Data were collected on 476 spring-calving, primiparous cows at six locations in Louisiana over a 2-yr period. Objectives of the study were to evaluate changes in prepartum body condition score (BCS) and BW of heifers when fed varying energy levels and to determine the influences of prepartum BCS and BW changes and BCS at calving on postpartum traits. Heifers were allocated to one of three energy levels from approximately 90 d prepartum to parturition. The diets were formulated to provide low, recommended, and high energy levels based on TDN requirements. After calving, cows were placed on annual ryegrass pasture and managed similarly at each location. Weight and BCS at calving were greater (P < .05) for females with higher BCS at 90 d prepartum (IBCS) and for those assigned to higher energy levels. Calving and calf growth traits were not affected (P > .05) by IBCS, energy level, prepartum changes in BCS and BW, or BCS at calving. Prepartum changes in BCS and BW regulated by varying energy levels had no effect (P > .05) on postpartum reproduction; however, BCS at calving influenced (P < .03) pregnancy rate and days to pregnancy. Cows with BCS 6 and 7 at calving had higher (P < .05) pregnancy rates (87.0 and 90.7%) than those with BCS 4 and 5 (64.9 and 71.4%). Interval to pregnancy for cows with BCS 4 at calving was 10 to 18 d longer (P < .05) than for those with BCS > or = 5.(ABSTRACT TRUNCATED AT 250 WORDS)

The antimicrobial susceptibility to 11 antibiotics was determined of 358 streptococcal isolates representing six species was determined. All isolates were from milk samples obtained from clinical or subclinical cases of bovine mastitis. Agar disk diffusion zone diameters and minimum inhibitory concentrations were obtained for all isolates. Of the antibiotics tested that are available for mastitis therapy, cephalothin, penicillin, ampicillin, novobiocin, and erythromycin demonstrated acceptable activity against nonenterococcal streptococci, but only penicillin and ampicillin demonstrated moderate activity against Enterococcus faecalis. Enterococcus faecalis demonstrated substantial resistance to cephalothin, erythromycin, gentamicin, streptomycin, and tetracycline, while the nonenterococcal streptococci demonstrated substantial resistance to gentamicin, streptomycin, and tetracycline. Streptococcus uberis demonstrated greater antibiotic resistance than did Streptococcus dysgalactiae, while Aerococcus viridans demonstrated the greatest overall resistance of the nonenterococcal species.

‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] provides the opportunity to produce large quantities of forage for grazing stocker cattle (Bos taurus, Bos indicus). Other hybrids have been developed that may increase stocker gains through good forage yield and better quality than is provided by Coastal. A 4‐yr study compared overall and seasonal performance of stocker steers grazed on ‘Brazos’, ‘Grazer’, Coastal, and ‘Tifton‐44’ bermudagrass cultivars. Established paddocks were grazed continuously for an average of 154 d (24 April‐25 September) each year (1982‐1985). Annual fertilization rates were 306‐26‐174 lb/acre of N‐P‐K. Average stocking rate was 4.4 steers/acre. Grazer produced the greatest weight gains (1183 lb/acre; P < 0.05), while gains produced by other cultivars averaged 1003 lb/acre and were not different (P > 0.05). Steer weight increased rapidly in May, slowed during June, July, and August, and increased again during September. Grazer showed an advantage in rate of gain over other cultivars during the summer months.

Production of hybrid bermudagrass [Cynodon dactylon (L.) Pers.] requires stand establishment by vegetative means. Sprigs (rhizomes and rooted stolons) are the method of choice, but vegetative culms (cuttings) are often used because of lower planting material costs. Two studies, one in raised beds in a greenhouse (1987 and 1989) and one under field conditions (1989), were conducted during the summers of those years to investigate differences in survival of cuttings from four hybrid bermudagrass cultivars at 2, 4, 6, 8, and 10 wk of age. In raised beds, percent survival of Coastal (49%) was higher than Grazer (31%) and Tifton‐44 (24%); Brazos (41%) was higher than Tifton‐44. Cutting length and number of nodes were related to survival and reduced the proportion of variation in percent survival attributable to cutting age when included in analysis of variance models as covariates. Grazer and Brazos had higher survival than Coastal and Tifton‐44 after adjusting data for cutting length. A cultivar‐×‐age interaction affected survival in the field study. All the above results were significant at P < 0.05. Analysis of data by cultivar resulted in significant effects of age on survival of Brazos clippings, and no effect (P > 0.05) of age on survival of other cultivars.

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