Donald A. Llewellyn

Effect of adding Aureomycin® for anaplasmosis control or Rumensin® to mineral supplements on summer beef cowherd performance

Two hundred forty-six commercial Angusbased cows were used to determine the effect of adding Aureomycin for anaplasmosis control or Rumensin to mineral supplements on summer beef cowherd performance. Cow/calf pairs were randomly allotted to summer native-pasture groups by treatment, and were fed an industry-standard mineral/trace mineral supplement for the duration of the trial. The study had three treatments: (1) control mineral supplement with no medication added, (2) the same base supplement with the addition of Aureomycin (0.5 mg/lb cow body weight daily), and (3) the base supplement with the addition of Rumensin (200 mg/cow daily). Feed additives were blended into the mineral mix to provide the targeted daily consumption. Treatments were initiated May 6 and maintained through October 6. Mineral intake was similar among treatments. Cow and calf weight gains were similar among treatments during the first 32 days of the study. By the trial end, there were no significant differences in cow body condition score gains and pregnancy rates. Total calf gains for the duration of the trial were similar for groups supplemented with Aureomycin, and Rumensin, and both were greater than for control calves (21 and 18 lb greater, respectively). Overall herd health was enhanced by feeding Aureomycin when compared with control or Rumensin. Foot rot was the main health concern in this trial, and the addition of Aureomycin to mineral supplements reduced foot rot. Introduction

Performance of calves born to beef cows seropositive but subclinical for bovine leukosis virus

Calves from a commercial beef herd were evaluated for weight gain differences based upon the bovine leukosis virus (BLV) serological status of their dams. One hundred forty-two multiparous cows from a commercial beef herd were tested for BLV by agar gel immunodiffusion. Eighty-nine cows (62.6%) were found to be seropositive for BLV. Weights were collected from all calves at weaning, from heifers on the date when selection of replacement heifers was made, and from steers on the day of harvest after being fed to finish weight in a feedlot. Offspring from seronegative cows tended to have heavier weaning weights (+17 lb) and heifer selection weights (+31 lb) than those from seropositive cows.

Comparison of corn and grain sorghum dried distillers grains as protein supplements for growing beef heifers

An experiment was conducted to determine if corn and grain sorghum dried distillers grains could be effective protein supplements for growing beef replacement heifers. Crossbred heifers (n=77) were individually fed 6 lb/heifer daily (dry matter basis) of supplements containing 20% crude protein. The three supplements compared were: 1) 50% cracked corn, 25% soybean meal, and 25% ground grain sorghum; 2) 50% cracked corn and 50% corn distillers grains with solubles; and 3) 50% cracked corn, 31% sorghum distillers grains with solubles, and 19% ground grain sorghum. Heifers grazed a common native-grass pasture and had free-choice access to smooth broom hay in round bale feeders. During the last week of the trial, heifers (n=4) from each supplement were used to determine diet digestibility. Although there were no differences in weight gain or total diet digestibility, dry matter intake as a percentage of body weight was less for heifers receiving supplements containing dried distillers grains from either corn or grain sorghum. Our data indicate that producers can expect similar growth performance, regardless of the grain source of dried distillers grains used to formulate a 20% crude protein supplement fed at about 1% of body weight daily.

Influence of early weaning and winter protein supplementation on weight and condition score of spring-calving beef cows grazing native tallgrass prairie

Ninety-two pregnant, mature, spring-calving cows grazing low-quality tallgrass-prairie were used to determine if early weaning of calves reduces the supplementation cost during the subsequent winter. Calves were weaned on June 23, 2003, (early weaning) or October 15, 2003, (fall weaning). Cows were assigned to winter feeding groups and fed one of two amounts of a common soybean meal-milo supplement (45% crude protein; dry matter basis). The two supplementation amounts were fed three times weekly and were prorated to 4 lb/day and 2.8 lb/day. The four treatment groups were: 1) early weaning 4 lb/day supplement, 2) early weaning 2.8 lb/day supplement, 3) fall weaning 4 lb/day supplement, and 4) fall weaning 2.8 lb/day supplement. Cows were supplemented from November 14, 2003, through calving in early March 2004. Cows with calves weaned early were initially heavier and had higher initial body condition scores than did cows that were weaned in the fall. Although losses of body weight and body condition through the winter were greater for early-weaning cows than for fall-weaning cows, final body weights and body condition scores were still greater for the early-weaning cows than for the fall-weaning cows. Supplementation with 4 lb/day led to less body weight loss over the winter and heavier final body weights than did supplementation with 2.8 lb/day, but final body condition score and body condition score loss over the winter were not affected by the amount of winter supplementation. Cow-calf producers can balance responses to early weaning and to winter supplementation to target appropriate cow weights and body condition scores at calving.

Influence of fall protein supplementation with a self-fed liquid supplement on performance of beef cows grazing tallgrassprairie range

We evaluated the effect of providing a liquid, high-protein supplement during the fall grazing period on beef cow and calf performance. Mature, pregnant, spring-calving cows (n=122) grazing native range were assigned to supplementation treatments. All calves were weaned on October 15. Control cows received no fall supplementation and then were handfed a dry supplement (40% crude protein; asfed basis) from December 17 until calving. Supplemented cows were either allowed access to a liquid protein supplement (40% crude protein; as-fed basis) approximately 2 months before weaning until calving (fall supplementation from August 14 to December 17) or from weaning until calving (fall supplementation from October 15 to December 17). Supplement intake of the control cows from December 17 until calving was adjusted to match the estimated supplement intake of the liquid-fed groups and was prorated and fed 3 days/week. Supplementation was terminated upon calving, at which time all cows were treated similarly. Provision of liquid supplement during the fall increased cow body weight and body condition in the postweaning period. However, cows not supplemented during the fall phase were able to overcome their lesser previous nutrition when they were suitably supplemented during the winter phase. The pre-weaning rate of gain of calves was not affected by fall supplementation. Calves produced by cows receiving no fall supplementation gained more weight from birth to the start of the summer grazing season. Subsequent pregnancy rate was not affected by fall supplementation.

Failure to eliminate the carrier state of Anaplasma marginale by using long-acting injectable oxytetracycline

Thirty-four Anaplasma marginale seropositive cows from a herd of 236 were allocated to treatments: 5 animals served as untreated controls, and 29 animals were treated with three injections of long-acting oxytetracycline at three-day intervals. Fourteen days after initiation of treatment, 100% of control cows and 89% of treated cows were found to have Anaplasma marginale present. Seventyfour days after initiation of treatment, 100% of control cows and 86% of treated cows were found to have Anaplasma marginale present. Use of injectable long-acting oxytetracycline was not effective in eliminating the carrier state of Anaplasma marginale from infected animals.

Effects of route of administration of a commercially available Mannheimia (pasteurella) haemolytica vaccine on titer levels

One hundred thirteen Hereford x Angus heifer calves (average weight = 515 lb) were allotted to one of three treatments: 1) control, no vaccine; 2) a 2-cc subcutaneous injection of One-Shot (Pfizer Animal Health), a Mannheimia (pasteurella) haemolytica vaccine, three weeks before weaning; or 3) a 1⁄2-cc intradermal injection of One-Shot, three weeks before weaning. All heifers were weighed and blood samples harvested at time of injection, three weeks later at weaning, and then 28 days later. After weaning, heifers were confined to a common pen and fed freechoice brome hay and approximately 5 lb/head daily of a concentrate. Blood samples from 30 heifers were shipped to a laboratory for titer analysis. No differences were found in animal performance and sickness during the preconditioning period. Heifers injected by the subcutaneous route had greater increases in whole-cell and leukotoxin-neutralizing antibody titer levels than the intradermal or control treatments. These data suggest that beef producers should follow label recommendations for dosage and route of administration to maximize vaccine efficacy. Introduction

Influence of low-level fall protein supplementation on forage intake, diet digestion, and selection by beef steers grazing tallgrass-prairie range

This study evaluated the effect on forage utilization of providing a limited quantity of a high-protein (40% crude protein) supplement to beef cattle grazing tallgrass prairie during the fall. Sixteen ruminally fistulated beef steers were randomly assigned to one of two treatments (fall supplementation or no fall supplementation), which were evaluated for their effect on forage intake and digestion during September and November. Within each treatment, four steers were used for measuring diet selection (by ruminal evacuation) and four were used for determining diet digestion (by total fecal collection). Data from both groups were used to calculate forage intake. Steers were individually fed a high-protein supplement at a rate of 0.14% of body weight/day (as-fed basis; 0.80 lb/day during September and 0.99 lb/day during November) but prorated and delivered only three days per week. Quality of diet selected decreased as season progressed (decreased protein and increased fiber) and, as a result, forage intake and digestion was significantly lower during the late fall period. Neither diet selection nor forage intake were significantly influenced by fall supplementation; however, supplemented steers digested their total diet to a greater extent.

Effect of supplemental carbohydrate type and amount of ruminally degradable protein on utilization of tallgrass-prairie hay by beef steers

This experiment determined the impact of type of supplemental carbohydrate and amount of supplemental ruminally degradable protein (RDP) on intake and digestion of prairie hay. Fourteen ruminally fistulated beef steers were supplemented with one of two carbohydrates (corn starch or the simple sugar glucose) at 0.30% of body weight and one of seven levels of ruminally degradable protein (RDP; 0, 0.015, 0.051, 0.087, 0.123, 0.159, or 0.195% of body weight). Two additional steers served as controls (non-supplemented steers, i.e., no carbohydrate or RDP supplementation). Forage intake and digestion were substantially improved by increasing amounts of supplemental RDP. Supplemental carbohydrate with insufficient supplemental RDP depressed fiber digestion although carbohydrate type did not alter the digestion response or forage intake. In conclusion, when supplementing cattle eating low-quality forage, it is important to ensure that the supplement contains adequate RDP. The impact of the supplement on forage use should not differ greatly between starch (e.g., cereal grains) and sugar (e.g., molasses) as the main carbohydrate source.

Effects of castration age and a growth implant during suckling on weaning and preconditioned weights

Crossbred Angus calves (n=141) were used to determine the effect of castration age and implant on weaning and preconditioned weights. Calf treatments consisted of: early castration at 90 days of age with no growth implant, early castration with a growth implant (Synovex C) at 90 days of age, or late castration at weaning (226 days of age). All calves completed a preconditioning program that consisted of timely vaccinations (21 days prior and at weaning) and a 28-day, postweaning feeding period. Steers that were early castrated/implanted had weaning weights similar to those of bull calves, and both groups weighed 15 lb more than their early castrated/no implant contemporaries. However, 28 days after weaning the early castrated/implanted steers weighed 20 lb more than either the early castrate/no implant or late castrated steers. Our data indicate that early castration in combination with a suckling phase implant produces the greatest amount of saleable weight along with the most flexibility in marketing options.