Growth Of Beef Calves Research Articles

Total and pathogen-specific serum Immunoglobulin G concentrations in neonatal beef calves, Part 2: Associations with health and growth.

The association of poor transfer of passive immunity (TPI) with negative health outcomes is extensively researched in dairy calves. However, few field studies have examined the effect of total and particularly pathogen-specific Immunoglobulin G (IgG) concentrations on pre-weaning health and growth of beef calves. Hence, the objective of this study was to determine the association of total and pathogen-specific IgG concentrations against selected pathogens associated with neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) and the odds of pre-weaning treatments, mortality, and the growth of newborn beef calves. A total of 420 serum samples from 1- to 7-day old beef calves born on 6 farms in Alberta, Canada, were available for this observational study. Serum samples were analyzed by radial immunodiffusion for total IgG concentration and by enzyme-linked immunosorbent assays for pathogen-specific IgG concentrations against Escherichia coli (E. coli), bovine Rotavirus (BRoV), Cryptosporidium parvum (C. parvum), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza Virus Type 3 (PI-3), Bovine Respiratory Syncytial Virus (BRSV), and Bovine Herpesvirus Type 1 (BHV-1). Data about the individual dam- and calf-level risk factors, calf treatments, mortality, and birth and weaning weights were collected. Multivariable multilevel logistic and linear regression models were built to evaluate the association of total and pathogen-specific IgG concentrations with the odds of mortality and average daily gain (ADG), respectively, while their association with the odds of pre-weaning treatment was established by univariable logistic regression analysis. The odds of calves with IgG concentrations <10g/L of getting treated (OR 7.9, 95 % CI 2.7-23.7) and dying (OR: 18.5, 95 % CI: 3.7-93.4) were higher than for their counterparts (P<0.0001). Calves with IgG concentrations <24g/L also had higher odds of dying (OR: 10.1, 95 % CI: 2.6-40.2) and had lower ADG (-0.09kg, SE: 0.03, P<0.002) than calves with IgG concentrations ≥24g/L. Higher BVDV-specific IgG concentration was protective against mortality (OR: 0.97, 95 % CI: 0.96-0.99, P<0.001). This study highlights the negative association of inadequate TPI with health and growth of beef calves and thus, the need to refine protocols for dam vaccination and colostrum intervention in cow-calf operations to meet these higher IgG targets.

Effects of Dietary Enrichment with Olive Cake on the Thyroid and Adrenocortical Responses in Growing Beef Calves.

Agro-industrial by-products incorporated into livestock feed formulations can positively impact feed costs and promote a circular bio-economy. Italy produces significant amounts of olive cake (OC), a by-product of olive oil extraction, with the potential for incorporation into bovine diets. However, information on its effects on endocrine responses in growing beef calves is lacking. Forty-eight Limousines randomly allocated to dietary treatment (control or 10%-OC or 15%-OC inclusion) were segregated according to sex and body weight. Serum concentrations of TSH, thyroid hormones, and cortisol were measured on day 0, day 56, and at the end of the trial on day 147. Circulating TSH, total (T3, T4) and free (fT3, fT4) iodothyronines, and cortisol concentrations were all within the normal physiological ranges, with no significant effect imparted by diet. However, the diet × time interaction was significant for T3. The cortisol, T3, T4, and fT4 registered on day 147 were higher than those of day 56, and cortisol was higher in heifers than bulls. Final body weight was positively correlated with TSH and T3 and negatively with cortisol concentration. These findings suggest that the inclusion of OC at levels up to 15% in growing/finishing beef diets had no adverse effects on the calves' thyroid and cortical status.

Bunk Space Requirements for Growing Beef Cattle Limit-Fed a High-Energy Corn and Corn Co-Product Diet

Objective: The objective of our experiment was to evaluate the effects of bunk allotment on performance of growing beef calves during a 58-day receiving period and investigate possible residual effects of bunk-space allotment on subsequent growth performance during a 90-day grazing season.

PSIII-5 Predicting live weight using linear body measurements in growing beef calves

Abstract The objective of this study is to investigate how linear body measurements relate to and can be used to predict calf body weight using linear and machine learning models. To meet these objectives, a total of 103 Angus cross calves were enrolled in the study from wk 2 - 8. Calves were weighed and linear measurements were collected weekly, such as: poll to nose, width across the eyes (WE), width across the right ear, neck length, wither height, heart girth (HG), midpiece height (MH), midpiece circumference, midpiece width (MW), midpiece depth (MD), hook height, hook width, pin height, top of pin bones width (PW), width across the ends of pin bones, nose to tail body length, the length between the withers and pins, forearm to hoof, cannon bone to hoof. These measurements were taken using a commercial soft tape measure and calipers. To assess relationships between traits and to fit a model to predict BW, data were analyzed using the Weka (The University of Waikato, New Zealand) software using both linear regression (LR) and random forest (RF) machine learning models. The models were trained using a 10-fold cross-validation approach. The automatically derived LR model used 11 traits to fit the data to weekly BW (r2 = 0.97), where the traits with the highest coefficients were HG, PW and WE. The RF model improved further the BW predictions (r2= 0.98). Additionally, sex differences were examined. Although the BW model continued to fit well (r2 0.97), some of the top linear traits differed. The results of this study suggest that linear models built on linear measurements can accurately estimate body weight in beef calves, and that machine learning can further improve the model fit.

PSXIV-4 Meta-analysis of the effects of monensin on growth and bloat of growing beef calves on pasture

Abstract This meta-analysis investigated the impacts of monensin on performance of stocker cattle on high-forage diets. The stocker performance analysis resulted from 38 experiments with 73 mean comparisons; bloat analysis was conducted with 12 experiments with 23 mean comparisons. The metaphor package (version 2.4-0) for R (version 4.0.3; www.r-project.org) was used to determine the overall effect size of monensin compared to a negative control. Each study’s n, means, and SEM or P-value was used to calculate the mean difference and estimate of within study variance for responses of interest. Moderators of monensin response considered in the analysis were delivery method, dose, study duration, initial calf BW, diet ME and CP, and forage category. Initial BW and basal ADG averaged 236 ± 45.9 kg and 0.72 ± 0.28 kg/day, respectively. In the ADG analysis the only significant moderator of those considered was length of the study (P &amp;lt; 0.01), as duration of the study increased the ADG response to monensin decreased by 0.0007 kg/day. For the average 112-day length of study, the average monensin response is estimated to be 0.0784 kg/day increase in average daily gain. Sufficient information was presented in only 18 citations representing 40 mean comparisons for determining the effect of monensin on BW at the end of the experiment, estimated by (P &amp;lt; 0.01) monensin response (increased ending BW, kg) = 22.3 – 0.05 (initial calf BW, kg). Thus, for the average initial BW of 235 kg the average monensin response is estimated to be 10.6 kg increase in average ending BW. The incidence (-20%) and severity (-0.7 bloat scores) of bloat was found to be reduced in bloat prone pastures. There is ample evidence that monensin increases performance of growing calves on high forage diets along with reducing the incidence and severity of bloat.

Effects of feeding level of alfalfa hay on nitrogen utilization for 1‐kg daily gain of crossbred Simmental male calves

AbstractIn Gansu Province, a key beef cattle production area in China, feeding systems are changing from grazing to stall‐feeding. To reduce production costs, alternative feeding regimens with domestic forages, such as alfalfa hay (AH), are needed. We evaluated the effects of the AH feeding level on nitrogen balance and daily gain (DG) of Simmental calves by two feeding trials. In trial 1, when AH was consumed at 0%–19% of total dry matter intake, no clear effect of AH intake on metabolizable‐protein supply and DG was observed. In trial 2, when more concentrate feed was fed than in trial 1, metabolizable‐protein supply and nitrogen retention increased as the AH consumption rate increased (0%–38% of total intake); these effects appeared to be related to the DG increase. Our results suggest that AH inclusion in concentrate‐based diets increases the metabolizable‐protein supply for the optimal DG of growing beef calves.

Effect of gastrointestinal nematodes on serum copper and phosphorus of growing beef calves in northwestern Argentina.

The aim of this work was to study the effect of gastrointestinal nematodes (GINs) on copper (Cu) and phosphorus (P) in blood of beef cattle in two ranches (R1 and R2) located in northwestern Argentina. In 2015-2016 (R1) and 2016-2017 (R2), in each ranch, 22 weaned female calves were divided into two groups: calves treated systematically with 200mcg/kg moxidectin every 45-50days (TG) and untreated calves (UTG). The following parameters were measured: number of fecal eggs (epg), fecal cultures, serum Cu and P levels, and live weight gain (LWG). Differences between groups were compared using analysis of variance and Tukey test. GIN infections in both ranches were subclinical and moderate, showing the highest epg (R1 = 907 ± 754; R2 = 1049 ± 1040) by mid-winter. Epg values of TG groups were always negligible (> 93% of moxidectin efficacy). The dominant nematode genera were Cooperia and Haemonchus. The average serum Cu values (μg/dl) indicated low (R1 = 49.7 ± 18) and severe (R2 = 27.2 ± 14) deficiency. The effect of treatments was evident in both ranches from late winter, with TG showing significantly (p < 0.01) higher serum levels in winter, spring, and early autumn (R1 = 65.1, 50.9, and 60.3; R2 = 48.0, 25.7, and 22.4) than UTG (R1 = 44.3, 33.9, and 32.9; R2 = 25.5, 18.2, and 16.4). There were no differences in serum P levels between groups. LWG of TG increased significantly (p < 0.008) (27.2% in R1 and 38.6% in R2), with respect to those of UTG. This study showed a negative effect of GIN on serum Cu values in moderately infected growing calves.

Conserved forage-based systems for backgrounding weaned beef calves.

A 45-d backgrounding study was conducted to compare animal performance, forage nutritive value, digestion dynamics, and diet costs of conserved forage systems for weaned beef calves. One hundred and eight weaned Angus × Simmental beef calves (initial BW 279 ± 34 kg) were randomly assigned to one of three diets (n = 3 pens/treatment): 1) free-choice annual ryegrass (RB; cv. ‘Marshall’) baleage and 4 kg of a 50/50 mixture of pelleted soybean hulls and corn gluten feed, 2) free-choice Tifton 85 bermudagrass (BH) and 3 kg of a 50/50 mixture of pelleted soybean hulls and corn gluten feed, or 3) free-choice corn silage (CS; cv. Pioneer P1662YHR) and 2 kg of a 85% cracked corn and 15% cottonseed meal mixture. Diets were formulated to achieve a target gain of 0.9 kg/d based on the NRC (2000) requirement for a 270 kg growing calf. Animal performance (initial BW, final BW, and ADG) was measured on days 0 and 45 of the study. Forage nutritive value and an in vitro digestion trial were conducted to evaluate supplementation effects on forage diet digestion dynamics. Data were analyzed using PROC Mixed in SAS 9.4 as a completely randomized design. Pen was the experimental unit. Mean initial and final BW of the animals did not differ (P = 0.50 and P = 0.99, respectively) across treatments. Calf ADG for RB, BH, and CS diets were 0.61, 0.72, and 0.72 kg/d, respectively, and did not differ across treatments (P = 0.57). Based on these results, these forage options supported a similar level of gain when used for backgrounding beef calves. Forage in vitro DM digestibility differed 48 h after digestion, and BH + 50:50 had greater 48-h digestibility than when unsupplemented, which may be related to complementary forage-supplement interactions. In diets containing RB and CS, digestibility was greater with no supplementation at the 48-h time point. These data support the observation that supplementation type and level influence conserved forage diet digestibility compared with forage alone. The cost of feeding a baleage-based diet in this system was higher ($1.37/d) than CS or BH diets ($1.02 and $0.95/d, respectively). Results suggest that RB baleage-based diets may support a similar level of gain to BH or CS diets in growing beef calves, but supplement type, level, and ration costs should be evaluated when determining cost-effective backgrounding options in the Southeastern United States.

499 Effects of timing of vaccination relative to weaning and post-weaning supplementation frequency on growth and immunity of growing beef calves

A 2 × 2 factorial design study evaluated the impact of pre- vs. post-weaning vaccination associated with different post-weaning frequency of energy supplementation (daily vs. 3x weekly) on growth and immunity of beef calves. At 14 d before weaning, 48 Angus-crossbred calves (24 steers and 24 heifers; 244 ± 33 kg; 196 ± 20 d) were stratified by BW, age, and randomly assigned to receive vaccinations against bovine viral diarrhea virus (BVDV-1a) and parainfluenza-3 (PI-3) on d -14 and 0 (PRE) or 7 and 21 (POS), relative to weaning. Calves were weaned on d 0 and offered daily concentrate DM supplementation at 0.5% of BW for 7 d. On d 7, calves were stratified by vaccination scheme, and assigned into 1 of 16 drylot pens (3 calves of same sex/pen; 4 pens/treatment). Pens were randomly assigned to receive similar weekly concentrate DM supplementation (1% of BW multiplied by 7 d) that was divided and offered daily (7X) or 3 times weekly (3X; Mondays, Wednesdays, and Fridays) until d 43. From d 0 to 43, calves were provided ground tall fescue hay ad libitum (57% TDN, 13% CP of DM) and a concentrate mix of 50:50 soybean hulls and corn gluten feed (71% TDN, 15% CP of DM). Blood samples were collected from jugular vein on d 0, 1, 3, 7, and 14, relative to the respective first vaccination, and on d 43 of the study. Effects of sex and vaccination × supplementation frequency were not detected for any variable in this study (P ≥ 0.12), except for overall ADG from d -14 to 43 (P = 0.04), which was less for PRE3X vs. PRE7X, POS3X, and POS7X calves (0.60, 0.70, 0.70, and 0.77 ± 0.04 kg/d, respectively; P ≤ 0.08). Post-weaning total DMI and G:F did not differ among treatments (P ≥ 0.11). Pre-weaning vaccination increased plasma concentrations of cortisol and haptoglobin from d 0 to 3, relative to first vaccination (P < 0.0001), and decreased serum PI-3 titers on d 42 compared to post-weaning vaccination (P < 0.0001). Decreasing the supplementation frequency tended (P = 0.10) to increase post-vaccination plasma cortisol concentrations and reduce overall serum BVDV-1a titers. Hence, pre-weaning vaccination associated with reduced post-weaning frequency of supplementation caused the least overall calf growth performance. Post-weaning vaccination and daily concentrate supplementation alleviated inflammatory response and improved humoral immune response compared to pre-weaning vaccination and reduced post-weaning supplementation frequency.

Health and growth of Finnish beef calves and the relation to acute phase response

Healthy, thriving calves are essential for beef calf production. We studied the health status and factors associated with the growth of beef calves in six cow-calf herds during the first month of the calves’ lives and at weaning age (200 days).The six herds were visited three times, when calves were approximately 3 days, 16 days and 30 days of age. On each visit calves (n=37) were clinically examined, weighed or measured, blood samples were collected, faecal samples obtained and deep nasopharyngeal swabs were taken. Each blood sample was analysed for acute phase proteins (haptoglobin, serum amyloid-A, fibrinogen), total proteins and albumin, the faecal sample for intestinal tract pathogens (rotavirus, bovine coronavirus, enterotoxigenic Escherichia coli and Salmonella, oocysts of Eimeria coccidia and Cryptosporidium, and nematode eggs), and the nasopharyngeal swab for respiratory tract pathogens (bovine coronavirus (BCV), respiratory syncytial virus (RSV), bacteria and mycoplasma).Clinical diagnosis of respiratory tract disease, diarrhoea or umbilical disease was set at 15.0% for all the three consecutive examinations combined (n=107), but only few pathogens were detected from the samples. The increased levels of acute phase proteins were neither associated with any of the diseases nor with the pathogens. Random intercept linear models were used to explore factors affecting early (3–30 days) and long-term (3–200 days) growth, showing that calves with elevated serum amyloid-A concentrations at the age of 16 days had lower long-term growth. Increased albumin concentration at 30 days of age and higher parity of the dam increased early-term growth. The lack of association between a disease and the acute phase protein may stem from the low disease prevalence in the beef calves examined. The measurement of acute phase proteins of a young calf can help identify animals with possible future growth deficiencies, although the mechanisms through which the association between acute phase proteins and growth has yet to be explained.

Inclusion of anti-phospholipase A2 antibody to backgrounding diets on performance, feed efficiency, in vitro fermentation, and the acute-phase response of growing beef calves.

In Exp. 1, individual performance and daily DMI was measured on 70 crossbred weaned calves during a 70-d period using a GrowSafe system (GrowSafe Systems Ltd., Airdrie, AB, Canada) at the University of Florida North Florida Research and Education Center Feed Efficiency Facility (FEF). Calves were fed a low-concentrate (LC) growing diet, blocked by weight and sex, and then randomly assigned to pens to receive either no additional supplement (CON; n = 35) or receive a supplement of anti-phospholipase A2 antibody (aPLA2) at an inclusion rate of 0.6% of the diet DM (n = 35). After the 70-d feed efficiency (FE) trial (Phase 1), calves were loaded into a commercial livestock trailer and were driven for approximately 1,600 km during 24 h. Upon return to the FEF (Phase 2), calves were relocated to the same pens and groups and received the same diets and treatments for 28 d. Blood samples from each calf were collected on d 0, 1, 3, 5, 7, 14, 21, and 28 relative to initiation of transportation and were analyzed for determination of concentrations of plasma ceruloplasmin and haptoglobin. In Phase 1, initial BW (242.0 ± 3.7 kg; P = 0.92), BW at d 70 (313.0 ± 4.1 kg; P = 0.79), and ADG (1.01 ± 0.02 kg; P = 0.95) were similar between treatments. However, daily DMI was greater (P = 0.01) for CON (9.18 ± 0.15 kg) than aPLA2 (8.53 ± 0.15 kg). In addition, residual feed intake was greater (P = 0.002) for CON (0.389 ± 0.110 kg/d) than aPLA2 calves (-0.272 ± 0.110 kg/d). In Phase 2, after transportation, there were no differences between treatments on BW loss due to transportation shrink (26.0 ± 0.6 kg; P = 0.86), BW at d 28 (339.0 ± 4.1 kg; P = 0.72), ADG (1.28 ± 0.03 kg/d; P = 0.72), G:F (0.164 ± 0.004; P = 0.83), and concentrations of plasma haptoglobin (0.08 ± 0.02 mg/mL; P = 0.41). However, concentrations of plasma ceruloplasmin were greater (P < 0.001) for CON calves (14.3 ± 0.3 mg/dL) compared to aPLA2 calves (13.0 ± 0.3 mg/dL). In Exp. 2, the effects of aPLA2 inclusion on LC and high-concentrate (HC) substrates on in vitro fermentation parameters were assessed. Addition of aPLA2 had no effects on in vitro fermentation parameters of LC and HC substrates. In conclusion, supplementation of aPLA2 improved FE of growing beef calves when fed LC diets in Phase 1 and addition of aPLA2 had no effect on fermentation parameters of LC and HC substrates. In addition, calves supplemented with aPLA2 had reduced concentrations of plasma ceruloplasmin after 24 h of transportation.

Effect of daily or alternate-day distillers grains supplementation with or without monensin on performance of grazing calves

<h2>ABSTRACT</h2> The objective of these experiments was to determine the effect of daily or alternate day supplementation of dried distillers grains with solubles (DDGS) with or without monensin on performance of grazing calves. Treatments included (1) a negative control with no supplemental feed except free-choice mineral; (2) DDGS offered daily at 1.02kg as-fed per calf, including a mineral premix; (3) daily DDGS and monensin (Rumensin, Elanco, Greenfield, IN) at 1.02kg as-fed per calf, including a mineral premix supplying 160mg of monensin/calf daily; (4) alternate day DDGS to supply 2.04kg as-fed per calf, including the mineral premix offered on alternate days; and (5) alternate day DDGS and monensin to supply 2.04kg as-fed per calf, including a mineral premix and 320mg of monensin/calf on alternate days. Four experiments were conducted which included both steers (n=70) and heifers (n=230) grazing warm season grass based pastures (Exp. 1, 2, and 3) or nontoxic endophyte-infected tall fescue (Exp. 4). Supplementation increased ADG (P≤0.04) by 0.16 to 0.26kg/d in the 4 studies, with an average improvement (P<0.01) of 0.21kg/d. Monensin addition and supplement timing had no effect (P≥0.16) on BW, ADG, or supplemental efficiency in any of the 4 experiments. Supplementation increased ADG of growing beef calves regardless of pasture quality or basal cattle performance. The performance improvement was similar whether supplements were fed daily or on alternate days. Contrary to expected results, monensin inclusion in the supplement had no effect on animal performance or supplemental efficiency.

Effects of vaccination on the acute-phase protein response and measures of performance in growing beef calves1

Two experiments were conducted to evaluate the influence of vaccination on the acute-phase protein (APP) reaction (Exp. 1 and 2) and measures of performance (Exp. 2) in growing beef calves. In Exp. 1, the APP reaction was assessed in newly weaned steers administered 1 of 3 treatments (n = 8 steers/treatment), consisting of 1) Mannheimia haemolytica vaccine (One Shot; Pfizer Inc., New York, NY), 2) Clostridium vaccine (UltraBac 7; Pfizer, Inc.), or 3) saline-injected control. Blood samples for the evaluation of APP concentrations were collected on d 0, 1, 3, 5, 7, 10, and 14 and steer BW measured on d 0 and 21 relative to treatment administration. Plasma concentrations of haptoglobin (Hp) increased (P < 0.05) in vaccinated but not control calves and reached a peak on d 3 and 5 for steers receiving Mannheimia haemolytica and Clostridium vaccine, respectively. Plasma concentrations of ceruloplasmin (Cp) and fibrinogen (Fb) increased (P < 0.05) in all calves after treatment administration and Fb concentrations were greatest (P < 0.01) in calves receiving Mannheimia haemolytica vaccine on d 3 and 5 compared with the other treatments. There were no treatment effects (P = 0.44) on 21-d steer ADG (0.43 kg/d; SEM = 0.082). In Exp. 2, 23 heifers were randomly assigned to 2 treatments: 1) vaccinated (Mannheimia haemolytica vaccine (One Shot; n = 12) and 2) saline control (n = 11). After vaccination, blood samples were collected for determination of APP concentrations on d 0, 3, 6, 9, 12, and 15. During this period, individual heifer DMI was measured using an automated feed intake measuring system (Model 4000E; GrowSafe Systems Ltd., Airdrie, Alberta, Canada). Initial and final shrunk BW did not differ (P > 0.36) among treatments. On d 1, plasma Cp concentrations increased (P < 0.01) sharply in vaccinated heifers but not control heifers and were greater (P < 0.05) in vaccinated vs. control heifers on d 3, 6, 9, and 12 relative to injection. Daily DMI did not differ (P = 0.66) among treatments (average = 9.1 kg/d; SEM = 0.34); however, ADG and G:F were greater (P ≤ 0.05) for control vs. vaccinated heifers (1.14 vs. 0.87 kg/d and 0.13 and 0.10 kg, respectively; SEM = 0.064 and 0.011). These data indicate that within a 2 wk period after vaccination, beef calves experience an acute-phase protein response, which may result in reduced ADG and feed efficiency.

Effect of weather patterns on preweaning growth of beef calves in the Northern Great Plains

Records from a 76-year investigation into effects of line breeding and selection of Hereford cattle, and concurrent weather records, were used to assess effects of weather patterns on growth of suckling calves. Calf growth data were adjusted for trends arising from selection and inbreeding, and for effects of age of dam and sex of calf to produce clean estimates of year effects. Daily maximum and minimum temperatures were summarized to identify first and last days of a 1500 growing degree growing season. Precipitation was accumulated from: 1) end of the growing season the previous year through 31 December; 2) 1 January through the beginning of the current year growing season; and 3) during the current growing season. Principal components were used to characterize years. Pre-weaning growth of the calves in sets of eight extreme years identified by each of the principal component was contrasted. Irrespective of precipitation pattern before the growing season and with near or above average precipitation during the growing season, calves reared in years characterized by longer, cooler growing seasons grew faster from birth to weaning than in opposing years. This retrospective analysis indicates a general increase in temperature could decrease growth of suckling calves on the Northern Great Plains of North America.

Evaluation of Tall Fescues for Stocker Cattle in the Gulf Coastal Plain

ABSTRACT New cultivars of nontoxic endophyte-infected (NE) tall fescue must be evaluated under grazing conditions before their commercial release. This research was conducted to compare 2 NE tall fescue cultivars with toxic endophyte-infected Kentucky-31 (KY-31) and an endophyte-free (EF) tall fescue in the Coastal Plain region of southwestern Arkansas. Eleven 0.81-ha pastures were planted to KY-31 (n = 3), EF (cv. Barcel, Barenbrug USA, Tangent, OR; n = 3), or the NE tall fescue cultivars BarOptima, infected with the E-34 endophyte (BarOptima PLUS E-34, Barenbrug USA; n = 3), and Jesup, infected with the AR542 endophyte (MaxQ, Pennington Seed Inc., Madison, GA; n = 2). Pastures were grazed by growing beef calves (n = 33/yr, initial BW = 244 ± 9.5 kg) for 2 yr beginning in January of each year. After 2 grazing seasons, pastures that contained endophyte (KY-31, Jesup AR542, BarOptima PLUS E-34) had greater stand counts than EF (P

Effect of Methionine Source and Level on Performance of Growing Beef Calves Consuming Forage-Based Diets

The effects of level and source of supplemental sulfur-containing amino acids (SAA) on the performance of growing beef calves were evaluated. In Exp. 1, 128 calves (BW = 277 ± 20 kg) were offered supplements containing 0, 2, 4, and 6 g/d of SAA from corn gluten meal (CGM), or 2, 4, 6, or 8 g/d of SAA using 88% 2-hydroxy-4-methylthio butanoic acid (Alimet, Novus International Inc. St. Louis, MO) in liquid molasses slurries for 113 d. Hay was offered as large round bales; supplements were limit-fed at 2.1 kg DM/d. Calf ADG was greater (P < 0.05) for calves supplemented with CGM or 2 and 6 g/d from Alimet than for control calves. Calves provided 2, 4, and 6 g/d of SAA from Alimet and 4 g/d of SAA from CGM had greater (P < 0.05) TDN intake than control calves. In Exp. 2, 72 heifers (BW = 371 ± 3 kg) were assigned to 1 of 3 soybean hull-based supplements that provided 0, 7.5, or 15 g/d of Alimet, which supplied 0, 2.5, or 5.3 g/d of additional SAA. Heifers were offered ad libitum access to water and hay; supplements were limit-fed at 2.3 kg DM/d. Reproductive tract score and pelvic area were measured on d 85. Supplementing 15 g/d of Alimet increased (P < 0.05) ADG during the first 30 d compared with the control diet. Heifers fed 15 g of Alimet daily tended to have greater (P = 0.08) reproductive tract scores. Alimet was effective as a source of supplemental SAA for improving the performance of growing beef calves provided forage-based diets.

Coastal meadows as pastures for beef cattle

The forage yield and quality and the growth of beef calves were examined in a 3-year study on four farms on coastal meadows of the Bothnian Bay, Finland. The forage yield at the end of June (1704 kg dry matter ha −1 in average) was considerably lower than that of cultivated grasslands, whereas the nutritional quality of the forage was approximately at the same level. The daily gain of calves on coastal meadows was 1 kg day −1 on average. The calves raised on the coastal meadows had equal live weights as the beef calves of the same age in northern Finland in general. The interaction between breed and pasture type tended to be significant, indicating that Simmental was capable of slightly better utilisation of coastal meadows than Limousin. Calculation of the nutrient budget showed that the amount of P entering the coastal meadows with creep feeding (0.046 kg ha −1 year −1) constituted a minor proportion of the total P load. Eutrophication of grazed semi-natural grasslands can be most effectively prevented with reasonable usage of additional minerals. The use of a suitable type of livestock and stocking rate and the timing of the grazing season were considered to be important aspects for adjusting the biodiversity management and livestock performance on coastal meadows.

Rice mill feed as a replacement for broiler litter in diets for growing beef cattle.

The efficacy of replacing broiler litter with rice mill feed was evaluated in four experiments. In Exp. 1, 40 predominantly Angus steers (initial BW = 277+/-18.2 kg) were fed four dietary treatments for 112 d (five steers per pen; two pens per diet). Dietary treatments (DM basis) were as follows: 1) 47% broiler litter:53% corn; 2) 60% rice mill feed:40% corn; 3) 50% rice mill feed:50% corn; and 4) 40% rice mill feed:60% corn. All diets, along with bermudagrass hay, were fed free choice. Daily gains were faster (P < 0.10) for the 50:50 and 40:60 diets (1.26 and 1.30 kg/d, respectively) than for the broiler litter diet (0.89 kg/d). Daily DMI was less (P < 0.10) by steers consuming rice mill feed-based diets than by those consuming broiler litter-based diets. In Exp. 2, 16 Angus x Charolais steers (initial BW = 277+/-22.7 kg) were fed the same four diets used in Exp. 1 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was not different (P > 0.10) among diets. Nutrient digestibilities did not differ among diets (P > 0.10). In Exp. 3, 40 Continental cross steers (initial BW = 257+/-21.3 kg) were fed one of four dietary treatments for 112 d (five steers per pen; two pens per diet). On a DM basis, diets were as follows: 1) 47% broiler litter:53% soyhulls; 2) 70% rice mill feed:30% soyhulls; 3) 60% rice mill feed:40% soyhulls; and 4) 50% rice mill feed:50% soyhulls. All diets, along with bermudagrass hay, were fed free choice. Daily gains were less (P < 0.05) for the broiler litter diet than for the 60:40 and 50:50 diets (1.05, 1.16, and 1.28 kg/d, respectively), and steers fed the broiler litter diet consumed less DM than did steers fed the varying rice mill feed-based diets (P < 0.10). In Exp. 4, 16 Angus x Charolais steers (initial BW = 292+/-21.1 kg) were fed the same four diets as in Exp. 3 while housed in individual metabolism stalls for determination of nutrient digestibility. Daily DMI was less (P < 0.01) for the broiler litter diet (5.0 kg/d) than for the 70:30, 60:40, and 50:50 diets (7.8, 7.9, and 7.9 kg/ d, respectively). Digestibilities for DM, OM, and ADF did not differ (P > 0.10) among treatments; however, CP digestibility was greatest (P < 0.10) for the 60:40 diet, and NDF digestibility was least (P < 0.10) for the 70:30 diet. Rice mill feed can be used to replace broiler litter to formulate low-cost diets for stocker calves. Soyhulls and corn can be blended with rice mill feed to produce acceptable backgrounding diets for growing beef calves.

Amino acid and energy interrelationships in growing beef steers: II. Effects of energy intake and metabolizable lysine supply on growth.

We conducted three experiments to determine the optimal metabolizable Lys:net energy ratio for growth of beef calves. The single basal diet fed contained corn (56.1%), soybean hulls (18%), cottonseed hulls (15%), animal fat (4.25%), and corn gluten meal (5.6%). In Exp. 1, 54 steers were individually fed the basal diet at 1.5, 2.25, and 3.0 times NEm requirement; rations were top-dressed with 3.4 g of rumen-stable (RS) Met and either 0, 2, 4, 6, 8, or 12 g of RS-Lys daily. An additional 18 steers were fed the same three levels of energy and supplemented with 125 g of blood meal per steer. In Exp. 2, 68 crossbred steers were subjected to the same experimental protocol, with the exception that only the two highest levels of energy were used. Of these steers, 48 were fed individually and received the RS-Lys treatments; the remaining 20 steers received 125 g of blood meal per steer. No interaction (P > .10) was detected between level of supplemental Lys and energy intake in Exp. 1 or 2. Supplementation with RS-Lys improved (P < .01) ADG in Exp. 1, but it had no effect (P > .10) on growth in Exp. 2. The Lys requirement estimates were 44.3 and 51.3 g/d, corresponding to maximal growth rates of 1.21 and 1.64 kg/d for the 2.25 and 3.0 times maintenance treatments, respectively. Comparing the growth rates of steers fed supplemental Lys with those of steers fed blood meal in Exp. 1 and 2 revealed an ADG advantage (P < .03) with blood meal supplementation. To confirm the blood meal response, Exp. 3 used 75 crossbred steers fed the basal diet at 3.0 times NEm requirement plus either 3.4 g RS-Met, 3.4 g RS-Met and 12 g RS-Lys, or 125 g of blood meal per steer. Blood meal supplementation improved (P < .01) growth of steers over those fed supplemental Met or Met plus Lys. Although a distinct relationship between amino acid requirements and energy supply may exist, Lys and Met were not first-limiting in these experiments, or selective supplementation with undegradable protein may have provided some factor that enhanced performance beyond that detected with Lys and Met alone.

Effect of fungal biomass in alfalfa hay on intake and total tract digestion in growing beef calves.

Two experiments were conducted to determine effects of fungal biomass (FB), as determined by glucosamine analysis, in alfalfa hay on intake and total tract digestion when fed to growing beef calves. Mycotoxins were not detected in hays used for these experiments. A feedlot trial using 40 weaned Angus calves (270.2 +/- 9.7 kg) showed that DM intake was not affected (P > .05) by FB content of the hay diets. No adaptation response was observed when animals with no previous exposure to molded feed were introduced to hay containing various levels of FB. Hematocrit and plasma cortisol levels were not affected (P > .05) by the presence of FB in the hay. Eight steers were used, in two 4 x 4 Latin squares, for intake and total tract digestibility determinations of two alfalfa hays having similar nutrient profiles but differ in FB concentrations. Hays were fed in long or chopped form. Level of FB did not affect (P > .05) DM intake or total tract DM digestibility. Neutral detergent fiber and ADF digestibilities were 5.4 and 3.7 percentage units higher (P < .05), respectively, for hay with a high vs low FB concentration. Forage chopping reduced (P < .05) DM, NDF, ADF, and CP digestibilities; the effect being similar for the two hay types tested. Results suggest that FB concentrations ranging from 2.9 to 5.5 mg/g of DM do not affect DM intake, however, nutrient digestion can be influenced by molding during field wilting or storage.