In December of 3 years, 87 beef cows with nursing calves (.594 ± 9.8 kg; calving season, September to November) at side were stratified by body condition score, body weight, cow age, and calf gender and divided...In December of 3 years, 87 beef cows with nursing calves (.594 ± 9.8 kg; calving season, September to November) at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures (0.45 ha/cow) that had been interseeded into a dormant common bermudagrass (Cynodon dactylon [L.] Pers.)/bahiagrass (Paspalum notatum Flugge) sod. Pastures contained 1 of the following 3 seeding mixtures (2 pastures/mixture): 1) wheat (Triticum aestivurn L.) and ryegrass (Lofium multiflorum Lain., WRG), 2) wheat and ryegrass plus red clover (Trifolium pretense L, WRR), or 3) wheat and ryegrass plus white (Trifofium repens L.) and crimson clovers (Trifolium incarnatum L., WRW). All groups had ad libitum access to grass hay (12% crude protein; 58% total digestible nutrients). The second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ (P ≥ 0.27) among cows between February and June. Calf birth weights or average daily gain did not differ (P≥ 0.17) among treatments; however, calves grazing pastures with clovers did tend (P= 0.06) to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater (P= 0.02) for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.展开更多
对白三叶RAPD反应体系中的模板DNA用量、随机引物浓度、dNTP浓度、TaqDNA聚合酶浓度、M g2+浓度分别进行了梯度试验。结果表明,在总体积25μL体系中,模板DNA 20 ng、引物9.9 ng、dNTP浓度0.4 mm o l/L、T aqDNA聚合酶3 U、M g2+浓度1 mm...对白三叶RAPD反应体系中的模板DNA用量、随机引物浓度、dNTP浓度、TaqDNA聚合酶浓度、M g2+浓度分别进行了梯度试验。结果表明,在总体积25μL体系中,模板DNA 20 ng、引物9.9 ng、dNTP浓度0.4 mm o l/L、T aqDNA聚合酶3 U、M g2+浓度1 mm o l/L的反应体系可得到稳定清晰的RAPD扩增图谱,该体系可用于白三叶遗传多样性分析。展开更多
文摘In December of 3 years, 87 beef cows with nursing calves (.594 ± 9.8 kg; calving season, September to November) at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures (0.45 ha/cow) that had been interseeded into a dormant common bermudagrass (Cynodon dactylon [L.] Pers.)/bahiagrass (Paspalum notatum Flugge) sod. Pastures contained 1 of the following 3 seeding mixtures (2 pastures/mixture): 1) wheat (Triticum aestivurn L.) and ryegrass (Lofium multiflorum Lain., WRG), 2) wheat and ryegrass plus red clover (Trifolium pretense L, WRR), or 3) wheat and ryegrass plus white (Trifofium repens L.) and crimson clovers (Trifolium incarnatum L., WRW). All groups had ad libitum access to grass hay (12% crude protein; 58% total digestible nutrients). The second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ (P ≥ 0.27) among cows between February and June. Calf birth weights or average daily gain did not differ (P≥ 0.17) among treatments; however, calves grazing pastures with clovers did tend (P= 0.06) to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater (P= 0.02) for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.
文摘对白三叶RAPD反应体系中的模板DNA用量、随机引物浓度、dNTP浓度、TaqDNA聚合酶浓度、M g2+浓度分别进行了梯度试验。结果表明,在总体积25μL体系中,模板DNA 20 ng、引物9.9 ng、dNTP浓度0.4 mm o l/L、T aqDNA聚合酶3 U、M g2+浓度1 mm o l/L的反应体系可得到稳定清晰的RAPD扩增图谱,该体系可用于白三叶遗传多样性分析。