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Stacey A Gunter Whitney A Whitworth T Gregory Montgomery Paul A Beck 《畜牧与生物技术杂志(英文版)》2012,3(4):221-226
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 aestivum L.) and ryegrass (Lolium multiflorum Lam., WRG), 2) wheat and ryegrass plus red clover (Trifolium pretense L., WRR), or 3) wheat and ryegrass plus white (Trifolium 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. 相似文献
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用微波炉加热法快速测定三叶草含水量。结果表明:微波炉法较烘箱法测定值精确度高、准确性好;在测定高水分(67%～80%)红三叶时,采用5min法好,而在测定低水分(44%～66%)红三叶时,采用4min法好;红三叶的取样大小分别为10g、15g、20g、25g,其间差异不显著;白三叶水分测定用微波炉4min法好,取样大小以15g、20g较好。 相似文献
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ABSTRACT: 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 aestivum L.) and ryegrass (Lolium multiflorum Lam., WRG), 2) wheat and ryegrass plus red clover (Trifolium pretense L., WRR), or 3) wheat and ryegrass plus white (Trifolium 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 [greater than or equal to] 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. 相似文献
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利用盆栽试验,对白三叶(Trifolium repens L.)2份耐盐品种1212和83-160以及2份敏盐品种83-159和81-1进行苗期耐盐性研究,通过对存活率、株高、电导率、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性等指标的测定与分析,探讨盐胁迫下白三叶生长情况及保护酶活性的响应。结果表明:随着盐浓度的升高,4个品种的存活率和相对株高均呈显著下降趋势,电导率呈上升趋势。耐盐品种1212和83-160的存活率和相对株高均显著高于敏盐品种81-1和83-159,电导率则显著低于敏盐品种,说明敏盐品种在盐胁迫下细胞受损更严重。随着胁迫时间的延长SOD,POD和CAT活性均表现为先急剧上升后下降之后再上升的趋势,耐盐品种和敏盐品种变化差异显著,在盐胁迫后5 d和10 d时,耐盐品种的3种酶活性低于敏盐品种,而盐胁迫后20 d时,耐盐品种酶活性和敏盐品种趋于一致,这可能是由于盐胁迫前期敏盐品种比耐盐品种中积累了更多的活性氧而使诱导酶活性提高。 相似文献
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