Predicting feed intake in confined beef cows.

Six existing equations (three for nonlactating and three for lactating; NRC, 1987, Predicting feed intake of food-producing animals. Washington, DC: The National Academies Press, National Academy of Science; doi: 10.17226/950; NRC, 1996, Nutrient requirements of beef cattle, 7th Revised Edition: Update 1996.

Effects of adding ruminal propionate on dry matter intake and glucose metabolism in steers fed a finishing ration.

The objective of this experiment was to determine if supplying additional propionate to the rumen alters dry matter intake (DMI), feeding behavior, glucose metabolism, and rumen fluid metabolites in steers fed a finishing diet. Ruminally cannulated steers (n = 6) were fed a finishing diet ad libitum. Steers were randomly assigned to one of three treatments in a 3 × 6 Latin rectangle design with three 15 d periods.

The Effects of Respiratory Vaccine Type and Timing on Antibody Titers, Immunoglobulins, and Growth Performance in Pre- and Post-Weaned Beef Calves.

In order to examine the effects of vaccine type and timing of crossbred beef calves ( = 151) were assigned to one of three BRD vaccination protocols stratified by breed of sire, sex, and date of birth, which included: (1) KM-a pentavalent killed viral (KV) vaccine at 2 to 3 months of age (D 0) and a pentavalent modified-live viral (MLV) vaccine at weaning (D 127); (2) MM-MLV on D 0 and revaccinated on D 127 or (3) WN-MLV at weaning and D 140. Vaccination treatment did not affect performance nor BRSV serum-neutralizing antibody titers. Serum-neutralizing antibody titers to BVDV-1 were greatest for the MM through D 154.

Effects of diet on feed intake, weight change, and gas emissions in beef cows.

The objective of this study was to examine the effects of diet energy density on ranking for dry matter intake (DMI), residual feed intake (RFI), and greenhouse gas emissions. Forty-two mature, gestating Angus cows (600 ± 69 kg body weight [BW]; body condition score [BCS] 5.3 ± 1.

Meta-analysis of the effects of monensin on performance of beef replacement heifers and beef cows.

Although performance benefits of monensin have been extensively studied in finishing cattle, growing cattle, and dairy cows, considerably less published work is available evaluating response to monensin supplementation in cow-calf production systems. This meta-analysis investigated the impacts of monensin on performance of beef cows and developing replacement heifers. The replacement heifer analysis was conducted using data from 18 different peer-reviewed publications and experiment station reports.

Meta-analysis of the effects of monensin on growth and bloat of cattle on pasture.

Monensin has been part of the beef production landscape for over 45 years. Although first approved for use in finishing cattle, it has since been approved for cattle in extensive production systems and has been an economical way to increase performance of forage-fed animals. This meta-analysis investigated the impacts of monensin on performance of stocker cattle on high-forage diets.

Effects of supplementation rate of an extruded dried distillers' grains cube fed to growing heifers on voluntary intake and digestibility of bermudagrass hay.

Our objectives were to 1) investigate the difference in chemical composition and disappearance kinetics between loose dried distillers' grains (DDG) and extruded DDG cubes and 2) evaluate the effects of supplementation rate of extruded DDG cubes on voluntary dry matter intake (DMI), rate and extent of digestibility, and blood parameters of growing beef heifers offered ad libitum bermudagrass (Cynodon dactylon) hay. To characterize the changes in chemical composition during the extrusion process, loose and extruded DDG were evaluated via near-infrared reflectance spectroscopy, and dry matter (DM) disappearance kinetics were evaluated via time point in situ incubations. Extruded DDG cubes had greater (P ≤ 0.

Effects of increasing calcium propionate in a finishing diet on dry matter intake and glucose metabolism in steers.

The objective of this study was to determine whether increasing propionate alters dry matter intake (DMI), glucose clearance rate, blood metabolites, insulin concentrations, and hepatic gene expression in steers fed a finishing diet. Holstein steers (n = 15; BW = 243 ± 3.6 kg) were individually fed a finishing diet ad libitum.

Water and forage intake, diet digestibility, and blood parameters of beef cows and heifers consuming water with varying concentrations of total dissolved salts.

The objective of this study was to investigate the effects of water quality on water intake (WI), forage intake, diet digestibility, and blood constituents in beef cows and growing beef heifers. This was a replicated 5 × 5 Latin square with five drinking water treatments within each square: 1) fresh water (Control); 2) brackish water (100 BRW treatment) with approximately 6,000 mg/kg total dissolved solids (TDS); 3) same TDS level as 100 BRW achieved by addition of NaCl to fresh water (100 SLW); 4) 50% brackish water and 50% fresh water to achieve approximately 3,000 mg/kg TDS (50 BRW); and 5) same TDS level as 50 BRW achieved by addition of NaCl to fresh water (50 SLW). Each of the five 21-d periods consisted of 14 d of adaptation and 5 d of data collection.

Effects of bale feeder design on hay waste, intake, and apparent diet digestibility in gestating beef cows.

Two experiments were conducted to determine the effects of feeder design on hay intake, apparent diet digestibility, and hay waste in gestating beef cows. Native tallgrass prairie hay and a protein supplement was fed throughout both experiments. In Exp.

Maintenance energy requirements and forage intake of purebred vs. crossbred beef cows.

The objective of this study was to investigate the impacts of cow breed type and age on maintenance requirements, feed energy utilization, and voluntary forage intake. The main effect of breed type included Angus (ANG; = 32) and Hereford × Angus (HA; = 27) lactating cows. The main effect of age included 2- and 3-yr-old (YOUNG; = 29) and 4- to 8-yr-old (MATURE; = 30) cows.

Application of the California Net Energy System to grazed forage: feed values and requirements.

The California Net Energy System (CNES) has been successfully used for many years to generate estimates of grazing animal energy requirements, supplemental needs, and energy value of grazed forage diets. Compared to pen feeding situations, validation of feed nutritive value estimates or animal performance projections are extremely difficult in grazing animals because many of the system inputs are constantly changing. A major difficulty in applying this or any energy accounting system in the field is acquiring accurate estimates of forage intake.

Effects of timing of weaning on energy utilization in primiparous beef cows and post-weaning performance of their progeny1.

Early weaning is used to minimize cow nutrient requirements in situations where feed inputs are scarce or expensive. For many years, maintenance energy requirements have been assumed to be 20% greater in lactating compared with non-lactating beef cows. While not well established, maintenance energy requirements are thought to be greatest in primiparous cows and to decline with age.

In vivo ruminal degradation characteristics and apparent digestibility of low-quality prairie hay for steers consuming monensin and Optimase.

Seven ruminally cannulated crossbred steers (BW = 720 ± 62 kg) were used in a randomized crossover design (4 periods, each 18 d) to evaluate in vivo rumen characteristics and apparent digestibility of steers consuming low-quality prairie hay and 1 of 4 isonitrogenous protein supplements. Treatments included 1) 40% CP (DM basis) cottonseed meal and wheat middlings-based supplement (Control), 2) a cottonseed meal and wheat middlings-based supplement with slow-release urea and a fibrolytic feed enzyme (Optimase; Alltech, Inc., Nicholasville, KY) designed to replace 30% of plant-based CP provided in the Control (OPT), 3) the Control plus 0.

Technical note: Digital quantification of eye pigmentation of cattle with white faces.

Cancer of the eye in cattle with white faces occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation is related to eyelid pigmentation and occurrence of lesions that may precede cancer. Objectives of this study were to assess 1) variation in the proportion of eyelid and corneoscleral pigmentation in Hereford, Bos taurus, and Bos indicus crossbreds and 2) the occurrence of lesions with the presence of pigmentation in those areas.

Supplementation of monensin and Optimase to beef cows consuming low-quality forage during late gestation and early lactation.

Two experiments were designed to investigate the effects of feeding monensin and/or slow release urea with a fibrolytic feed enzyme (Optimase; Alltech, Inc., Nicholasville, KY) on performance, milk production, calf growth performance, and blood metabolites in beef cows. Spring-calving cows and heifers were used in a completely randomized design in Exp.

Supplementation of dried distillers grains with solubles to beef cows consuming low-quality forage during late gestation and early lactation.

Three experiments were conducted to evaluate supplementation of dried distillers grains with solubles (DGS) to spring-calving beef cows (n = 120; 541 kg of initial BW; 5.1 initial BCS) consuming low-quality forage during late gestation and early lactation. Supplemental treatments included (DM basis) 1) 0.

Effect of muscle type, sire breed, and time of weaning on fatty acid composition of finishing steers.

Thirty-three steer calves were used to determine the effect of sire breed (Angus or Charolais), time of weaning [normal weaned at approximately 210 d of age (NW) or late weaned at approximately 300 d of age (LW)], and muscle type [LM and semitendinosus muscle (STN)] on fatty acid composition. The whole plot consisted of a 2 (sire breed) × 2 (time of weaning) treatment arrangement, and the subplot treatment was muscle type. Body weights were recorded at 28-d intervals to determine animal performance.

Effects of prepartum supplementation of linoleic and mid-oleic sunflower seed on cow performance, cow reproduction, and calf performance from birth through slaughter, and effects on intake and digestion in steers.

Two experiments were conducted to determine the effects of sunflower seed supplements with varying fatty acid profiles on performance, reproduction, intake, and digestion in beef cattle. In Exp. 1, 127 multiparous spring-calving beef cows with free-choice access to bermudagrass hay were individually fed 1 of 3 supplements for an average of 83 d during mid to late gestation.

Effect of weaning date (normal vs. late) on performance of young and mature beef cows and their progeny in a fall calving system in the Southern Great Plains.

Data from 158 predominantly Angus fall-calving beef cows were used in 4 consecutive years to determine the effects of weaning date and cow age class on cow and calf performance. Treatments were arranged in a 2 x 2 factorial with 2 weaning dates and 2 age classes (young cows or=4 yr). Weaning dates were 1) normal weaning in mid-April at 210 d of age (NW) and 2) late weaning in mid-July at 300 d of age (LW).

In situ ruminal degradation characteristics of by-product feedstuffs for beef cattle consuming low-quality forage.

Eight ruminally cannulated steers (BW = 753 +/- 48 kg) were used to evaluate in situ N, NDF, and DM degradation characteristics of by-product feeds and their application for beef cows consuming low-quality forage. Experimental feedstuffs included (DM basis) 1) extruded-expelled cottonseed meal (ECSM; 33% CP and 55% NDF), 2) extruded-expelled cottonseed meal with linters (ECSML; 25% CP and 41% NDF), 3) dried distillers grains with solubles (DGS; 33% CP and 36% NDF), 4) solvent-extracted cottonseed meal (CSM; 43% CP and 29% NDF), and 5) a blend of 76% wheat middlings with 18% CSM (WMCSM; 23% CP and 40% NDF). Steers were fed chopped prairie hay (4.

Supplemental energy and extruded-expelled cottonseed meal as a supplemental protein source for beef cows consuming low-quality forage.

Three experiments were conducted to evaluate the efficacy of supplemental energy and extruded-expelled cottonseed meal (ECSM; 30.6% CP; 44% NDF, 10.2% fat; DM basis) as a protein supplement (SUP) to spring-calving beef cows (n = 96; 535 kg initial BW; 5.

Effects of body condition score at parturition and postpartum protein supplementation on estrous behavior and size of the dominant follicle in beef cows.

The objective of this study was to determine the effects of BCS at calving and the amount of postpartum protein supplementation on the dominant follicle (DF) and behavioral characteristics at the first postpartum estrus of mature beef cows. Multiparous Angus x Hereford cows (n = 45) were fed to calve in thin (T; < 5) or moderate (M; >or=5) BCS. Cows were stratified by BCS and calving date, and randomly assigned to receive lesser (L; 1.