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141.
142.
河西走廊酿酒葡萄热量条件鉴定 总被引:1,自引:0,他引:1
运用相关分析和Log istic生长曲线方法,对河西走廊酿酒葡萄田间试验观测资料进行了分析,确定了酿酒葡萄的关键生育期以及全生育期各生育阶段温度指标和低温冻害指标,为河西酿酒葡萄区域化生产提供了可供参考的气候资料。 相似文献
143.
奶牛发情周期中毛 唾液和乳汁孕酮水平的变化 总被引:1,自引:0,他引:1
本实验采用放射免疫分析法(RIA)测定了11头奶牛一个发情周期里毛、唾液、乳汁中孕酮(P_4)含量。经产牛(n=8)的毛和唾液中P_4水平变化与乳汁中P_4水平变化一致。青年牛(n=3)的毛和睡液中的P_4水平变化一致,并分别与经产牛毛和唾液中P_4水平变化一致。7头配种后的经产牛和5头配种后的青年牛分别取20和23天的样品进行妊娠诊断,与配种后60天的直检结果相对照,依据经产牛毛、乳P_4水平进行妊娠诊断的阳性准确率分别是85.7%(6/7)和100%(7/7),依据青年牛毛P_4水平进行妊娠诊断的阳性准确率为100%(5/5)。 相似文献
144.
145.
近红外反射光谱(NIRS)技术分析奶粉品质的研究 总被引:6,自引:0,他引:6
奶粉中蛋白质和脂肪是影响奶粉营养品质的主要因素,利用近红外反射光谱分析技术对来自国内不同地区的奶粉共900份样品进行蛋白质和脂肪成分测定分析。研究了不同的样品数日、光谱预处理和散射校正技术对发展奶粉近红外测定定标模型的影响。结果表明.在样品数目为200—400范围内建立的定标分析模型较理想;数学预处理中以一阶导数较好,且以“1,4,4,1”的处理组合最为理想;光谱散射校正中采用“标准正态变量转换(SNV) 趋势变换法(De—trending)”的组合建立回归方程效果较好。利用改进最小二乘法回归技术(Modified PLS)建立多种定标模型,并进行交叉验证(cross—Validation)来分析各种因素对定标模型的影响。同时筛选出较理想的蛋白质和脂肪定标分析回归方程,其中蛋白质和脂肪含量的相关系数高速0.973和0.850。探讨了NIRS技术在建模应用中的一些影响因素,以及由NIRS技术建立奶粉分析模型用于快速分析和在线检测的可行性。 相似文献
146.
Comparison of milk production of dairy cows kept in cold and warm loose-housing systems 总被引:2,自引:0,他引:2
A retrospective cohort study was conducted to test whether the lactation curves of cows kept in cold loose-housing systems (CLHs) were the same as for cows in warm loose-housing systems (WLHs) in the Nordic countries. Approximately 40 000 test-day records from 5366 Ayrshire or Black and White cows kept on 38 CLHs and 166 WLHs in Finland during 1996 and 1997 were used. Analysis used a random-coefficient model (correcting for parity, breed and calving-year-season and the correlation-structure between test-days of the same cow and cows of the same herd). Cows in a CLH produced up to 1 l less milk per test-day, but this difference was not statistically significant. Surprisingly, the difference in milk yield was not affected by calving-year-season, parity or breed. 相似文献
147.
A grazing experiment, conducted for 90 days compared the effect of polyethylene glycol (PEG) supplementation on postpartum reproductive traits and productivity of suckling goats grazing Acacia cyanophylla Lindl. A total of 54 native adult goats (34.4 ± 5.49 kg) were randomly allocated, 24 h after kidding, to 2 treatment groups balanced for age and the number of reared kids. Goats in both treatment groups designed C and PEG grazed in acacia for approximately 5 h every day and received each on daily basis 0.3 and 0.4 kg of hay and concentrate respectively. In addition, goats in treatment PEG were initially supplemented with 10 g/day of PEG and this supplement was then increased to 20 g /goat/day over the last 60 days of the trial. Goats receiving PEG tended (P > 0.05) to spend more time browsing acacia than those in treatment C. There were no treatment effects on live weight change of the goats, growth of their kids until 90 days of age or composition of their milk in terms of fat, protein and urea contents. Similar proportions of 74.1 and 77.8% of goats resumed postpartum ovulation with a mean ovulation rate of 1.50 ± 0.61 and 1.67 ± 0.47 (P > 0.05) in respectively the PEG and C treatments. PEG supplementation was associated with an increase (P < 0.05) in ovulation rate at the second postpartum ovulation occurring approximately 27 days after the application of the nutritional treatments (1.76 ± 0.60 versus 1.25 ± 0.45); 9 of the 13 goats ovulating in the PEG treatment were bearing more than one corpus lutuem in comparison to only 3 out of 12 females in the C group (P < 0.05). The likely increased availability of proteins in the PEG receiving goats could explain their higher ovulation rate. 相似文献
148.
149.
The objective of this study was to examine the effect of long day photoperiod (LDPP) on milk production and reproduction in milk goats. A total of 79 goats were randomly assigned to three treatment groups blocked by day of kidding. Group 1 (Gr1, n = 26) was subjected to natural photoperiod from January 6 to December 5. Group 2 (Gr2, n = 24) was subjected to LDPP (20 h light, 4 h dark) from June 22 to December 5. Group 3 (Gr3, n = 29) was subjected to LDPP from January 6 to December 6. Weekly milk weights and samples were collected for fat, protein and somatic cell count (SCC) determinations. Blood serum was harvested for progesterone (P4) determination. Results indicated a significant effect (p < 0.001) between treatments for body weight changes, feed intake and milk yield. Both light treated groups had a significantly higher (p < 0.001) average daily milk output for the entire lactation period than the control group (G1, 2.193 kg/day; G2, 2.517 kg/day; G3, 2.305 kg/day). Milk fat for the overall lactation was significantly higher in Gr3 (+ 0.19 g/100 ml) than for Gr2 (+ 0.06 g/100 ml) when compared to the control group (x g/100 ml) under natural photoperiod. Somatic cell counts throughout lactation were significantly (p < 0.001) lower for Gr2 (1.70 million/ml) and higher for Gr3 (2.03 million/ml), with the control group (Gr1) having an intermediate level (1.96 million/ml). Progesterone levels between June 9 and August 30 indicated that 27%, 48% and 63% of the animals had P4 levels in excess of 1.0 ng/ml serum for Gr1, Gr2 and Gr3, respectively. Pregnancy diagnosis by ultrasound in December revealed that a high number of does in the light treated groups (10 of 37) were pseudo-pregnant when compared with the control group (1 of 21). Although light appeared to be effective in increasing milk production, further investigations are needed to evaluate the effect of LDPP on pseudo-pregnancy in dairy goats. 相似文献
150.