The effects of shade on performance,carcass classes and behaviour of heat-stressed feedlot cattle at the finisher phase

The study aimed to determine the impact of shade on the performance, carcass class and behaviour using 146 crossbred steers and bulls during the finishing phase on a commercial feedlot in February. Treatments were (1) shade and (2) no shade. Average daily gain (ADG), DMI, and feed efficiency were measured, and hot carcass weight (HCW) and grades were collected at slaughter. The proportion of animals within a pen engaged in various behavioural activities (standing, lying, feeding and panting) was recorded. Five randomly selected individual animals per treatment were monitored every 2 min between 0700 and 1600 hours to determine the time spent on each of the above activities. Shade improved the final body weight (P  <  0.0001), ADG (P  =  0.079), and HCW by 8.33 kg (P  <  0.05). Shade increased (P  <  0.05) the feeding activity but decreased (P  <  0.05) panting behaviour. Shade conferred an economic benefit of R2.03 head⁻¹ week⁻¹, and thus would reduce heat stress and increase the feedlot profitability.     

Effect of salinomycin supplementation on characteristics of digestion and feedlot performance of cattle

One hundred fifty large-frame British-cross calves, 75 heifers and 75 steers averaging 220 kg, were used in a 187-d growing-finishing trial to study the influence of dietary salinomycin levels of 0, 5.5, 11, 16.5 and 22 mg/kg on rate and efficiency of gain. The basal diet to which the ionophore was added was composed largely to steam processed grains, and contained 3% supplemental fat. Performance responses to salinomycin supplementation were similar for steers and heifers. Rate of gain was not influenced (P greater than .20); however, feed conversion was improved by an average of 5% at the 11- to 22-mg/kg levels of salinomycin supplementation (P less than .05). Although not necessarily mutually exclusive, this improvement in feed conversion could be accounted for as either a 5% increase in the net energy value of the diet (P less than .05) or a 10% reduction in maintenance requirement (P less than .10). Four steer calves (234 kg) with cannulae in the rumen and proximal duodenum were used in a 4 X 4 Latin-square design trial to determine the influence of salinomycin supplementation on characteristics of digestion. Four levels of supplementation (0, 55, 11 and 16.5 mg/kg) were evaluated using the same basal diet as in the performance trial. Total tract digestion of organic matter, acid detergent fiber, starch and protein was not significantly altered by salinomycin supplementation. However, ruminal digestion of organic matter was reduced 6.2% (P less than .05). Neither ruminal degradation of feed protein nor net microbial synthesis was significantly altered.(ABSTRACT TRUNCATED AT 250 WORDS)     

Shade and wind barrier effects on summertime feedlot cattle performance.

In each of three summertime trials conducted over consecutive years, approximately 110 predominantly black and black-white-face steers were blocked by weight and randomly allotted to one of 16 pens in a 2x2 factorial arrangement of treatments. Factors consisted of cattle being fed in facilities with or without wind barriers and with or without shade. Steers were fed dry-rolled corn-based diets (1.43 Mcal/ kg, NEg). Mean starting date and days on feed were June 26 and 79, respectively. In unshaded areas, temperature and humidity averaged 21.6 degrees C and 77.9%, and the blackglobe-humidity index (BGHI) at 1500 averaged between 84.0 and 89.1. Each of four 6.1-x6.1-m structures (mean height = 3.4 m) with white steel roofs provided shade (2.65 m2/steer) for two pens. In facilities with wind barriers provided, airflow was reduced from the north and northwest by a 25-m-wide shelterbelt containing six rows of trees. For cattle fed in pens with wind barriers, shade increased (P<.05) gain from 0 to 56 d and decreased (P<.05) DMI/ADG from 0 to 28 d. Differences (P<.05) in performance were not found between shaded and unshaded cattle in any portion of the feeding period for cattle fed in the pens without wind barriers and over the entire feeding period in either type of facility. The shade response in pens with wind barriers seemed to be greater the 1st yr than in subsequent years. Differences in weather patterns among years, especially air temperature, humidity, and solar radiation, may partially explain this interaction. Also, in yr 1, cattle tended to have greater fat thickness at finish than in yr 2 and 3. Correlations between BGHI and DMI tended to be greater during the early portion of the trial (0 to 28 d) than over the entire trial. Correlations between the difference in BGHI under shade vs no shade and percentage of shade use had the greatest magnitude and were significant only in the first 28 d vs over the entire feeding period. Although no heat-related cattle deaths occurred in this study, results suggest that shade improves cattle performance in the summer when they are fed in facilities with winter wind protection available and have not become acclimated to hot conditions. Once cattle are acclimated or hot conditions subside, compensation by unshaded cattle offsets much of the initial benefits of providing shade.     

Effects of previous grazing nutrition and management on feedlot performance of cattle

Management strategies designed to improve grazing animal performance can influence feedlot performance and carcass traits both positively and negatively. In spite of the economic relevance of potential interactions between grazing and finishing performance, controlled experiments evaluating integrated production systems are limited in number. Effects of grazing treatments can result from, or be overshadowed by, changes in gut fill, thus making it difficult to assign precise costs to different phases of production. Published reports have considered the effects of stocking rate, duration of grazing, forage characteristics, supplementation, and growth-promoting implants on subsequent finishing performance. Improvements in cattle performance attributed to changes in stocking rate generally have been neutral to positive with respect to effects on finishing performance. Comparisons among forages have led to the suggestion that forage species may contribute to differences in gastrointestinal fill of grazing cattle, thereby influencing gain and efficiency during the subsequent finishing phase. Creep-feeding suckling calves generally has increased preweaning performance but has had relatively little influence on performance during the subsequent finishing phase. Grain supplementation of stocker cattle during the grazing period has improved grazing performance, but effects on subsequent feedlot performance have been inconsistent. Potential carryover effects from protein and mineral supplementation also have been inconclusive. Lack of congruence among studies is puzzling but may be the consequence of highly varied production systems, differences in experimental procedures, and changes in gut fill or mass of internal organs. Based on the studies reviewed, the expression or absence of compensatory growth during the finishing phase appears to be related to the nutritional quality of forages utilized in the grazing period, with higher quality forages tending to yield greater compensatory effects. The bulk of evidence with suckling cattle and stocker implants suggests that effects on subsequent finishing performance are minimal. Attention is drawn to the noticeable lack of research pertaining to integrated production systems. A more thorough understanding of the interactions among grazing nutrition and management, finishing performance, and carcass traits is needed to facilitate greater economic exploitation of these relationships.     

Effect of salinomycin level on nutrient digestibility and ruminal characteristics of sheep and feedlot performance of cattle

A sheep digestion trial and two feedlot trials with cattle were conducted to study effects of an ionophore, salinomycin, on nutrient digestibility, ruminal metabolism and cattle performance. In trial 1, addition of salinomycin at 5.5, 11 or 22 ppm to 60% concentrate diets fed to ruminal-cannulated rams had no effect (P greater than .05) on apparent digestibility of dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) or starch in comparison with control diets. Apparent nitrogen (N) digestibility was increased (P less than .05) in animals fed salinomycin. Salinomycin did not affect total volatile fatty acid (VFA) concentrations in the rumen, but resulted in a linear (P less than .05) increase in molar proportion of propionate and a linear (P less than .05) decrease in molar proportions of acetate and butyrate and in acetate:propionate ratios. Shifts in VFA proportions were fully expressed within 4 d after salinomycin was added to the diet. In trial 2, salinomycin was added at 5.5, 11, 22 or 33 ppm to 85% concentrate diets fed to finishing steers. Salinomycin level had a quadratic effect (P less than .05) on daily weight gain and resulted in a quadratic (P less than .05) decrease in feed intake with a resultant average improvement of 10.3% in feed efficiency. Salinomycin (5.5, 11, 16.5 or 22 ppm) and monensin (22 ppm) were added to 90% concentrate diets in trial 3 and produced increased rates of gain without affecting feed intake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of cattle age, forage level, and corn processing on diet digestibility and feedlot performance

Three experiments were conducted to determine the effects of cattle age and dietary forage level on the utilization of corn fed whole or ground to feedlot cattle. In Exp. 1, 16 steers were used to investigate the effects of cattle age and corn processing on diet digestibility. Two cattle age categories were evaluated (weanling [254 +/- 20 kg BW] and yearling [477 +/- 29 kg BW]; eight steers per group), and corn was fed either ground or whole to each cattle age category. Cattle age and corn processing did not affect (P > 0.10) diet digestibility of DM, OM, starch, CP, NDF or ADF, and no interactions (P > 0.10) between these two factors were detected. In Exp. 2, the effects of forage level and corn processing on feedlot performance and carcass characteristics were evaluated. One hundred eighty steers (310 +/- 40 kg BW) were allotted to 24 pens, and were fed one of the following diets: high-forage (18.2% corn silage) cracked corn (HFCC); high-forage shifting corn (whole corn for the first half of the trial, then cracked corn until harvest; HFSC); high-forage whole corn (HFWC); low-forage (5.2% corn silage) cracked corn (LFCC); low-forage shifting corn (LFSC); and low-forage whole corn (LFWC). For the high-forage diets, steers fed cracked corn had 7% greater DMI than those fed whole corn, whereas for the low-forage diets, grain processing did not affect DMI (interaction; P = 0.02). No interactions (P > 0.10) between forage level and corn processing were found for ADG and G:F. Total trial ADG and G:F, and percentage of carcasses grading USDA Choice, and carcass yield grade were not affected (P > 0.10) by corn processing. Cattle with fewer days on feed grew faster and more efficiently when cracked corn was fed, whereas cattle with longer days on feed had greater ADG and G:F when corn was fed whole (interaction; P < 0.10). In Exp. 3, the effects of forage level and corn processing on diet digestibility were evaluated. The high-forage cracked corn, high-forage whole corn, low-forage cracked corn, and low-forage whole corn diets used in Exp. 2 were fed to 16 steers (350 +/- 27 kg BW) in a digestion trial. No interactions (P > 0.10) between forage level and corn processing were detected for starch digestibility. Forage level and corn processing (grinding) did not affect (P > 0.10) diet DM, OM, starch, CP, and NDF digestibility. Processing corn did not provide additional benefits to feedlot cattle performance under these experimental conditions.     

Effects of dry corn gluten feed on feedlot cattle performance and fiber digestibility

Effects of dry corn gluten feed (DCGF) on feedlot cattle performance and fiber digestibility were investigated. In Trial 1, 120 growing steers were fed corn silage-based diets containing 0, 40, 60 or 80% DCGF. Increasing levels of DCGF resulted in a curvilinear response in gain (P less than .05) and a linear increase in feed/gain (P less than .01). When the same steers subsequently were fed the same levels of DCGF in corn-based diets (Trial 2), increasing the percentage of dietary DCGF resulted in a linear decrease in gain (P less than .01) and a linear increase in feed/gain (P less than .01). In Trial 3, 46 crossbred steers were fed individually in a 2 x 2 factorial design to determine effects of 60 or 80% dietary high-moisture corn (HMC) or DCGF on feedlot cattle performance. Steers fed HMC had faster (P less than .08) and more efficient (P less than .05) gains than those fed DCGF, which had greater feed intakes (P less than .05). In Trial 4, 120 Angus crossbred steers were used to compare effects of 20 or 40% dietary HMC or DCGF on feedlot performance. Steers fed diets containing 40% HMC or DCGF had greater gains (P less than .01) and feed intakes (P less than .01) than those fed 20% diets. Steers fed HMC gained more efficiently than those fed DCGF (P less than .01). In an in situ trial, 0, 40, 60 or 80% dietary DCGF did not affect in situ DCGF DM or NDF disappearance. When DCGF was fermented in vitro in combination with corn silage, increasing the level of DCGF from 0 to 100% resulted in a linear increase (P less than .01) in 24 and 48 h NDF disappearance. These results suggest that at high dietary levels DCGF will support feedlot cattle gains that are nearly equal to those of cattle fed corn silage but somewhat less than those fed corn.     

Effect of enrofloxacin therapy on shipping fever pneumonia in feedlot cattle

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in the feedlot. Forty-six diseased animals were divided randomly into three groups A, B and C, containing 17, 19 and 10 animals, respectively; the animals in group A were injected intramuscularly once daily for three consecutive days with 2.5 mg/kg of enrofloxacin, those in group B with 5 mg/kg of enrofloxacin and those in group C with 10 mg/kg of oxytetracycline. Clinical, serological, production and respiratory functional observations were recorded. The animals were clinically cured after the three day treatment except for three in group A and two in group C. These five animals made a clinical recovery after a three day booster treatment with a dose of 5 mg/kg enrofloxacin. The changes in respiratory gas exchange values induced by shipping fever were completely reversed 15 days later, suggesting that there had been no irreversible lung damage. The daily weight gains and the arterial blood gas values of the three groups of treated cattle were not significantly different. The high efficacy of the low dosage of enrofloxacin in this clinical syndrome may be explained by its antibacterial activity against Pasteurella species and Mycoplasma species. This field trial supports the in vitro studies which suggested than enrofloxacin is an appropriate therapy in cases of shipping fever.     

Impacts of shade on cattle well-being

Open in a separate window

Environmental temperatures represent one of the most detrimental stressors to livestock production systems. Dairy cattle are especially susceptible and common means for reducing thermal load include sprinkler systems (Tresoldi et al., 2018) and shade structures (Beggs et al., 2019). Less is known regarding implementation of shade structures in the beef cattle industry. Edwards-Callaway et al. (2021) present a comprehensive review on the benefits of shade provision to beef cattle at multiple stages of the life cycle.     

The effect of floor space allowance on feedlot performance and on behaviour of Israeli-Friesian male cattle

Four groups of Israeli-Friesian male cattle were fattened in pens with concrete slatted floors from an initial live weight of 138 kg up to 450 kg at slaughter. Floor space per animal differed between groups, of which two were fed ad lib. and two restricted. One group had an adjoining uncovered yard. Both DM intake and daily gain different significantly from the 150th day to slaughter. The differences were directly related to floor space allowance per animal. Animals of the smaller space allowance had a significantly higher dressing percentage, but they were not significantly fatter.     

The effect of bovine viral diarrhea virus infections on health and performance of feedlot cattle

The aim of this study was to investigate the effect of bovine viral diarrhea virus (BVDV) infections (unapparent acute infections and persistent infections) on the overall health and performance of feedlot cattle. Calves from 25 pens (7132 calves) were enrolled in the study. Overall and infectious disease mortality rates were significantly higher (P < 0.05) in pens categorized at arrival as positive for type I BVDV and lower in pens that were positive for type II BVDV than in negative pens. Mortality attributed to BVDV infection or enteritis was significantly more common (P < 0.05) in the pens containing persistently infected (PI) calves than in pens not containing PI calves (non-PI pens). There were no statistically detectable (P > or = 0.05) differences in morbidity, overall mortality, average daily gain, or the dry matter intake to gain ratio between PI and non-PI pens. Although type-I BVDV infections in feedlots appear to contribute to higher mortality rates, the presence of PI calves alone does not appear to have a strong impact on pen-level animal health and feedlot performance.     

Effect of water sprinkling on incidence of zoonotic pathogens in feedlot cattle

Heat stress and dusty conditions are common challenges for cattle during the summer, and a typical method of alleviating these problems involves sprinkling cattle and pens with water. The effect of sprinkling water on the incidence of zoonotic pathogens has not been previously studied. Four pens of heifers (n = 41) were cooled using sprinklers, and four pens (n = 43) served as controls. Heifers were crossbred Charolais, with white and red hair coats. Sprinkling was initiated when cattle were on full concentrate feed (July). Fecal samples, hide swipes, and BW were collected on d 0, 28, 63, 95, and 98. Average daily gain, DMI, and G:F were calculated, and carcass traits were collected 36 h after processing. Performance data were analyzed as a randomized complete block design, and zoonotic pathogen data were analyzed using chi2 analysis. Sprinkling tended (P = 0.054) to increase the incidence of fecal Salmonella spp. populations on d 98, but simultaneously tended to decrease (P = 0.058) the Escherichia coli O157:H7 incidence on hides on d 98. The most prevalent Salmonella serovars in this study were Kentucky, Muenster, Meleagridis, and Cerro. Performance measures and carcass traits did not differ between treatments (P > 0.10). Under our conditions, sprinkling cattle with water did not affect the incidence of zoonotic pathogens in feces or on hides.     

Poor growth performance associated with hypocupremia in Hawaiian feedlot cattle.

Poor feedlot performance in native Hawaiian feedlot cattle was investigated. Cattle were first noticed to be affected 40 to 60 days after arrival at the feedlot, as judged by their retarded growth, when compared with penmates. Marked hypocupremia was detected in all 10 cattle examined, irrespective of time in the feedlot. Clinical signs and upper digestive tract lesions in 8 of the 10 cattle suggested secondary involvement of bovine papular stomatitis. The poor performance was attributed primarily to the hypocupremia, as a result of molybdenum-accentuated copper deficiency in forage on the ranch of origin.     

Effects of feeding growing cattle high-concentrate diets at a restricted intake on feedlot performance

Three trials were conducted to compare effects of restricted intake of high-concentrate diets vs ad libitum intake of corn silage diets during the growing phase on feedlot cattle performance. In Trial 1, 120 steers (initial BW, 246 kg) were fed 1) a corn silage-based diet ad libitum, 2) a high-moisture corn-corn silage-based diet with intake restricted to a level 20% less than that of the corn silage diet or 3) a high-moisture corn-based diet with intake restricted to a level 30% less than that of the corn silage diet. Steers fed the 20% restricted corn-corn silage-based diet tended (P = .07) to gain slower than those fed the corn silage or 30% restricted high-concentrate diet. Feed efficiency and diet digestibility were greatest for steers fed the 30% restricted-intake, high-concentrate diet (P less than .01). Performance of steers during the subsequent 118-d finishing period was not affected (P greater than .65) by source of energy during the growing period. In Trial 2, ADG of steers fed the 30% intake-restricted, high-concentrate diet was lower (P less than .01) than that of steers with ad libitum access to corn silage. During the 84-d growing period, steers fed supplemental blood meal had 8.3% greater gains and a 6% greater efficiency of feed use than those fed supplemental soybean meal (P less than .01). Monensin did not affect (P = .82) performance of steers fed 30% restricted-intake diets. During the 76-d finishing period, gains and feed conversion were improved (P less than .01) for steers fed the restricted-intake diet in the growing period compared with those given ad libitum access to corn silage. During the growing period in Trial 3, ADG of steers restricted-fed an all-concentrate diet were slightly greater (P less than .10) than ADG of those given ad libitum access to corn silage. Gains did not differ (P = .37) during the subsequent finishing period when steers were switched to 85 or 100% concentrate diets. We concluded that intake of all concentrate diets can be restricted to achieve gains equal to those of steers given ad libitum access to corn silage-based diets without detrimental effects on finishing performance.     

Effect of feed delivery fluctuations and feeding time on ruminal acidosis, growth performance, and feeding behavior of feedlot cattle

Research was conducted to determine whether fluctuations in the amount of feed delivered and timing of feeding affect ruminal pH and growth of feedlot cattle. In Exp. 1, the effects of constant (C) vs. fluctuating (F) daily feed delivery on ruminal pH were assessed in a crossover experiment (two 28-d periods) involving six mature, ruminally cannulated steers. The diet consisted of 86.8% barley grain, 4.9% supplement, and 8.3% barley silage (DM basis) and was offered ad libitum for 2 wk to estimate DMI by individual steers. Steers in group C were offered a constant amount of feed daily equal to their predetermined DMI, whereas steers in group F were offered 10% more or less than their predetermined DMI on a rotating 3-d schedule. Ruminal pH of each steer was measured continuously via an indwelling electrode placed in the rumen during the last 6 d of each period. Mean pH tended to be lower (0.10 units) for F than C (5.63 vs. 5.73; P = 0.15), and ruminal pH of steers in group F tended to remain below 5.8 (P = 0.03) or 5.5 (P = 0.14) for greater proportions of the day than steers in group C. Inconsistent delivery of feed lowered ruminal pH, suggesting increased risk of subclinical acidosis. In Exp. 2, a 2 x 2 factorial was used to study the effects of pattern (C vs. F) and feeding time (morning [0900] vs. evening [2100]) on the feeding behavior and performance of 234 (310 +/- 23 kg) Charolais x Hereford beef steers during backgrounding and finishing phases over 209 d. One pen per treatment was equipped with a radio frequency identification (GrowSafe Systems Ltd., Airdrie, Canada) system that monitored bunk attendance by each steer throughout the trial. Pattern of feed delivery did not affect (P = 0.16) DMI (7.36 kg/d), ADG (1.23 kg/d), G:F (0.17), or time spent at the bunk (141 min/d), nor were pattern of feed delivery x time of feeding interactions observed (P = 0.18). Late feeding increased (P < 0.05) daily DMI (7.48 vs. 7.26 kg), ADG (1.28 vs. 1.00 kg/d), and G:F (0.21 vs. 0.15). These studies indicate that the risk of subclinical acidosis was increased with fluctuating delivery of feed, but the greater risk of acidosis did not impair growth performance by feedlot cattle. Consequently, daily intake fluctuations of 10% DMI or less that do not alter overall intake by feedlot cattle are unlikely to have any negative consequences on growth performance.     

Effects of placing cattle on feed at two-month intervals and housing on feedlot performance and carcass grades

A 5-yr study was conducted involving the placement of yearling steers on feed at 2-mo intervals under three different housing systems. A total of 3,571 steers (180 pens) initially averaging 318 kg was used. Evaluations were made for DM intake, ADG, feed efficiency (FE), carcass quality (QG), and yield grades (YG). Cattle were assigned to either an open lot with overhead shelter (S), an open lot without overhead shelter (NS), or an open-front confinement building (C). Each treatment consisted of two lots of 20 steers each per interval per trial. Corn grain provided 85% of the energy; the remainder was supplied by corn silage and protein supplement. Cattle were fed 140 to 180 d to achieve an average slaughter weight of 500 kg. The main effects of year (Y), month (M), and housing (H) affected DM intake, ADG, FE, and final live weight (P less than .01). The interactions for Y x M, M x H and Y x M x H affected ADG (P less than .05). Month and H affected hot carcass weight (P less than .01). Year affected YG, and year and month affected QG (P less than .01). Month effects on DM intake and ADG indicated that cattle started in May had the highest intake and ADG (P less than .05) and that cattle started in November had the lowest (P less than .05) DMI and ADG. Month effects on FE indicated that cattle were most efficient when placed on feed during March, May, and July (5.82, 5.72, and 5.66 kg DM/kg gain; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Organic additives used in beef cattle feedlot: Effects on metabolic parameters and animal performance

Organic additives are recently being used in animal diets owing to their ability to control metabolic issues and result in better animal performance. Specifically, the organic additive Fator P^® presents an additional advantage that is to cause a lesser greenhouse gas emission. This study evaluated whether Fator P^® intake changes ruminal parameters or animal performance of beef cattle. Evaluations were carried out in a feedlot experiment divided into growing (46 days; two diets [control mix—CM and standard mix—SM] and finishing (lasted 83 days; four diets: CM, SM, Fator P^® + virginiamycin, and Fator P^® alone [FP]) trials. Animal performance study involved 48 animals allocated to 12 collective pens in completely randomized experimental design. Ruminal parameters were evaluated in separate metabolism study developed carried out using individual pen with four steers. During growing trial, FP diet resulted in higher (p < 0.05) dry matter intake (DMI) and ruminating time. In the finishing trial, diets containing Fator P^® resulted in higher DMI than obtained with CM. Most of the ruminal parameters did not differ (p > 0.05) among dietary treatments. Therefore, Fator P^® represents a viable and safe strategy for supplementation to beef cattle finished using high‐concentrate diet in feedlot systems.