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)
Steers were generated from Angus (A), Beefmaster (BM), Brangus (BA), Gelbray (GB), and Simbrah (SB) sires mated to cows of their breed and to Brahman x Hereford F1 cows (except A) to characterize their carcass traits, composition, and palatability. The 290 steers (48 A, 48 BM, 36 BA, 31 GB, and 46 SB) were slaughtered at an equal fatness end point as determined by real-time ultrasound and visual evaluation. Angus steers had lighter (P < 0.01), more youthful (P < 0.01) carcasses with a higher (P < 0.05) quality grade, more (P < 0.01) fat thickness, and a larger (P < 0.01) longissimus area/100 kg than BM-, BA-, GB-, and SB-sired steers. Angus steers also had a lower (P < 0.01) specific gravity, a higher (P < 0.01) percentage fat and less (P < 0.05) lean in the 9th to 11th rib, and steaks aged for 10 d were more tender (P < 0.01) than steaks from Brahman-derivative sired steers. The BM- and BA-sired steers had lighter (P < 0.01), more youthful (P < 0.05) carcasses, and smaller (P < 0.01) longissimus area than GB- and SB-sired steers. The 9th to 11th rib section from the BM- and BA-sired steers had less lean and more bone (P < 0.01) than GB- and SB-sired steers. The BA-sired steers had more (P < 0.01) marbling and a higher (P < 0.05) quality grade than BM-sired steers. The SB-sired steers had heavier (P < 0.01) carcasses than the GB-sired steers. There were no differences in shear force for steaks aged for 3 d for any of the breed types, but with 10 d of aging, steaks from Angus steers were more tender, possibly indicating that steaks of Brahman-derivative breeds aged at a slower rate than those from Angus.
vives well under heavy grazing and has excellent forage nutritive value when properly managed (Holt, 1956). Common dallisgrass (Paspalum dilatatum Poir.) is an importantReported digestibility ranges from 570 to 630 g kg Ϫ1 forage grass in many subtropical regions including the southeastern USA. The term dallisgrass is synonymous with the common biotype. and crude protein (CP) can range from 44 to 232 g kg Ϫ1There are other biotypes of this species but little is known about their (Committee on Animal Nutrition and Feed Composiforage potential. This study was initiated to evaluate accessions of tion, 1971). five dallisgrass biotypes (common, prostrate, Torres, Uruguaiana, and Several factors limit forage production of dallisgrass. Uruguayan) and 'Pensacola' bahiagrass (P. notatum var. saurae Pa-Establishment can be difficult because of poor seed rodi) for forage yield, nutritive value, and persistence in southern quality and slow germination (Holt, 1956). Germination Louisiana and southeastern Texas, and to determine the response of commercially available seed is often less than 50%, and persistence of the superior biotypes under grazing. Three years and seed production is limited by low seed set and ergot of clipping data were collected at Baton Rouge, LA, and College (Claviceps paspali Stevens & Hall) infection. Ergot pro-Station, TX. Most of the Uruguayan accessions were equal or superior duces ergovaline, which causes serious animal health to common dallisgrass for yield and nutritive value and all had superior stand persistence. The Torres and Uruguaiana biotypes did not survive problems (Mayland and Cheeke, 1995). after the first harvest season. Forage production and persistence of Common dallisgrass is an obligate apomict with 50 prostrate dallisgrass and Pensacola bahiagrass were better than exchromosomes that associate as 20 bivalents and 10 unipected. Six superior accessions of the Uruguayan biotype and common valents during metaphase I of meiosis (Bashaw and dallisgrass were evaluated under grazing for 3 yr at Jeanerette, LA. , 1958; Bashaw and Holt, 1958). Attempts to im-After 2 yr of rotational stocking, an average of 90% of the Uruguayan prove the grass through breeding have not been successand only 53% of the common dallisgrass plants survived. This was ful because of apomixis and irregular meiosis, which followed by one season of continuous stocking and the average plant results in low quality pollen. survival decreased to 75% for the Uruguayan accessions and 33% for Besides common dallisgrass, there are four other dalcommon. Because the yield and persistence of the Uruguayan biotype lisgrass biotypes [prostrate (P. dilatatum var. pauciciliawas consistently superior to that of common, Uruguayan dallisgrass could provide livestock producers in the southeastern USA with a tum Parodi), Torres, Uruguaiana, and Uruguayan] that viable alternative to common dallisgrass. Forbes
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