Search Results (28)

Early diagnosis of heat load in beef cattle remains a challenge due to the limited understanding of behaviour-based indicators. This preliminary longitudinal study aimed to validate behavioural and physiological responses previously identified as heat load indicators. Black Angus steers were exposed to high environmental temperatures expected to cause heat load in the following sequence: an initial thermoneutral period, a hot period, and a recovery period. Changes in the positioning of key body parts, feeding behaviour, body maintenance, respiratory dynamics, and eye temperature were monitored. In the hot period, cattle increased their respiration rate, panting, and infrared eye temperature. Increased stepping by their left limbs suggested involvement of the right brain hemisphere in a stress response to high environmental temperatures. Cattle also held their heads more downward, ears backward, and their tail vertical, and reduced eating, grooming, and scratching during the hot period. Cattle responses to hot conditions were persistent in the recovery period, reflecting diagnostic relevance of the head, ear, and tail movements, stepping, especially by left limbs, and infrared eye temperature as non-invasive tools to identify heat load condition in cattle. The study reinforces our understanding of the specific behavioural and physiological responses to heat load condition, especially those involving left-limb stepping, ear and tail posture, and infrared eye temperature, are reliable indicators for identifying cattle experiencing high environmental temperature. Full article

This study evaluated the effects of including additional roughage and the timing of roughage addition on rumen temperature (T_RUM), rumen pH, dry matter intake as a percentage of live weight (DMILW), water consumption as a percentage of live weight (WILW) and average daily gain of grain-fed steers exposed to a simulated heat wave. A total of forty-eight Black Angus steers (539.53 ± 4.95 kg) were housed within climate control rooms for 21 days and exposed to a 5-day simulated heat wave. Steers were randomly allocated into four cohorts with 12 steers/cohort, and then allocated to one of three dietary treatments: Treatment 1 (T1) were fed a finisher diet for the 21 days; Treatment 2 (T2) transitioned from the finisher diet to a heat load diet on d 9 and fed the heat load diet until d 14; and Treatment 3 (T3) transitioned from the finisher diet to the heat load diet on d 7 and fed the heat load diet until d 14. On d 15, T2 and T3 transitioned back to the finisher diet. The study was categorised into five phases consisting of (i) Phase I, d 0–6 (Temperature Humidity Index, THI 65 to 78); (ii) Phase II, d 7–8 (THI 65 to 78); (iii) Phase III, d 9–11 (THI 83 to 90); (iv) Phase IV, d 12–13 (THI 78 to 85); and (v) Phase V, d 14–20 (THI 65 to 78). During the heat wave challenge in Phase III, all Treatments exhibited lower DMILW (p < 0.0001), greater T_RUM and rumen pH (p < 0.0001), lower ranges in T_RUM and rumen pH (p ≤ 0.0005) and altered diurnal T_RUM and rumen pH rhythms. Average daily gain was not influenced by Treatments (p ≥ 0.98). Overall, these results suggest that nutritional management remains an important consideration to reduce the impact of hot climatic conditions on the rumen environment during heat wave and post-heat wave conditions. Full article

Emerging research evokes selection for various plant secondary compounds as a potential driver of ruminant diet selection, through animals’ evident ability to rectify deficiencies and even self-medicate. This idea was assessed by comparing physiological responses to vaccination challenges of animals fed diets of differing phytochemical composition. In the first of three separate trials, goats were placed in individual pens and fed one of three treatments in a completely randomized design. Treatments in Trial 1 consisted of redberry juniper (50 g) and shin oak (50 g). In Trial 2, goats were fed rations containing grape and blueberry pomace at an inclusion rate of 20%. In Trial 3, black Angus heifers were fed rations containing grape and blueberry pomace at an as-fed inclusion rate of 6%. Average daily gain, intake, and blood chemistry were assessed following vaccination health challenges. In Trial 1, goats fed shin oak had higher (p < 0.05) blood globulins. Trial 2 revealed no treatment group differences in average daily gain (ADG), intake, or blood parameters evaluated. In Trial 3, no difference occurred in blood parameters; however, intake following inoculation was significantly greater (p < 0.05) for heifers with grape/blueberry pomace included in their rations. In conclusion, phytochemicals, specifically condensed tannins, may have the ability to enhance immune response in ruminants, but further research is required, and these effects likely depend upon the source, structure, and dose of tannins or parent plant materials offered. Full article

The use of non-invasive technologies is among the most accurate methods for assessing meat quality parameters. Beef tenderness and palatability are strongly influenced by the amount of intramuscular fat, commonly referred to as marbling. Marbling is widely used in breeding programs to select animals with superior meat quality. In this study, we analyzed 236 Angus bulls and 22 Angus heifers from various farms in Lithuania, all aged 450 ± 112 days. Ultrasound examinations were performed using a linear transducer with a silicone standoff to evaluate the loin eye area. Key meat quality indicators, such as fat thickness, loin area and thickness, and intramuscular fat, were found to increase with the weight of bulls, ranging from 365 ± 12.70 kg to 825.57 ± 11.75 kg (p < 0.001), and heifers, ranging from 273 ± 20.71 kg to 767 ± 41.01 kg (p < 0.001). The highest intramuscular fat values were observed at 7.50 ± 0.75% (p < 0.05) to 6.9 ± 1.36% (p < 0.1) in bulls weighing 431.33–825.57 kg and 7.98 ± 0.28% (p < 0.001) in heifers weighing 603 kg. These findings demonstrate the feasibility of selecting Angus cattle for improved meat quality traits across different weight categories. Full article

This study evaluated the effects of a botanical supplement (a formulated proprietary blend of turmeric, capsicum, and black pepper oleoresin in a fat carrier; PHYT), fed pre- and post-calving, on colostrum and milk yield and the quality, passive transfer of immunity, and performance of cow–calf pairs. Twenty-three (BW = 532 ± 9.13 kg; age 36 mo) crossbred Angus cows were randomly assigned to three treatment groups: (1) not supplemented (CON, n = 7); (2) supplemented with 250 mg/head/day (PHYT250, n = 8); or (3) supplemented with 500 mg/head/day (PHYT500, n = 8) of the botanical supplement. The cows were individually fed the supplement from 30 days (±6 days) pre-calving to 60 days post-calving. Colostrum was collected on d 0 (pre-suckling), and d 1, d 2, and d 3 post-calving. The total milk from all quarters was collected 45 and 90 d post-calving and at weaning. Colostrum and milk volumes were recorded, and samples were analyzed for percentages of fat, protein, milk urea nitrogen, other solids, and lactose. Colostrum samples were analyzed for concentrations of IgG, IgA, and IgM, and milk samples were analyzed for IgG concentration using radial immunodiffusion. Blood samples were collected from dams and calves, and serum was analyzed for concentrations of IgG (cows and calves) and IgA (calves). Cow and calf BW were measured periodically until weaning. Supplementation with PHYT linearly increased fat in colostrum (CON = 3.29, PHIT250 = 4.23, and PHYT500 = 4.17 ± 0.77%; p = 0.05) and IgA in calf serum (96.91, 151.69, and 183.42 ± 29.78 mg/dL for CON, PHYT250, and PHYT500, respectively; p = 0.04) and tended to linearly increase concentrations of fat in milk (CON = 3.84, PHYT250 = 4.05, and PHYT500 = 4.71 ± 1.04%; p = 0.07), IgG in calf serum (2082.31; 2196.29; and 2577.78 ± 213.08 mg/dL for CON, PHYT250, and PHYT500, respectively; p = 0.09), and IgM in colostrum (CON = 179.04; PHYT250 = 170.79; PHYT500 = 218.30 ± 16.08 mg/dL; p = 0.09). A quadratic response was observed for calf ADG (p = 0.03), where CON (0.99 ± 0.03 kg/d) was less than PHYT250 (1.10 ± 0.03 kg/d), and intermediate values were observed for PHYT500 (1.01 ± 0.03 kg/d). In summary, supplementation with PHYT led to a linear increase in colostrum fat and IgA levels in calf serum. Additionally, supplementation tended to linearly elevate fat concentrations in milk, IgG levels in calf serum, and IgM levels in colostrum. Our results suggest that supplementing beef cows in late gestation and early lactation with 250 or 500 mg/head/d of PHYT improves colostrum quality and calf health and performance. Further investigation is needed to determine both the biological significance and the economic benefits of botanical additives in beef production. Full article

The extent of endocrine changes in response to various levels of heat stress and subsequent recovery is not well understood. Two cohorts of 12 Black Angus steers were housed in climate-controlled rooms (CCR) and subjected to three thermal periods: PreChallenge (5 d), Challenge (7 d) and Recovery (5 d). PreChallenge and Recovery provided thermoneutral conditions. The Challenge simulated a strong heatwave. Finally, the steers were maintained in outdoor pens for 38 d. Rumen temperature (RumT), respiration rate (RR) and panting score (PS) were intensively measured in the CCR. Dry matter intake (DMI) was determined daily. The steers were bled most days, and a rectal temperature (RecT) was taken also. Plasma concentrations of TSH, prolactin, T3, T4, insulin, leptin and adiponectin were determined. During the Challenge, RumT, RecT, RR and PS rose; DMI was reduced. Plasma T3, T4 and adiponectin levels fell also. In Recovery, RumT, RecT, RR and PS fell below the PreChallenge mean. DMI partially recovered. T4 and adiponectin levels remained suppressed alongside lowered insulin. There were linear relationships between T3 concentration and THI, and T3 and T4 levels and DMI only. We highlight comparisons with previously reported metabolic hormone responses of grain-fed Black Angus steers to a moderate-heat-load challenge. Full article

This study investigated the genetic parameters for serum IGF-I concentrations and growth traits in beef cattle. A divergent selection experiment for serum IGF-I concentration was initiated in 1989. One hundred spring-calving (50 high line and 50 low line) and 100 fall-calving (50 high line and 50 low line) black Angus cows with unknown IGF-I concentrations were randomly assigned to the two divergent selection lines. For the 2009 through 2017 breeding seasons, the selection criterion in the two lines was changed from serum IGF-I concentration to high vs. low maintenance energy expected progeny differences (ME EPDs). The number of records available for analysis varied from 2056 for IGF-I concentration on day 42 of the postweaning performance test to 2988 for birth weight, with the exception that only 617 records were available for IGF-I concentration at weaning. (Co)variance components were estimated for direct and maternal additive genetic effects using an animal model and multiple-trait, derivative-free, restricted maximum likelihood (MTDFREML) computer programs. Direct heritability estimates for serum IGF-I concentrations ranged from 0.34 ± 0.07 to 0.46 ± 0.07, whereas direct heritability estimates for weight traits ranged from 0.32 ± 0.05 to 0.39 ± 0.07. Maternal genetic effects on IGF-I were low, with estimates ranging from 0.02 ± 0.11 to 0.17 ± 0.05, and were similarly low for weight traits. Maternal permanent environmental effects were negligible for IGF-I but were larger for weight traits, especially for weaning weight (0.22 ± 0.04). Direct maternal correlations for postweaning IGF-I concentrations were approximately −0.90. The genetic correlations of IGF-I with weight traits were generally low, with negative correlations observed for birth weight and small positive correlations for the other weight traits. Environmental and phenotypic correlations between IGF-I concentrations and growth traits were generally small, indicating circulating IGF-I has a modest impact on growth traits in beef cattle. Full article

Cattle are increasingly exposed to hot temperatures as a result of climate change, and a better understanding of behavioural responses could be beneficial for the diagnosis of heat loads. The changes in the positioning of key body parts, feeding behaviour, body maintenance, and respiratory dynamics were assessed in 24 Black Angus steers individually exposed to hot conditions and fed a finisher diet based on cereal grain or a substituted diet (8% of the grain replaced by an isoenergetic amount of lucerne hay). Increased respiration rate during the heat load period, compared to the recovery period, was associated with increased stepping, especially by left limbs. Cattle also reduced eating, grooming, and scratching during the heat load period. The lowered head, backward ear, vertical or raised tail, and increased respiration rate and panting persisted in cattle during the heat load period. Cattle on the cereal grain diet stood for longer and were more likely to hold their ears backward and tail vertical than those on the substituted diet. We conclude that these behaviours could be used to detect animals that are most affected and that changing from a cereal-based diet to a substituted diet containing a higher amount of fibre, such as lucerne hay, can reduce hyperthermic behavioural responses to a heat load. Full article

In response to the increasing global demand for sustainable beef production, this review of the literature was undertaken to explore the possibility of using the progeny of cows in the pasture-based New Zealand dairy production system that are mainly of the Holstein–Friesian, Jersey, and Holstein–Friesian × Jersey-cross breeds, to produce beef that meets the standards demanded by the Certified Angus Beef^® (CAB) standard. CAB is a United States of America (USA) benchmark for beef quality. Traditionally, the offspring of dairy breeds have not been suitable for producing high-quality beef due to their genetic makeup and physical characteristics. However, in the USA, breeding programmes have used genetic strategies to boost muscle meat yield in terminal-sire breeds like the Lim-Flex^® and NuEra Genetics^® T14 cattle lines. In these lines, selection has focused on enhancing muscling and other Angus traits, including ensuring the cattle are homozygous polled and black-coloured. The overall aim has been to alter the phenotypic characteristics of the offspring of dairy cows by terminal-sire crosses, so they resemble the phenotype of purebred Angus cattle and meet the CAB standard. The approach can involve using different alleles of the myostatin gene (MSTN) carried by the terminal Angus sires to increase carcass value from the dairy cow-derived male progeny (including the MSTN c.821(del11) allele or the myostatin protein p.F94L leucine-containing allele) to increase meat yield and eating characteristics. It is concluded that a targeted selection and mating strategy could provide another source of high-quality beef production, and one that also meets societal demands for better animal welfare and increased sustainability. Full article

Essential oils are natural feed additives that improve animal health and enhance their performance. This study investigated the effects of the rumen infusion of five essential oil blends (EOBs) on greenhouse gas (GHG) emissions, rumen fermentation parameters, and rumen metabolome and metabolic pathways in Black Angus cows. Using a 6 × 6 Latin Square experimental design, a 90-day study was conducted with six cattle. A daily dosage of 4 mL of EOBs was administered during each infusion. Volcano plot analyses between the control (CON) and each of the EOBs (EOB1, EOB2, EOB3, EOB4, and EOB5) revealed several differentially abundant (p ≤ 0.05; absolute fold change ≥1.5) metabolites. The EOB5 treatment exhibited the most significant impact, with 26 differentially abundant metabolites, including elevated valine and reduced gallic acid. Volatile fatty acids (VFAs), including valerate, isobutyrate, and isovalerate, were significantly increased (p < 0.05). GHG emissions were not significantly affected, but a numerical decrease was observed in the animals infused with the EOB5 treatment. Ammonia nitrogen concentrations remained within the suitable range for rumen microbes’ growth, indicating a normal internal environment for microbial crude protein synthesis. In conclusion, the study has demonstrated that the direct infusion of EOBs significantly improved the generation of VFAs and impacted the energy production, protein synthesis, and microbial activity of the animals. Full article

As the beef industry moves towards efficient animal production to improve sustainability in agriculture, new production and management approaches are emerging. Among the many facets of the beef industry, cow–calf operations have the most opportunity for efficiency improvement, including improvements in fertility. This project accounts for measures and methods of (1) twinning reproductive technologies and (2) twin calf perinatal care and pre-weaning rearing. The overall objective was to produce twin calves using two reproductive technologies—embryo transfer and artificial insemination. The subobjectives were to determine accuracy of twin pregnancies embryo/fetal losses using ultrasonography, evaluate parturition and dystocia, and determine the effects of different twin-raising methods on neonatal behavior and growth. A fixed-time artificial insemination (FTAI) protocol was applied to 77 multiparous Angus-cross cows from a commercial beef herd in northcentral South Dakota during the summer of 2019. Cows were assigned to two different treatments groups: only artificially inseminated (AI) or received an embryo transfer following artificial insemination (ET + AI). They were estrous-synchronized, artificially inseminated (AI) with black Angus semen at day 0, and received and embryo transfer (ET) at day 7. Ultrasound examination detected 56% pregnancy risk for both groups, with sensitivity, specificity, and accuracy of 75%, 100%, and 90.5%, respectively, for bilateral twin detection. Calves were born during spring 2020. Twin calves (n = 34) and singleton calves (n = 11) were assigned to one of three raising methods: (1) twin born and twin raised (TT; n = 16), (2) twin born and single raised (TS; n = 18), and (3) single born and single raised (S; n = 11). Neonatal nursing behavior and birth weights were recorded, and adjusted day 200 and day 280 were calculated measures of vitality and growth. Blood samples were collected at age 24 h for colostrum intake measures (total serum protein, IgG1, and IgM). Twin calves were born 20% (p < 0.05) lighter in body weight than singletons; however, weights did not differ at day 280 between TT and S calves. TS calves had the shortest average latency to stand, but immunoglobulin concentrations did not differ among treatments. At weaning, cows that had birthed and raised twins produced more kilograms of live weight per pregnancy than cows birthing and raising singletons. Using ET + AI proved to increase twinning rate, and growth was maintained when raising both twins with their dam. Full article

Movements in cattle after captive bolt stunning cause problems in the slaughter process and lead to uncertainties in assessing stunning effectiveness. The objective of this study was to categorize and quantify these movements and determine animal- and process-related impact factors, as well as connections to stunning effectiveness and shooting position. In total 2911 cows, heifers, and bulls (dairy, beef, and crossbreeds) were examined (mean age 3.02 years). Movements from landing until at least four minutes after sticking were recorded by action cams (Apeman^® A100). Nine movement categories were defined (“kicking hind limb”, “twitching”, “bending and stretching hind limb”, “lifting and bending forelimb”, “body arching laterally”, “body arching ventrally”, and “arching backwards”). According to the movement severity, a score was assigned to each category. The scores were summed, either for certain process intervals, e.g., LANDING (ejection from the stunning box), HOISTING, or STICKING, or for the total time between LANDING and end of the FOURTH MINUTE OF BLEEDING (sum score). Statistical analysis (ANOVA) was performed on the scores. Only 6.6% of cattle showed no movement. Most movements occurred during STICKING and FIRST MINUTE OF BLEEDING, occurring rarely up to 8 min after sticking. While cows moved most at LANDING, bulls and heifers moved more if all process intervals were considered. The sum score was highest in German Angus, Charolais, and Limousin and lowest in Brown Swiss and Simmental. The score at LANDING was highest in German Angus and Black Holstein. The use of pneumatic stunners and an increase in bolt-exit length significantly reduced movements. No impact of stunning effectiveness on movements was found, but only 19 cattle showed reduced effectiveness. Full article

The myokines interleukin 6 (IL-6), interleukin 15 (IL-15), myonectin (CTRP15), fibronectin type III domain containing protein 5/irisin (FNDC5), and brain-derived neurotrophic factor (BDNF) are associated with skeletal muscle cell proliferation, differentiation, and muscle hypertrophy in biomedical model species. This study evaluated whether these myokines are produced by cultured bovine satellite cells (BSCs) harvested from 3- and 11-month-old commercial black Angus steers and if the expression and secretion of these targets change across 0, 12, 24, and 48 h in vitro. IL-6, IL-15, FNDC5, and BDNF expression were greater (p ≤ 0.05) in the differentiated vs. undifferentiated BSCs at 0, 12, 24, and 48 h. CTRP15 expression was greater (p ≤ 0.03) in the undifferentiated vs. differentiated BSCs at 24 and 48 h. IL-6 and CTRP15 protein from culture media were greater (p ≤ 0.04) in undifferentiated vs. differentiated BSCs at 0, 12, 24, and 48 h. BDNF protein was greater in the media of differentiated vs. undifferentiated BSCs at 0, 12, 24, and 48 h. IL-6, 1L-15, FNDC5, and BDNF are expressed in association with BSC differentiation, and CTRP15 appears to be expressed in association with BSC proliferation. This study also confirms IL-6, IL-15, CTRP15, and BDNF proteins present in media collected from primary cultures of BSCs. Full article

Two randomized complete block design experiments evaluated the influence that varying degrees of ingredient inclusion accuracy in a finishing diet have on growth performance and carcass traits. Treatments included (1) normal inclusion tolerance with a 0.454 kg tolerance for all ingredients (CON) or (2) variable inclusion tolerance where each ingredient was randomly increased or decreased but the targeted as-fed quantity for the daily delivery was met (VAR). In Experiment. 1, black Angus heifers (n = 60; initial shrunk BW = 460 ± 26.2 kg) were used in a 112 d experiment. Ten pens in total (5 pens/treatment, 6 heifers/pen) were used. The targeted diet (DM basis) consisted of high-moisture ear corn (75%), dried distiller’s grains (20%), and a liquid supplement (5%). As-fed inclusion rates for DDGS and LS varied from formulated targets by −20, −15, −10, −5, 0, +5, +10, +15 or +20%. The HMEC inclusion was adjusted so that the targeted as-fed amount of the diet was delivered daily. Treatment did not alter ADG, DMI, G:F, HCW, dressing percentage, rib-eye area, rib fat, USDA marbling score, KPH, yield grade, retail yield, empty body fat, or body weight at 28% estimated EBF, nor liver abscess prevalence or severity (p ≥ 0.15). In Exp. 2, Charolais–Angus cross steers (n = 128; initial shrunk BW = 505 ± 32.1 kg) were used in a 94 d experiment. Steers were assigned to pens (8 pens/treatment; 8 steers/pen) and one of the two management strategies used in Exp. 1 was employed. Ractopamine HCl was fed (300 mg per head daily) during the final 28 d. Diets consisted of (DM basis) dry-rolled corn (63%), dried distiller’s grains plus solubles (15%), liquid supplement (5%), grass hay (7%), and corn silage (10%). Ingredient inclusions were randomized in the same manner as Exp. 1, except LS inclusion was held constant. Corn silage inclusion was adjusted so that the targeted as-fed amount of the diet was delivered each day. Steers from VAR had increased (p = 0.01) DMI, but similar (p = 0.75) ADG resulting in reduced (p ≤ 0.02) G:F and growth-performance-predicted Net Energy for maintenance and gain. Treatment did not influence (p ≥ 0.38) HCW, dressing percentage, rib-eye area, rib fat, KPH, yield grade, retail yield, empty body fat, or body weight at 28% estimated EBF. A tendency for an increased USDA marbling score (p = 0.08) was noted in VAR. Under the conditions of this experiment, randomly altering ingredient proportions can impact growth performance and efficiency measures depending upon the type of finishing diet fed. Full article

The growing interest in improving rumen fermentation and mitigating methane emissions necessitates the use of essential oil blends (EOB) and fumaric acid (FA). This study evaluated the synergistic effect of four EOB with or without FA supplementation on in vitro dry matter digestibility, greenhouse gas emission, and total volatile fatty acid production using inoculum from three rumen-cannulated Black Angus beef cows. The study was arranged in a 4 × 2 + 1 factorial design to evaluate the effects of the four EOB and two FA levels on a total mixed ration (TMR). The EOB dosage was 100 µL while FA was added at 3% of total mixed ration. The EOB × FA interaction (p < 0.05) influenced the dry matter, neutral detergent fiber, and hemicellulose degradabilities. All the EOB and FA (EFA) treatments decreased (p < 0.001) the dry matter degradability compared to the control (TMR substrate only). The EFA4 treatment reduced the neutral detergent fiber and hemicellulose degradabilities compared to the control. The ruminal pH was influenced (p < 0.001) by both the EOB and FA inclusion, and the EOB × FA interaction was significant. The microbial mass was higher (p < 0.001) in the EFA1, EFA4, and EOB4 compared to the control and the EOB3 treatments. The EFA1 and EOB1 produced less (p < 0.001) gas than the control by 29.1 and 32.1%, respectively. Compared with the control, the EFA1 and EOB1 treatments decreased (p < 0.001) methane gas by 90.8% and 86.4%, respectively, while the carbon dioxide was reduced (p = 0.004) by 65.7 and 57.9%, respectively. The EOB × FA interaction was significant (p < 0.001) for the total and individual volatile fatty acid concentrations. The inclusion of FA increased the propionate concentration by 9.5% and decreased (p = 0.02) the acetate concentration by 4%. In summary, the synergistic effect of the EOB and FA offers an effective way to reduce greenhouse gas emission and enhance total volatile fatty acids. Full article