Performance Of Cattle Research Articles

396 Effects of allocation timing on cattle performance and forage utilization when swath grazing a sorghum-sudangrass hybrid in eastern Nebraska

Abstract Swath, or windrow, grazing is the process of cutting hay, leaving it in windrows, and allowing cattle to graze these windrows in the winter. This grazing system reduces winter feeding costs by mitigating the need to bale and transport hay, while having the potential for increased utilization compared with grazing the forage standing. This study aimed to determine the effect of varying allocation timing on cattle performance and forage utilization. A sorghum-sudangrass hybrid (Sorghum× drummondii) was planted in June 2023, cut in early November, and grazed from mid-November 2023 to mid-January 2024. A 16-ha field was divided based on seeding rate with one-half seeded at the recommended rate of 39.2 kg/ha (REC) and one-half with a double rate of 78.4 kg/ha (DOU). The field was subdivided into a total of 8 paddocks (4 per seeding rate) with either 10 (n = 4) or 11 (n = 4) windrows. Forage was cut and windrows were gathered from a 4.57 m width in the field. Prior to grazing, a 0.30 m length of three swaths in each paddock was sampled to determine initial forage mass. A total of 60 steers [initial body weight (BW) = 240 ± 8.3 kg] were stratified by BW and assigned to one of 8 paddocks (n = 7 or 8 calves) to result in equal BW per swathed area. Allocations were offered in full once-per week (1X) or, one-half of the total forage was allocated twice weekly (2X). Post-graze samples were collected to estimate utilization and allocation amount was adjusted as needed based on visual appraisal of post grazing biomass. Cattle were pulled from the field due to snow cover after a 64-d grazing period. The area grazed was used to calculate the animal unit months/ha (AUM) achieved for each paddock. Pre-grazing forage mass did not differ between allocation timing (P = 0.89) or among seeding rates (P = 0.10; REC = 6,720 ± 545 kg/ha, DOU = 8,534.0 ± 545 kg/ha). There was an allocation timing by seeding rate interaction (P < 0.01) for forage offered with 1X (10.62 kgּ steer-1ּ d-1) being offered more (P < 0.01) than 2X (8.43 kg/steer/d) within REC, but no difference (P = 0.31) in forage offered due to allocation within DOU (8.31 kgּ steer-1ּ d-1). However, post grazing biomass (P = 0.35) and utilization (59 ± 8%) were not affected by allocation timing (P = 0.48). Average daily gain (ADG) also did not differ (P = 0.93) due to allocation timing (0.20 ± 0.07 kg). Most notably, there was a significant allocation effect (P = 0.05) on AUM/ha with 1X (14.51 ± 1.00) being lesser than 2X (16.82 ± 1.00). However, there was no significant difference (P = 0.30) in forage disappearance (291 ± 61 kg/AUM) due to allocation timing. This indicates that more frequent allocations can lead to increased carrying capacity. Increasing the frequency of allocation is a simple management practice producers can implement when swath grazing sorghum-sudangrass to increase carrying capacity.

399 Effect of feeding palm oil products on finishing cattle performance, carcass characteristics, and methane production

Abstract The objectives of this experiment were to evaluate feeding palm oil products on feedlot cattle performance and methane production. Steers (n = 320; 380 ± 14.5 kg) were allocated to 40 pens in a randomized block design and assigned to 1 of 5 treatments consisting of different sources of supplemental fat: 1) No Oil; negative control containing 0.0% supplemental fat, 2) Corn Oil; positive control containing 4.0% supplemental corn oil, 3) Whole Palm; 4.0% supplemental whole palm oil, 4) Olein; 4.0% supplemental palm olein oil, or 5) Stearin; 4.0% supplemental palm stearin oil. Cattle consuming Corn Oil, Olein and Stearin all had greater (P = 0.04) final body weight (BW) and hot carcass weight (HCW) than cattle consuming no oil but were not different (P > 0.11) from each other or from Whole Palm, which was intermediate. Dry matter intake (DMI) of cattle consuming No Oil, Whole Palm and Stearin oil was not different from each other; however, cattle fed Corn Oil had greater intake than Whole Palm (P = 0.03). Corn Oil, Olein, and Stearin all had greater average daily gain (ADG) than cattle consuming No Oil (P = 0.04) but were not different (P > 0.12) from Whole Palm. Adding fat improved feed efficiency (gain to feed; G:F) as all diets including added fat had greater (P < 0.01) G:F than No Oil. Marbling scores were greater (P = 0.01) for Olein and Stearin than Corn and Whole Palm. There were no differences in backfat, ribeye area or liver abscess rate among any treatments (P > 0.74). Gas emissions were evaluated for only the No Oil and Whole Palm treatments. Total methane and methane produced per pound of dry matter intake was less for cattle consuming Whole Palm than No Oil by 14.8% (P < 0.04) while cattle were in the methane chamber. Methane produced per kilogram of ADG for Whole Palm was also reduced (P < 0.01) by 21.4% compared with No Oil. The results of this study indicate feeding palm oil products as a source of supplemental fat in finishing diets increases final BW, ADG, and HCW compared with feeding no supplemental fat, but had minimal impact on DMI resulting in an improvement in G:F. Adding supplemental fat reduced methane emissions in cattle when feeding Whole Palm compared with No Oil. The value of palm oil products in feedlot finishing diets is comparable with feeding corn oil.

130 Meta-analysis of the impact of Quebracho and Chestnut tannin extract supplementation on the growth performance in growing and finishing beef cattle

Abstract Integrating tannin extracts (TE) into the diet of growing and finishing beef cattle has shown promise in optimizing protein utilization while potentially mitigating methane emissions. Despite these potential benefits, there is a notable gap in a comprehensive analysis of the influence of TE on growth rate. This study addressed this gap by collecting data on the supplementation of a blend of condensed (from Schinopsis spp.) and hydrolyzable (from Castanea spp.) tannins, which has about 70% total tannins, and its impact on critical metrics, such as average daily gain (ADG, kg/d), dry matter intake (DMI, kg/d), and feed efficiency ratio (FER, g/kg). Our objective was to conduct meta-regression analyses to understand better the nuanced effects of condensed tannin supplementation on the overall performance of beef cattle during the critical stages of growth and finishing. The dataset was constructed by collecting published studies that reported in vivo experimental data on growing and finishing beef cattle supplemented with different levels of TE. It contained 132 observations from 35 publications. The meta-analysis was conducted by linear regression with a mixed-effects model fitted by the restricted maximum likelihood method using the nlme package of R software (ver. 4.3.1). Studies were assumed as random variables, and their interaction with the intercept and slope were included in the regression. The number of animals per treatment was used as a study-specific weight. Studies accounted for 32%, 35%, or 27% of the total variance when regressing ADG, DMI, or FER, respectively, on TE (% DM). After adjusting for random effects, the ADG increased (P < 0.001) with increasing levels of dietary TE (P < 0.001): 1.344 (± 0.0071) + 0.240 (±0.0298) × TE (n = 99, r2 = 0.40). It was observed that as the dietary TE level increased, its impact on the ADG tended to decrease from 0.33 kgּ d-1ּ % TE-1 when fed up to 0.5% TE to 0.24 kgּ d-1ּ % TE-1 when fed up to 1.5% TE, suggesting a possible nonlinear relationship between these two variables. Similarly, DMI decreased slightly (P < 0.001) at 0.61 kg/d/% TE, but with a lower precision (n = 115, r2 = 0.14). Consequently, FER increased (P < 0.001) at 17 kgּ d-1ּ % TE-1 (n = 93, r2 = 0.34). Initial findings suggest that incorporating TE into the diet of growing and finishing cattle, up to a concentration of 0.5% DM, positively influences the growth rate and enhances FER while minimally affecting DMI. Subsequent research endeavors should delve into a more intricate examination of optimal TE inclusion levels and explore additional performance indicators for a comprehensive understanding of its impact.

360 Effect of the administration of a protected source of calcium gluconate on growth, feed efficiency, nutrient digestibility, and health in beef cattle

Abstract The gastrointestinal tract has a central role in production efficiency due to its involvement in the digestive function as well as in immunological, nervous, and metabolic functions. In ruminants, a great deal of attention is placed on ruminal functionality and safety. However, it is now recognized that the hindgut is involved in the onset of some metabolic issues, normally associated with ruminal imbalances, as well as in the digestion efficiency. Thus, the application of nutritional strategies that target the hindgut are gaining interest in cattle nutrition. The study evaluated the effects of a protected source of calcium gluconate on performance, digestibility, and health in beef cattle. Charolaise bulls (n = 241) were randomly divided into two groups: i) Control (n = 120) basal diets + 10g/head/day of a placebo of wheat bran; ii) Treatment (n = 121) basal diets + 10 g·bull⁻¹·d⁻¹of a protected source of calcium gluconate (Lactibute, Selko Trouw Nutrition). The population was further divided into two subgroups: i) “Overall population” (n = 201) housed in pens of 7to 8 animals each; ii) “Beefmonitor population” (n = 40). The latter was housed in two pens (Control and Treatment) with 20 animals each equipped with two automatic scales for BW located at the drinkers, to evaluate the daily growth trends. Growth performance, feed intake (FI), feed conversion ratio (FCR), were evaluated with specific approaches in the two populations. The incidence of diseases was evaluated equally in the two populations. The apparent total tract digestibility (aTTD) was evaluated on 10 representative pens per group using a portable near-infrared system that compares the composition of the diets and the correlated feces. All the data were analyzed statistically using the SAS software and applying specific models. The average daily gain (ADG) was improved by the Treatment (+40 and +43 g·bull⁻¹·d⁻¹compared with the Control group, in the “Overall” and “Beefmonitor” populations; Table 1 and Figure 1; P = 0.0084 and < 0.0001, respectively), and the final BW were also heavier (706.82 and 705.83 vs 699.75 and 697.33 kg in the “Overall” and “Beefmonitor” populations; P = 0.0084 and 0.037, respectively). The treatment improved both, FCR (6.90 and 7.03 vs 7.51 and 7.28 in the “Overall” and “Beefmonitor” populations; P = 0.0008 and < 0.0001 respectively; Table 1 and Figure 1) and the aTTDs of starch (97.05 vs 95.71%; P < 0.0001), cellulose (57.91 vs 52.95%; P < 0.0001) and NDF (52.02 vs 50.02%; P = 0.020). The incidence of lameness was reduced in the Treatment group (0.99 vs 7%; P = 0.0282). Including protected sources of calcium gluconate can be functional to improve production efficiency and animal health, as a consequence of its proactive role on intestinal health, functionality and epithelial integrity.

260 Industrial hemp (Cannabis sativa) supplementation improved plasma antioxidant enzymes and stress hormones in beef cattle

Abstract Industrial hemp is a rich source of antioxidants due to its high CBD but there is little information known about its impact on plasma antioxidant enzyme activity and stress hormone in beef cattle. The objective of this study was to determine the effect of industrial hemp supplementation on plasma antioxidant enzymes and stress hormone of Angus cattle. Black Angus heifers (n = 20) were completely randomized into either control (CON: n = 10, receiving 0 g of hemp) or hemp (HEMP: n = 10, receiving 30 g of hemp in 200 g of commercial concentrate) in a trial that lasted for 6 wk. Each group was replicated twice. Hay and water were offered ad libitum, experimental diets were offered o700 h daily. Blood samples were collected on d 0, 7, 14, 21, 28, 35 of the experiment for enzyme-linked immunosorbent assay to determine enzyme activity using standard kits. Data were analyzed using GLIMMIX procedure for repeated measure in SAS 9.4 with Compound symmetry as covariance structure while means were separated with Tukey at 5% alpha. There was significant (P < 0.05) difference in cortisol with HEMP group having 97.54 ng/mL and 122.23 ng/mL for CON. There was treatment x time interaction in total antioxidant capacity (TAOC) and malondialdehyde, TAOC range was 7.26 to 13.95 U/mL in HEMP group and 7.56 to 11.80 U/mL in CON. In conclusion, industrial hemp improved plasma antioxidant status, reduced lipid peroxidation and decreased stress level thereby improving the performance and welfare of beef cattle

Effects of monensin and a blend of magnesium oxide on performance, feeding behavior, and rumen morphometrics of Zebu beef cattle fed high-starch diets

Abstract This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ± 37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit, and using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: (1) Control (CON) – a basal diet without additive inclusion; (2) Magnesium oxide blend (MG) – basal diet plus a magnesium-based product (pHix-up®, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); (3) Monensin (MON) – basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and (4) MG association with MON – basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 days. Blood samples were collected on days 0, 13, and 70 to determine D-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P < 0.05. Steers fed MG-containing diets consumed approximately 0.6 kg more dry matter per day than those fed diets without this additive (P = 0.01; 11.3 vs. 11.9 kg/day). The inclusion of MG in the diet increased (P = 0.02) the average daily gain (ADG). There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of body weight (BW) (P ≤ 0.03) for steers-fed diets with MG. Steers fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers fed MG + MON diets (MON × MG: P ≤ 0.04). Steers fed MON had 6.9% greater feed efficiency (P = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition.

143 Short- and long-term effects of heat stress in cow-calf pairs adapted to tropical and subtropical regions

Abstract Chronic exposure to high temperatures and humidity can limit beef cattle performance in tropical/subtropical environments, regardless of breed. Despite better heat adaptability compared with Bos taurus cattle, heat-stressed Bos indicus cattle also experience an increase in body temperature above the physiological limit. As body temperature increases, cascades of behavioral and physiological events are triggered to lessen heat load but often at the expense of productive outcomes. Contrary to other species and feedlot beef cattle, the effects of heat stress on physiology and performance of grazing cow-calf pairs have not been evaluated in detail, particularly for Bos indicus cattle. Preliminary data showed opposite outcomes to heat stress in Bos indicus vs. Bos taurus cattle, limiting the implications of the existing data generated from studies using beef and dairy Bos taurus cattle. This presentation will share some nutritional and management practices to mitigate heat stress in grazing beef cattle. Practices mentioned herein include altering the timing of body weight (BW) growth pattern (stair-step, SST) and immunomodulatory feed ingredient (IFI) supplementation for replacement beef heifers, and maternal access to shade to reduce heat load. For 100 d before the breeding season, Bos indicus-influenced beef heifers grazing warm-season grasses received a constant supplementation amount or SST strategy (50 d of low then 50 d of high supplementation), with or without IFI. Under severe heat stress conditions, IFI supplementation reduced heifer vaginal temperature but did not increase their growth and reproduction, whereas the SST strategy lowered internal body temperature, enhanced growth performance and pregnancy success compared with a conventional constant supplementation practice. Our group is also focused on the critical need to determine the specific effects of heat stress mitigation during pre- and postnatal phases on physiology and performance of Bos indicus-influenced cow-calf pairs. Study 1 evaluated the impacts of maternal access to artificial shade from 83 d prepartum until 50 d postpartum on body thermoregulation, performance, and physiology of beef heifers and their first offspring. Removing maternal access to shade led to greater maternal respiration rate, vaginal and body surface temperatures and reduced maternal body condition score and calf BW at birth. Nonetheless, offspring born from cows with no access to shade were remarkably heavier during a 60-d post-weaning period and had decreased plasma indicators of inflammation and positive effects to humoral immune response. Study 2 is a multi-year, USDA/NIFA-funded study designed to capitalize on the ability of cattle to reprogram physiological/immunological systems following exposure to stress during gestation. Study 2 combined gestational and postnatal heat abatement to enhance the overall growth/immune/reproductive performance of grazing Bos indicus-influenced cow-calf pairs. Partial data on long-term growth and reproductive performance, physiology, metabolome, and microbiome of both cows and their female offspring will be shared in this presentation.

397 Effect of corn harvest with a chopping head on performance of cattle grazing corn residue

Abstract The addition of stalk chopping equipment on combine heads has become more common. An advantage of grazing residue compared with baling, is the ability of cattle to select the more digestible plant parts (husk and leaf). Chopping may impact this ability and decrease the feeding value. Thus, this study was designed to evaluate the effects of chopping residue at harvest on grazing cattle performance. A cornfield (16 Mg grain/ha) was divided into 12 paddocks blocked by location within field and assigned randomly to be harvested using a chopping or non-chopping combine head, with 4 paddocks assigned to be grazed (1.05 ha) from each harvest method (HM) and 4 ungrazed. Growing steers [n = 40; body weight (BW) = 230 ± 3.5 kg] were stratified by BW and assigned randomly to a grazed paddock, with 6 steers in the west block and 4 steers in the east block, with 1 rumen canulated steer (484 ± 33 kg BW) being assigned to each of the east paddocks and used as diet samplers. This resulted in the same grazing pressure (2.9 animal units/ha) in grazed paddocks. Cattle were supplemented at 0.6 % of initial BW with a distillers dried grains plus solubles and mineral mix daily. Cattle grazed for 56 d resulting in 5.4 Animal Units Months/ha. Residue mass of three 0.58 m2 frames was sampled in each paddock before (d -1), during (d 36) and after grazing. Husks were collected from three 5.81 m2 areas per paddock at each of the three timepoints. For residue mass, there was a significant (P < 0.01) HM by time interaction. There was no difference (P = 0.34) in residue mass between HM prior to grazing. However, at 36 d into grazing, residue mass of standard was greater (P = 0.03) than chopped, and post-grazing residue mass of chopped was greater (P = 0.01) than standard. When husk (kg/ha) was evaluated, there was a significant (P < 0.01) HM by time by grazing interaction. Prior to grazing, there was no difference (P ≥ 0.66) in husk between the grazed and ungrazed paddocks within HM. However, husk was less (P < 0.01) for chopped than standard. On d 36, within HM, grazed had less (P < 0.01) husk than the ungrazed. However, within grazing status on d 36 there was no effect (P ≥ 0.52) of HM. Post-grazing there were no differences (P ≥ 0.19) in husk among treatments. Within grazed treatments there was greater (P < 0.01) husk prior to grazing initiation compared with both D36 and post-grazing which did not differ (P ≤ 0.85). Within ungrazed treatments, pre-grazing and D36 did not differ (P ≥ 0.10) in husk, however, husk was lesser (P > 0.01) at the post-grazing sampling. For ADG there was no difference (P = 0.20) between HM, with 0.37 and 0.31kg/d for standard and chopped, respectively. Overall, HM had no effect on grazing cattle performance.

133 Effect of feeding two different feed additives (Prime Force and Optipartum C+) on finishing cattle performance and carcass characteristics

Abstract A feedlot study was conducted to evaluate the effect of two feed additives, Prime Force (Furst-McNess Company, Rockford, IL) and Optipartum C+ (AB Vista, Plantation, FL), on finishing cattle performance and carcass characteristics. In this experiment, steers [n = 320; 390 ± 9.5 kg of body weight (BW)] were used and four treatments were evaluated in a total of 32 pens, with 10 steers per pen and 80 steers per treatment. Treatments were arranged in a 2 × 2 factorial and included a control diet with no additives; a diet containing Prime Force targeted at 68 g/steer daily; a diet containing Optipartum C+, targeted at 20 g/steer daily; and a diet containing a combination of both products (68 g/steer Prime Force and 20 g/steer Optipartum C+). Cattle were fed for 151 d, but treatments were imposed the last 67 d before slaughter (i.e., fed control diet to all cattle until d 84). Performance is for the total 151-d feeding period. No interaction between feed additives was observed for performance or carcass traits (P ≥ 0.41), therefore main effects are presented. Feeding Prime Force increased final BW (P < 0.04) when compared with cattle not fed Prime Force. A tendency was observed for greater adjusted final BW (P = 0.06) and ADG (P = 0.08) for cattle fed Prime Force compared with cattle fed no Prime Force. Cattle fed Prime Force had numerically greater intake (P = 0.11) than cattle fed no Prime Force, therefore gain to feed (G:F) was not impacted (P = 0.54). Ribeye area and fat depth were not different (P ≥ 0.17) for cattle fed Prime Force versus cattle that had no Prime Force added to the diet, but marbling was numerically improved (P = 0.11) due to Prime Force. Carcass-adjusted final BW (P = 0.11) was numerically greater for cattle fed Optipartum C+ and ADG tended (P = 0.09) to be greater for cattle fed Optipartum C+ compared with cattle fed no Optipartum C+. Dry matter intake was not different (P = 0.54) for cattle fed Optipartum C+ versus cattle with no Optipartum C+ in the diet, therefore G:F was numerically improved (P = 0.13) by the increase in ADG for cattle fed Optipartum C+. Ribeye area, fat, and marbling were not different (P ≥ 0.30) between cattle fed Optipartum C+ and those that did not receive Optipartum C+ in the diet. Incidence of liver abscesses was not affected by feeding either additive (P = 0.40). Based on results from this study, adding Prime Force to a finishing diet tended to improve BW and ADG compared with cattle not fed Prime Force. Feeding Optipartum C+ tended to increase ADG and improve G:F due to equal DMI when compared with diets with no Optipartum C+ added.

184 Effects of cattle hide color and changing environmental conditions at northern latitudes on feeder cattle performance and behavior

Abstract While suitable research has been done on the influence of climatic conditions on feeder cattle welfare, we have seen limited work done that assesses the relationship of hide color and cattle thermoregulation in response to extreme environmental changes, particularly of those seen at northern latitudes. Specifically, there is limited research on the effects of environmental stressors and cattle hide color on performance and intake. Therefore, the objective of this study is to evaluate feeder cattle performance in response to environmental conditions and hide color. Angus-based yearling steers [n = 40; average body weight (BW) = 409.28 kg were stratified by BW and hide color (red, white, and black) and were randomized into 10 pens at the Northern Agricultural Research Center in Havre, MT. Steers were on trial from 20 February 2023 to 11 July 2023 (141 d) and fitted with an electronic ear tag and adapted to the Vytelle system (Vytelle, Lenexa, KS) for 14 d prior to the start of the study. All 10 pens consisted of two electronic feed bunks equipped with an antenna to detect animal presence, load cells to measure feed disappearance and wireless transfer to a data-acquisition computer. Finishing diet (8.6% CP, 75% TDN) consisted of 69% corn, 21% corn silage, 10% wheat straw, and 0.45 kgּ animal-1ּ d-1 of beef grower pellet with a fortified mineral and vitamin package. Initial and final unshrunk BW were obtained on two consecutive days and averaged. Every 28 d during the experiment, steers were weighed prior to feeding and a measurement of coat depth was taken. Animal surface temperature was recorded via a FLIR E5xt thermal imaging camera on the same day of every week at 0730 h (prior to feeding) and 1330 h (6 h post feeding), for 20 wk. There was no difference in hair depth between the white hided steers and other treatments (P ≥ 0.26). However, there was a treatment effect (P = 0.01) of hide color on cattle surface temperature, with black and red hided steers averaging 2.85°C greater than white hided steers. There was no effect of treatment on average daily gain (P = 0.55) averaging 1.34 kg/d. Additionally, there was no treatment effect on average daily intake (P = 0.36), averaging 10.76 kg per day. There was a treatment effect on gain to feed efficiency (P = 0.05); however, post hoc means separation analysis showed no difference between treatments. In summary, although there were treatment effects on animal surface temperature, they were not reflected in animal performance.

68 Wildfire smoke simulations and the effects of smoke exposure on cattle acute phase protein response

Abstract The incidence of and acreage burned by wildfires are globally increasing, with predictions of more devastating fires in the future. The impacts of wildfire smoke exposure on have been of research interest over the years, although the scope of the literature is limited. Evaluating the effects of wildfire smoke exposure is challenging because of the unpredictability of fires, limiting the ability of researchers to evaluate this phenomenon. For this study, a wildfire smoke simulation was created to evaluate the effects of smoke exposure on beef cattle health, performance, and behavior. Heifers [n = 8 Angus x Hereford; body weight (BW) = 532 kg; 8 mo of age) were acclimated to individual pens in a completely closed barn for 7 d (d -7 to -1). Heifers were maintained in the barn for 36 d and exposed to wildfire smoke simulation for 7 consecutive days (d 0 to 7) while inside the barn. Heifers were individually fed alfalfa hay ad libitum, and feed intake was recorded daily. Health scores were collected daily from each heifer by 4 trained technicians, and blood samples were collected weekly for evaluation of acute phase proteins, cytokines, hormones, and hematology. Heifer behavior was recorded continuously using 4 cameras for the length of the study. Air quality was monitored daily every 1 min, using 2 air quality monitors. Preliminary data were analyzed using MIXED procedure of SAS. Heifers were considered the experiment unit serving as its own control, where variables were analyzed over time. Significance was set at P ≤ 0.05. Air quality, assessed with PM2.5, changed over time (P < 0.0001), reaching a daily average of 159 µg/m3 during the smoke simulation period. Although the air quality daily average was above the EPA standard (35 µg/m3), the smoke dissipated during the day, leading to wide variation in the 24 h-cycle (7.60 to 433 µg/m3; P < 0.0001), which might not truly represent air quality conditions during wildfires. Regardless, heifer plasma ceruloplasmin concentration increased over time (P = 0.05), reaching a peak during smoke exposure (29 mg/mL), which was maintained (P = 0.39; 27 mg/mL) for 1 wk post-smoke exposure before returning to nadir (23 mg/mL). An increase in acute phase proteins stimulated by smoke exposure has been observed in cattle naturally exposed to wildfires. Therefore, exposure to wildlife smoke might elicit an inflammatory response, potentially leading to reduced cattle performance, which could be accompanied by changes in behavior. This research was supported by the intramural research program of the USDA-NIFA, Award #2023-68008-39173.

PSXII-7 Forage quality and grazing dairy cattle performance as affected by the circadian rhythm: A meta-analytic investigation

PSXII-7 Forage quality and grazing dairy cattle performance as affected by the circadian rhythm: A meta-analytic investigation

PSXI-8 Effects of selected feed additives on feedlot cattle performance when fed diets containing rehydrated corn grain silage during adaptation period

PSXI-8 Effects of selected feed additives on feedlot cattle performance when fed diets containing rehydrated corn grain silage during adaptation period

Effect of exogenous cellulase pretreatment of straw-type fermented total mixed ration on digestibility and ruminal fermentation in growing beef cattle.

This study aimed to assess the impact of corn straw-based unfermented and fermented total mixed rations (TMR) supplemented with exogenous cellulase on the in vitro fermentation characteristics, growth performance, feeding behavior, apparent digestibility, rumen fermentation and digestive enzyme activities of Chinese Simmental bulls. Unfermented (direct spraying of exogenous cellulase onto TMR, TMR) and fermented (exogenous cellulase fermentation for more than 7 d, fermented total mixed rations [FTMR]) TMR were collected, dried, powdered and used as fermentation substrates. The fermentation liquid was ruminal fluid collected from Chinese Simmental bulls. The artificial rumen culture fluid were continuously cultured in vitro for 48 h. Based on the diets they were fed, 24 healthy Chinese Simmental bulls (average weight of 495.93 ±10.89 kg) were randomly divided into two groups, with 12 bulls in each group, which were fed TMR or FTMR. The study lasted 56 d. In in vitro experiments, the neutral detergent fiber degradability and total volatile fatty acid, propionate, iso-butyrate, iso-valerate and valerate concentrations were greater in the FTMR group (p<0.05) than in the TMR group. However, the methane production, pH and A/P of the FTMR group tended to be lower (p<0.05) than those of the TMR group. In the in vivo experiments, the average daily gain, eating rate, and feed efficiency of the FTMR groups were greater (p<0.05) than those of the TMR group. Similarly, the NDF degradability of the FTMR group was greater (p<0.05) than that of the TMR group. Compared to those in the TMR group, the concentrations of total volatile fatty acids, iso-butyrate, propionate and butyrate were greater in the FTMR group (p<0.05), and the A/P ratio was lower (p<0.05). Similarly, cellulase, xylanase, and β-glucosidase activities were greater (p<0.05) in the FTMR group than in the TMR group. Corn straw-based fermented total mixed rations supplemented with exogenous cellulase play a vital role in decreasing the structural carbohydrate content of TMR and ruminal methane production in vitro, improving nutrient digestion and absorption, optimizing rumen fermentation, and improving the growth performance of beef cattle.

Impact of Partial Oil Removal on Energy Content of Distillers Grains Plus Solubles for Finishing Cattle.

Two experiments evaluated the impact of the reduction in the percentage of corn oil remaining in distillers grains plus solubles (DGS) after the ethanol plant de-oiling process or by adding corn oil back to DGS following de-oiling on finishing cattle performance and nutrient digestion. Experiment 1 utilized 320 yearling steers (initial BW = 413 kg; SD = 25 kg) fed in 32 pens (10 steers/pen) and assigned to one of four treatments (n = 8 pens/treatment). The four treatments consisted of a blended DRC:HMC corn control diet (CON), de-oiled modified distillers grains plus solubles included at 40% of diet DM (DODGS), de-oiled modified distillers grains plus solubles included at 38% of diet DM plus 2% added corn oil (DODGS + Oil), and full-fat modified distillers grains plus solubles included at 40% of diet DM (FFDGS). The DODGS product contained 8.9% fat while the FFDGS product contained 11.6% fat. Dry matter intake (DMI) was impacted by treatment (p = 0.01) with steers fed DODGS having the greatest DMI and steers fed CON, DODGS + Oil, and FFDGS having lower DMI. Dietary treatment tended to impact ADG (p = 0.06) with steers fed DODGS and DODGS + Oil having greater gains than CON, with FFDGS being an intermediate. As a result of increased ADG, G:F differed between treatments (p < 0.01) with the greatest feed efficiency observed for steers fed DODGS + Oil and FFDGS. Including MDGS in the diet improved G:F by 6 to 11% compared to feeding DRC:HMC corn blend, with an improvement in G:F of 4.9 and 1.2% for DODGS + Oil and FFDGS, respectively, compared to DODGS. Hot carcass weight was impacted by dietary treatment (HCW; p = 0.05), with DODGS- and DODGS + Oil-fed steers having the heaviest HCW, CON steers having the lightest HCW, and FFDGS being an intermediate. Experiment 2 was a 5 × 4 unbalanced Latin rectangle digestion experiment with four diets, five ruminally cannulated steers, and five periods that utilized the same treatments as Exp. 1. Dietary fat measured 4.2, 6.0, 7.9, and 7.1% for CON, DODGS, DODGS + Oil, and FFDGS, respectively. Intakes of DM, OM, and energy as well as total tract fat digestibility and DE (Mcal/d) were not impacted by dietary treatment (p ≥ 0.46). When corn oil was added back to de-oiled MDGS, there was a negative impact on digestibility of OM (p < 0.01) and NDF (p = 0.07) compared with DODGS, FFDGS, and CON. Partially removing oil from modified distillers grains plus solubles did not significantly impact cattle performance, carcass traits, energy content, or digestibility when MDGS was included at approximately 40% of diet DM.

Characterization of smallholder irob cattle production system: contributions to develop a breeding program.

An exploratory survey (i) to investigate livestock production system, reproductive and production performance of Irob cattle and (ii) to recognize constraints to cattle production was conducted in eastern Tigray zone, northern Ethiopia. Six tabias (the smallest administrative unit consisting of several villages) were chosen using purposive sampling method and households from each tabia were randomly selected. Mixed crop-livestock farming system dominates the study area. Overall herd size was 5.3 ± 2.7, with each herd comprising of 1.7 ± 1.2 cows, 1.4 ± 0.9 oxen, 0.5 ± 0.7 heifers, 0.5 ± 0.7 bulls and 1.2 ± 0.9 calves. Cattle are kept for draught power (index = 0.43), milk (index = 0.32), income (index = 0.15), manure (index = 0.06) and crop threshing (index = 0.04). Major feed resources in the study area were natural pasture, crop residue and cactus pear (Opuntia ficus-indica). Overall mean (± SD) for age at first services (AFS), age at first calving (AFC), calving interval (CI), days open (DO), daily milk yield (DMY) and lactation length (LL) was 28.3 ± 3.9 months, 37.4 ± 5.5 months, 15.5 ± 4.1 months, 6.5 ± 1.8 months, 1.7 ± 0.4L and 7.4 ± 2.0 months, respectively. There was no significant (p > 0.05) difference in performance traits between districts. Well-known cattle production constraints in order of significance were feed, disease and parasites, AI, water and veterinary service. In conclusion, the study shown importance of taking into account the production environment in developing breed improvement program and recommends fit management system.

Economic impact of the use of anthelmintics in beef cattle in the rearing phase

The objective of the present study was to evaluate the effectiveness of anthelmintics and their influence on the performance of beef cattle supplemented during the rearing period, carrying out a cost analysis of the different treatments. 120 Nelore animals were used, with an average of 9 months of age, 60 males and 60 females. The animals were distributed into 6 groups of males and 6 of females, five treated with anthelmintics and a control group, G1: Moxidectin 1%, G2: Levamisole Phosphate 18.8%, G3: Ivermectin 0.8% + Albendazole Sulfoxide 10%, G4: Albendazole 10%, G5: Fenbendazole 10%, G6: Control (saline solution). Individual weighing was carried out using an electronic scale, at the beginning of the experiment (D0), fourteen days later (D14) and at the end of the experiment (D90), with performance assessed through weight gain (GP). Fecal collections were carried out on the same days as weighing, with individual egg counts per grams of feces (OPG) and stool culture to identify helminth genders. Economic viability was calculated based on the price of the calf and total production cost. The data obtained was subjected to the 5% Tukey test and the effectiveness of the anthelmintics was evaluated using the RESO program. It is concluded that the anthelmintics evaluated were effective, with the exception of Ivermectin 0.8% + Albendazole Sulfoxide 10%, which showed anthelmintic resistance. The anthelmintic treatment provided the animals with better performance, with the greatest weight gain observed in animals treated with Moxidectin 1%, demonstrating better economic indices.

Licorice Extract Supplementation Benefits Growth Performance, Blood Biochemistry and Hormones, Immune Antioxidant Status, Hindgut Fecal Microbial Community, and Metabolism in Beef Cattle.

This study aimed to evaluate the effects of licorice extract (LE) on growth performance, nutrient apparent digestibility, serum index (biochemistry, hormones, humoral immunity, and antioxidant function), hindgut fecal microbiota, and metabolism in beef cattle. In total, 12 male yellow cattle aged 12 months were divided into two groups (6 cattle per group): the basal diet (CK group) and the basal diet supplemented with 2 g/kg LE (CHM group). The entire experimental phase lasted for 120 days, including a 30-day pre-feeding period. Compared to the CK group, the average daily gain, crude fiber, calcium, and crude protein nutrient digestibility were greater on d 30 than d 60 (p < 0.05) and the feed meat ratio was lower for LE addition (p < 0.01). In terms of serum indexes, the insulin and nitric oxide contents were enhanced on d 30, the alkaline phosphatase level was improved on d 60, and the levels of albumin, immunoglobulin A, and catalase were increased on d 90 (p < 0.05). In contrast, the cholesterol content was lower on d 60 for LE addition compared with the CK group (p < 0.05). The higher enrichment of [Eubacterium]-oxidoreducens-group, p-2534-18b5-gut-group, and Ileibacterium were observed in the CHM group (p < 0.05), while the relative abundances of Gallibacterium and Breznakia in the CHM group were lower compared with the CK group (p < 0.05). In addition, the differential metabolites related to healthy growth in the CHM group were increased compared with the CK group. And there was a close correlation between hindgut microbiota and metabolic differentials. In general, LE has a promoting effect on the growth performance and health status of beef cattle over a period (30 to 60 days).

Study of Plasma Biochemistry and Plasma Metabolomics Differences in Montbéliard and Holstein Backcross and Holstein Heifers.

Holstein cattle are the main breed of dairy cattle in China. However, given the high degree of purebred selection of Holstein cattle, Chinese dairy cattle are increasingly being characterized by poor disease resistance, poor quality, and declining fertility. In this study, using Montbéliard × Holstein cattle as females and Montbéliard bulls as males for backcross breeding, we sought to provide a reference for improving the quality and performance of Holstein cattle and enhancing the efficiency of dairy farming. On the basis of similar physiological status and age, we selected 24 Montbéliard and Holstein backcross heifers and 11 Holstein heifers fed the same formula for comparative analyses. Plasma samples collected for plasma biochemical index analyses revealed that the content of ALB and BUN in the Montbéliard and Holstein backcross heifers was 20.83% (31.62 g/L to 26.17 g/L) and 42.36% (6.89 mmol/L to 4.84 mmol/L) higher than in the Holsteins (p < 0.01). The ALB/GLB (0.90 to 0.60, p < 0.05) was significantly higher in Montbéliard and Holstein backcross heifers than in Holstein heifers. Similarly, the activity of CAT in the backcross heifers was 61.28% (4.29 U/mL to 2.66 U/mL) higher than that in the Holstein heifers (p < 0.05). Although the activity of GSH-Px in the backcross heifers also showed an increasing trend, the difference did not reach the level of statistical significance (p = 0.052). Compared with Holstein heifers, the concentrations of IgA, IgG, and IL-4 were elevated by 32.52% (24.90 μg/mL to 18.79 μg/mL, p < 0.01), 13.46% (234.32 μg/mL to 206.53 μg/mL, p < 0.01), and 14.59% (306.27 pg/mL to 267.28 pg/mL, p < 0.05), and the contents of IL-6 and TNF-α were decreased by 15.92% (215.71 pg/mL to 256.55 pg/mL, p < 0.01) and 32.17% (7.17 ng/mL to 10.57 ng/mL, p < 0.01) in the plasma of Montbéliard and Holstein backcross heifers. Among the experimental heifers, five animals from each of the two groups were selected for plasma metabolomic analysis based on untargeted liquid chromatography-mass spectrometry. A comparison of the differential metabolites between the two heifer breeds revealed an up-regulation of d-glucuronic acid, s-glutathionyl-l-cysteine, and oleic acid levels in the backcross cattle compared with those in the Holstein heifers. We speculate that changes in the levels of these metabolites may be associated with an enhancement of the anti-inflammatory, antioxidant, and immune systems in these backcross heifers. Collectively, our findings in this study indicate that compared with 12-month-old purebred Holstein heifers, Montbéliard and Holstein backcross heifers of the same age are characterized by higher antioxidant capacity and immunity.

Productive and reproductive performance of cattle in the tropical part of India

The assessment of productive and reproductive traits helps in identifying animals with superior germplasm in comparison to their population mean which helps in selecting animals for breeding purposes. The early detection of low- performing animals based on the parameters considered for the evaluation of productive and reproductive traits in the study can help in culling animals at an early age, thus saving the cost of maintenance or losses for dairy farmers. Overall, it was observed that the productive and reproductive performance of cross-bred cows was better as compared to the buffaloes and non-descript cows. Therefore, the study advises taking the following steps; record keeping, regular testing for various diseases, balanced ration, maintenance of proper hygiene, availability of nearby veterinary services, and upgradation of non- descript animals to exploit maximum production potential at farmers’ level.