J.M. Phillips

Development of Replacement Heifers Using Programmed Feeding1

This experiment was conducted to determine the effects of diet and pattern of gain on reproductive performance. On November 24, 80 spring-born Angus- and Brangus-sired heifers (BW = 230 ± 23 kg) were allotted by breed and BW to one of four treatments (two replicates per treatment). Heifers were program-fed to gain 0.68 kg/d until April 14 (134 d, MODERATE ), grazed wheat (cv. Hickory, Triticum aestivum L.) and ryegrass (cv. Marshall, Lolium multiflorum Lam.) interseeded into bermudagrass pasture ( GRAZED ), or were program-fed to gain 0.23 kg/d until February 4 (71 d) and then program-fed to gain 0.91 kg/ d (63 d, SLOW-FAST ) or grazed wheat and ryegrass pastures ( SLOW-GRAZED ). On February 4, MODERATE heifers were heavier (P 0.70) among treatments. Pregnancy rate tended to be less (P=0.16), conception date was later (P SUN ) tended to be greater (P=0.14) for GRAZED and SLOW-GRAZED heifers than for MODERATE and SLOW-FAST heifers. Program feeding can be a valuable tool for developing replacement heifers as long as BW goals pre-breeding are reached. Grazing heifers on cool-season annuals during breeding may impair reproduction as a result of the high forage N concentrations, causing reduced fertility.

Effects of Diet Fed During Backgrounding in Drylot on Ruminal Function of Cattle During Adaptation to Pasture1

This experiment was conducted to determine the effects of type of diet fed in drylot on the changes in the ruminal environment and in situ forage DM disappearance during adaptation from drylot diet to vegetative pasture. Sixteen ruminally cannulated steers were used in a randomized complete block experiment (BW = 535 ± 3.6 kg in Block 1 and 333 ± 3.2 kg in Block 2). Eight steers were assigned to four treatments in each block: ad libitum bermudagrass hay with either a dry supplement (DS) or a molasses-based supplement (MBS) or limit-fed a high-concentrate diet with either a dryprotein supplement (LFDS) or molassesbased protein supplement (LFMBS). Ken

Season-Long vs Intensive-Early Stocking with Growing Cattle Grazing Bermudagrass Pasture

Abstract Our objective was to compare the performance of weaned steer calves managed with intensive-early stocking (IES; 12.4 steers per ha for 70 d) or season-long stocking (SLS; 6.2 steers per ha for 140 d) with and without supplementation (2 x 2 factorial). Beginning on May 15, 90 steers (BW = 217 ± 0.8 kg) were randomly assigned to one of 12 common bermudagrass (Cynodon dactylon [L.] Pers.) pastures (0.81 ha each) fertilized with 168 kg of nitrogen/ ha. One of the following four treatments was randomly applied to three pastures: i) SLS plus no supplement, ii) SLS plus 0.45 kg/steer of ground corn daily, iii) IES plus no supplement, and iv) IES plus 0.45 kg/steer of ground corn daily. Steers on IES were lighter (P=0.01) than SLS steers on d 70. By d 140, SLS steers supplemented with corn were 33 kg heavier (P=0.02) than nonsupplemented steers. When using SLS, corn increased the BW gain 0.5 kg/kg of corn fed; however, when IES was used, there was no benefit from corn supplementation. Total BW gain/ha did not differ (P>0.17) among treatments, but SLS with corn supplementation could have the potential to produce more BW gain/ ha compared to the other treatments. Grazing systems did not affect feedlot ADG (P>0.53), but IES (175 d on feed) steers did have a higher (P

Change in hoof phosphorus content for bulls in a 112-day postweaning feedlot performance test

Abstract Hoof samples for mineral analysis from four breed groups of bulls—Angus (n=20), Brangus (n=19), Hereford (n=31) and Simmental (n=53)—obtained during a 112-d postweaning feedlot performance test were used to study effects on the change in hoof phosphorus (P) concentrations. Hoof samples were obtained for mineral analysis from the right front foot of all bulls on d 1 and 112 of four tests conducted in three locations in Arkansas. Data were analyzed using least-squares analysis of variance. The model included terms for common element, an effect due to test, breed, farm of origin within breed, hoof pigment, initial age and residual error. Breed means were separated using repeated t-test. Residual correlations between P and other hoof minerals were obtained. Breed was the only significant source of variation on the change in hoof P. The model explained 45% of the variation (R 2 ). Breed means for the change in P showed both Angus and Brangus bulls significantly different ( P P P

Effects of Diet Fed in Drylot on Subsequent Grazing Performance of Growing Cattle1

Two experiments were conducted to determine the effects of diet and rate of BW gain in drylot before grazing on subsequent grazing performance. In Experiment 1, 154 calves (initial BW ± SE = 181 ± 1.98 kg) were fed bermudagrass (Cynodon dactylon (L.) Pers.) hay or were program-fed for an ADG of 0.23, 0.57, or 0.91 kg/d. In Experiment 2, 96 calves (initial BW ± SE = 211 ± 1.63 kg) were fed bermudagrass hay with either a dry (DS) or a molasses-based supplement (MBS) or were program-fed a diet containing either a dry (PFD) or molasses- based (PFM) supplement (2 × 2 factorial). Regression analysis of grazing performance during Experiment 1 suggested that pasture ADG was reduced by 0.10 kg for every kilogram increase in gain during the feeding period (P<0.01; r2 = 0.13). During the first 41 d of grazing small grains or tall fescue, calves program fed in drylot gained 0.31 kg/d (P<0.01) or tended (P=0.07) to gain 0.26 kg/d, respectively, more than calves fed hay in drylot. In Experiment 2, during the first 14 d of the grazing period, program-fed calves (PFD and PFM) gained 0.74 kg/d more (P<0.01) than calves fed hay-based diets (DS or MBS), and calves on the MBS and PMBS treatments gained 0.23 kg/d more (P=0.01) than calves on the DS and PFD treatments. Program feeding is an economical alternative to feeding calves hay and supplement, and diet fed in drylot can influence performance of calves adapting to high quality pasture.

Prevalence of Mastitis Pathogens Preceding and Following Parturition in Primiparous Beef Cows

Abstract Prevalence of intramammary infection was studied in primiparous beef cows preceding and following parturition. Aseptic mammary quarter samples were collected from Brahman-sired cows (Group 1; n = 19) on d −143, −30, and 110 ± 4 from parturition, and from Angus-sired cows (Group 2; n = 54) on d -36 and 37 ± 2 from parturition. In Group 1, 67.6, 55.6, and 9.3% of quarters sampled were infected with mastitis pathogens on d −143, −30, and 110 ± 4 from parturition, respectively. In Group 2, 35.3 and 10.4% of the quarters were infected on d −36 and 37 ± 2 from parturition, respectively. In Group 2, over 22% of the quarters that had previously been infected with Staphylococcus aureus, and over 26% of the quarters that had previously been infected with Staphylococcus species were still infected with the same organism on d 37 ± 2 postpartum. In Group 2, representative cows were selected for blood chemistry analyses (n = 30) and machine milking (n = 46). Serum potassium was higher (4.64 vs 4.36 ± 0.09 mmol/L; P

Weaning Rate of Brangus and Brahman × Hereford F1 Cows Under Intensive Grazing Management1,2

Weaning rate of Brangus (BG) and Brahman x Hereford F1, (HBR) cows on either Tifton 44 hybrid bermudagrass (T44HB) or common bermudagrass-dallisgrass (CBD) was studied. Simmental-sired calves were born in February-March the following year from each breeding season May 1 to June 30 of years 1987, 1988, 1989, and 1990. An intensive rotational grazing system with 30 cows on 9.6 ha was used. Each of four 9.6-ha pastures (two of each forage) contained 15 BG and 15 HBR cows. The 9.6-ha pastures were subdivided into three 3.2-ha paddocks, and cows were rotated each week from mid-April through mid-October. The Coastal Plain soils in each pasture received a total of 190 kg of nitrogen (N) per ha per year in five split applications of 38 kg N per ha on 21-d intervals. Cows were wintered on the same pastures with a bermudagrass hay-soybean meal and milo diet. Interactions of year by forage, year by breed, and year by breed by forage were nonsignificant for weaning rate (P>.05). Weaning rate was not affected by the interaction of forage by breed (P .05). These data suggest that the HBR cow was more productive than the BG cow on both T44HB and CBD pastures under intensive grazing management.

Relationships of Hoof Characteristics and Selected Hoof Minerals of Bulls in a 112-Day Postweaning Feedlot Performance Test1

Observations on hoof growth of Angus (n = 20), Brangus (n = 19), Hereford (n = 31), and Simmental (n = 53) during a 112-d postweaning feedlot performance test were used to study hoof characteristics relative to hoof mineral composition. Hoof measurements, scores, and .5-g hoof samples were obtained from the right front foot of all bulls on d 1 and 112 of four tests conducted in three locations in Arkansas. Data were analyzed using least squares analysis of variance. The model used included terms for an overall mean, test, breed, farm of origin within breed, initial age, and initial weight within breed and residual error. Means were separated using repeated t-test. Residual correlation coefficients were obtained from the residual sum of squares. Test and breed were significant for hoof angle but not for hoof growth, hoof score, and hoof pigment. Farm of origin within breed, initial age, and initial weight within breed were not significant for any hoof trait. The model explained .72, .39, .42, and .83 of the variation (R2) of the main effects of hoof angle, hoof growth, hoof score, and hoof pigment, respectively. Hoof angle for Angus and Brangus bulls was different (P<.05) than hoof angle of Hereford and Simmental bulls. Significant residual phenotypic correlations were found for hoof angle, hoof growth, and hoof score with some hoof minerals. These data indicate that there are breed effects on hoof angle and that a relationship exists among the mineral content of hooves and both hoof measurements and scores.