economic impact. Decision tree models are excellent tools for assessing costs of disease such as the net return (net return = benefit – cost). Models were developed using expert opinion, literature and retrospective feedlot data provided by Vet-Agri Health Services (VAHS, Airdrie, Alberta, Canada) collected from 2005 to 2015 on individually treated cattle (n = 30,940) from 28 feedlots. The objective was to estimate net return of various lameness diagnoses and impacts of cattle type, season of treatment, and extreme high and low cattle prices. Cattle were diagnosed as lame according to the following categories: foot rot, foot rot in heavy cattle (BW > 363 kg at treatment), injury, lame with no visible swelling, and joint infection. Records consisted of arrival and treatment weight, cost of treatment, and cattle deaths. Records included cattle types classified as: fall calves (heifer and steer), winter calves (heifer and steer) and yearling cattle (heifer and steer). Lastly, variables ADG, days on feed (DOF), and Season (spring, summer, fall, and winter) were created. Models estimated net return using cattle slaughter prices for healthy cattle that reached a slaughter weight of 635 kg and for three possible outcomes for each diagnosis after final treatment: cattle that recovered after treatment and reached a slaughter weight of 635 kg; cattle that were removed before they reached slaughter weight; or cattle that died. Compared to undiagnosed cattle with 1.36 kg/d ADG, cattle diagnosed with foot rot and foot rot heavy cattle had the highest ADG until first treatment (1.14 and 1.57 kg/d, respectively) and differed significantly (P < 0.05) compared to cattle diagnosed with injuries (0.87 kg/d), lame with no visible swelling (0.64 kg/d), and joint infections (0.53 kg/d). Yearling steers had the most positive returns compared to all other cattle types. Cattle with lighter arrival weight had lower ADG and increased economic losses after treatment compared to heavier weighted cattle on arrival. Based on average slaughter prices over a 10-yr period for healthy cattle, return was

Use of pattern recognition techniques for early detection of morbidity in receiving feedlot cattle

690. Return after final treatment for cattle with foot rot was

Feeding behavior and ruminal pH of corn silage, barley grain, and corn dried distillers’ grain offered in a total mixed ration or in a free-choice diet to beef cattle

568, foot rot in heavy cattle was