牦牛鞭中几种微量元素含量的测定

牦牛鞭是高原动物牦牛的干燥的阴茎和睾丸 ,在民间常食用 ,据说能“温肾壮阳 ,益精补髓”,具有与鹿鞭相类似的功效。鹿鞭、牛鞭的微量元素含量已有文献记载 〔1,2〕,但对牦牛鞭的微量元素含量尚未见报道 ,因此我们开展了此次实验 ,测定了带睾丸的牦牛鞭、不带睾丸的牦牛鞭、新鲜不带睾丸的牦牛鞭中几种微量元素含量 ,现报道如下。1　材料与方法1.1　仪器国产 36 1MC型原子吸收分光光度计、72 1分光光度计、组织捣碎机、马弗炉等。1.2　试剂硝酸、磷酸、盐酸、硫酸、高氯酸、硫氰酸钾、过硫酸钾 ,均为 A· R级 ,重蒸馏水。1.3　测定样品牦…     

天峻地区牦牛乳中微生物含量的测定

随着西部开发的进一步加快和人民生活水平的不断提高,广大消费者对牛乳的需求量愈来愈大,尤其是地处青海高原、以畜牧业生产为主的天峻县,人们对牦牛乳的饮用量逐年上升.     

麦洼牦牛初乳和常乳中超氧化物歧化酶活力的研究

研究了麦洼牦牛脱脂乳中超氧化物歧化酶 (SOD)的活力。结果显示 :牦牛初乳 (泌乳第 1～ 7天 )中SOD活力(Nu/mL)分别为 31 4 6 3± 39 5 1、35 5 73± 39 1、36 4 4 9±2 2 1 7、32 4 73± 30 6、31 3 96± 1 8 0 0、31 6 6 5± 1 9 5 1、31 7 5 2± 1 0 6 8,常乳中的活力为 2 92 4 9± 6 96Nu/mL。与常乳相比 ,泌乳第 3天的初乳中SOD活力显著高于常乳 ,其余各天差异不显著。半奶牦牛和犏牛乳中SOD活力分别为 1 89 75± 1 1 71和 1 2 5 6 5± 2 2 9,均极显著低于常乳     

麦洼牦牛干乳期乳的生化性质

分析了１９头麦洼牦牛干乳期乳中γ－谷胺酰转肽酶，淀粉酶，碱性磷酸酶，乳过氧化物酶的活力，乳蛋白，乳糖，乳脂的含量及乳蛋白的组成，并测定了Ｋ，Ｎａ，Ｃａ，Ｍｇ，Ｐ的含量。结果显示：同常乳期相比，干乳期乳中γ－ＧＴ，ＡＫＰ的活力及乳蛋白，乳脂的含量显著提高，而乳糖含量下降。     

牦牛干酪中矿物质和蛋白质含量分析

用原子吸收法测定了牦牛干酪中几种矿物质元素的含量。结果表明，干酪中含有丰富的Ca、P、Fe、Zn等元素。另外，测得干酪中粗蛋白含量约为740g／kg，在PAGE上主要显示αs1-酪蛋白和β-酪蛋白区带。     

藏山羊及其杂交后代乳中矿物质含量的分析

测定了藏山羊及其同安哥拉山羊杂交一代乳中Ｋ、Ｎａ、Ｃａ、Ｐ、Ｍｇ的含量。结果显示：藏山羊及其杂交后代乳中的Ｃａ含量显著高于牛乳，其它元素的含量接近牛乳。同藏山羊相比，杂交一代乳中Ｃａ含量高，Ｐ含量罗低。还发现，藏山羊初乳中Ｎａ、Ｍｇ的含一显著高于常乳，而Ｋ的含鞭工于常乳，反映了乳腺在初期期矿物质的分泌特点，该结果为山羊乳的研究利用及羔羊的饲养提供了一定依据。     

人乳与牛奶中宏量与微量元素含量研究综述

本文综述了近年来国内外对人乳与牛奶中宏量与微量元素含量进行的研究，包括：1．牛奶中宏量与微量元素含量，2．人乳中宏量与微量元素含量，3．人乳与牛奶中微量元素含量差异原因分析，4．讨论     

藏药牦牛骨主要矿物质元素的主因子分析

用因子分析法对藏药牦牛骨4个部位的12种微量元素测定数据进行了多因素分析.结果表明:2个主因子能合理解释这些微量元素之间的相关关系,从而达到压缩原变量的目的.     

Nucleotides in sow colostrum and milk at different stages of lactation

An experiment was conducted with the objective of measuring the concentrations of total milk solids (TMS), CP, and 5'monophosphate nucleotides in sow colostrum and milk. Twelve multiparous sows (Landrace x Yorkshire x Duroc) were used. Litter size was standardized at 11 piglets for all sows at farrowing. Sows were fed an 18.45% CP corn-soybean meal-based diet throughout lactation. The experimental period was the initial 28 d of lactation, with colostrum collected within 12 h of farrowing and milk collected on d 3, 7, 14, 21, and 28. Colostrum and milk samples were analyzed for TMS, CP, adenosine 5'monophosphate (5'AMP), cytidine 5'monophosphate (5'CMP), guanosine 5'monophosphate (5'GMP), inosine 5'monophosphate (5'IMP), and uridine 5'monophosphate (5'UMP). Total milk solids decreased (P < 0.05) from 26.7% on d 0 to 23.1% on d 3. The TMS further decreased (P < 0.05) to 19.3% on d 7, but remained relatively constant thereafter at 18.2, 18.8, and 19.2% on d 14, 21, and 28, respectively. The concentration of CP decreased from 16.6% in colostrum to 7.7, 6.2, 5.5, 5.7, and 6.3% in milk collected on d 3, 7, 14, 21, and 28, respectively (linear and quadratic effect; P < 0.05). Concentrations of 5'AMP, 5'CMP, 5'GMP, and 5'IMP increased from d 0 to d 3 and d 7, and then decreased during the remaining lactation period (quadratic effect; P < 0.05). The concentration of 5'UMP decreased from d 0 to 28 of lactation (linear and quadratic effects; P < 0.05). In colostrum, 5'UMP represented 98% of all 5'monophosphate nucleotides, and in milk, 5'UMP accounted for 86 to 90% of all nucleotides, regardless of day of lactation. The results of this experiment suggest that the concentrations of TMS and CP in sow mammary secretions changed during the first week of lactation, but were constant thereafter. Likewise, the concentrations of 5'monophosphate nucleotides changed during the initial week postpartum, but during the last 2 wk of a 4-wk lactation period, the concentrations were constant.     

Longitudinal analysis of clinical mastitis at different stages of lactation in Norwegian Cattle

Genetic variation and covariation of liability to clinical mastitis in the course of first lactation in Norwegian Cattle (NRF) were investigated. The data consisted of 36,178 first-lactation cows with 354,506 clinical mastitis (absence=0 vs. presence=1) monthly records. A longitudinal binary data analysis was carried out using Bayesian threshold models and Markov chain Monte Carlo (MCMC) procedures. Liability was related to stage of lactation using random regression functions: the Ali–Schaeffer function (AS), the Wilmink function (W) and Legendre Polynomials of order 2, 3 or 4 (L2, L3, L4). Models were compared using a pseudo Bayes factor and an analysis of residuals. The MCMC scheme for the AS function did not converge after 20,000 iterations, and was therefore excluded from further analysis. The pseudo Bayes factor strongly favored the L4 model. Most posterior means of the residuals fell in the range from −0.2 to 0 when cows were healthy (a residual is negative when mastitis is absent and positive otherwise). The L4 model tended to have smaller residuals than the other three models when cows had mastitis. The posterior means of the herd variance and of the cow-specific variance were 0.0645 and 0.1084, respectively, for the fourth order Legendre polynomial. Heritability of liability to clinical mastitis was from 7% to 13% before calving, and ranged between 3% and 11% from calving to 260 days after calving. Most genetic correlations of liability to clinical mastitis between different days of first-lactation ranged from 0.4 to 0.7.     

不同泌乳阶段奶牛血清矿物元素含量的变化

试验旨在探讨不同泌乳阶段和产奶量对奶牛血清矿物元素含量的影响。试验采用2×5(产奶量:高产≥35 kg/d和低产<35 kg/d;泌乳阶段:围产前期、围产后期、泌乳前期、泌乳中期和泌乳后期)二因素完全随机试验设计,选择40头荷斯坦奶牛,分析产奶量与泌乳阶段对血清常量元素(钙、磷、钾、镁)与微量元素(镉、钴、铬、钼、铅、铜、锰、硒、铁、锌)含量的影响。结果表明产奶量对血清矿物元素含量无显著影响(P>0.05),泌乳阶段对血清矿物元素含量影响显著(P<0.05)。除泌乳后期外,其它阶段血清铜含量均较低,接近阈值;泌乳前期和围产后期血清硒及围产后期钴含量较低,且低于正常范围;各阶段血清铁含量均较低;泌乳后期铅含量高于正常范围;其它各阶段其余元素含量均在正常范围内。因此,生产中应针对不同生理阶段注意元素铁、硒、铜、钴的及时供给,并预防泌乳后期铅中毒。     

Thiobarbituric acid reactive substances and plasma antioxidative capacity in dairy cows at different lactation stages

The aim of the present experiment was to investigate the level of the lipid peroxidation and plasma antioxidative capacity in plasma of dairy cows at different lactation stages. Twenty six healthy dairy cows were used in our experiment. The groups: I - dry cows (n = 7), II - dairy cows < 1 month after calving (n = 9), III - dairy cows 4 - 5 months after calving (n = 10). The highest level of lipid peroxidation (TBARS) was recognized in dairy cows in early lactation (II - 0.58+/-0.42 micromol/l) with significant differences between the groups (p < 0.05). In contrast, there was a tendency (p > 0.05) to the lowest plasma antioxidative activity in cows in the same group (158 +/- 44 micromol/l). The strongest trend to metabolic imbalance was found in the dairy cows in early lactation (group II). In conclusion, the metabolic stress of dairy cows associated with early lactation resulted in an increased level of plasma lipid peroxidation.     

Proteomic analysis of Tianzhu White Yak (Bos grunniens) testis at different sexual developmental stages

To explore the protein expression profiles of white yak (Bos grunniens) testis at different sexual developmental stages. The protein profiles of yak testis were determined using two‐dimensional electrophoresis and the expression levels of 298 protein spots were analyzed. Mass spectrometry was performed to identify those significantly differential expressed proteins; Western blotting was used to confirm the results. During the developmental stages, 29 protein spots showed more than twofold differences (p < 0.05) at ≥1 time point and were successfully identified. Two proteins were upregulated with age (category 1), five proteins (17.2%) were downregulated with age (category 2), four proteins were upregulated before 4 years of age and downregulated thereafter (category 3), fifteen proteins were upregulated before 2 years of age and downregulated thereafter (category 4), and three proteins fluctuated with age (category 5). The expression patterns of regucalcin and heat shock 60 kDa protein in category 2 were confirmed. The 29 differentially expressed proteins from yak testes (some had more than one function) were categorized into binding (n = 15), catalytic activity (n = 13), molecular function regulator (n = 4), antioxidant (n = 4), molecular transducer (n = 2), transporter (n = 1), and structural molecule (n = 1). The identification and analysis of these testis proteins may assist in understanding the developmental biology of reproduction system in male yak.     

Improvement of lactation milk and persistency using the eigenvectors of the genetic covariance matrix between lactation stages

First lactation milk production of Japanese Holstein cows was partitioned into ten stages. A quartic Legendre polynomial (k = 5) under an animal model was used to estimate the additive genetic covariance matrix between these ten stages. Various selection indexes with or without restrictions were constructed using the eigenvectors of the genetic covariance matrix. These eigen indexes were designed to improve lactation milk and persistency defined as difference in milk between DIM 280 and DIM 55. Two sets of economic weights between lactation milk and persistency and three levels of restriction on the intended gains in persistency were applied. The unrestricted index based on the first three eigenvectors achieved more than 99.9% of the net merit of the unrestricted index based on the first five eigenvectors. The advantage of unrestricted index over conventional selection based on lactation EBV increases with increasing economic weight assigned to persistency. The construction of the restricted eigen index does not require economic values between lactation milk and persistency and thus is more practical than the unrestricted eigen index which requires information on the economic values of both. The index coefficients of the eigen indexes reveal the relative selection emphasis among various stages of the lactation. When the degree of restriction or economic value for persistency increases, a greater selection emphasis was placed on the later part of the lactation than on the early part in order to realize the desired persistency. The developed eigen indexes provide useful information and easy understanding of the selection practice. A numerical example was given to illustrate the construction of the restricted eigen index.     

Immunocyte populations in the mammary gland of the rat at different stages of pregnancy and lactation.

Immunocyte populations of apparently normal rat mammary glands were examined at different stages of lactation using immunofluorescence techniques. IgA-and IgG-containing cells were present before parturition; IgA-containing cells were numerous than IgG- or IgM-containing cells during the entire period from pregnancy through parturition and lactation to involution.     

Relationship between the lactation curve and udder disease incidence in different lactation stages in first‐lactation Holstein cows

We examined the relationships between the shape of the first parity lactation curve and udder disease incidence at different stages of lactation in 538 Holstein cows. Data used were first‐parity daily milk yields and treatment records. Each cow was classified according to whether or not it had had udder disease at least once over the whole lactation period or in one of three stages within the lactation period. We then examined the differences in the shapes of the lactation curves between the disease incidence and non‐incidence group in each stage. Cows that had high rates of increase in milk yield and high milk yields in early lactation were predisposed to udder disease afterwards. Cows with high milk production over a long period but with low lactation persistency were predisposed to udder disease after the peak of lactation. There was no difference in total milk yield between incidence and non‐incidence groups in all stages, suggesting that, for a comparable level of lactation, cows without udder diseases have flatter lactation curves.     

甘油代替大麦对泌乳中后期奶牛采食量、产奶量和乳质量的影响

文章旨在确定在不影响牛奶产量、牛奶成分、乳脂肪酸组成和牛奶感官质量的情况下,用不同水平甘油代替大麦对泌乳中后期奶牛的影响。试验选择了40头荷斯坦奶牛,采用4×4拉丁方试验设计。在部分混合日粮中,粗甘油替代大麦的含量分别为日粮干物质的0、6%、12%和18%。每天记录个体产奶量、采食量和挤奶频率,每周分析牛奶成分。对新鲜牛奶和贮藏7 d的牛奶样品进行感官分析。部分混合日粮的摄入量随甘油添加水平由0升高至12%,增加近1 kg,甘油由12%升高至18%,减少约1 kg。甘油水平由0升高至6%时,精料摄入量下降0.5 kg。随着日粮中甘油比例的增加,牛奶产量呈线性下降(P<0.05),而牛奶中的脂肪和蛋白质含量呈上升趋势(P=0.08),导致能量校正乳水平随甘油水平的升高表现为二次曲线效应,其中6%甘油组产量最高,18%甘油组产量最低。蛋白质和乳糖产量随日粮中甘油比例的增加线性下降(P<0.05)。随着日粮甘油比例的增加,牛奶中棕榈酸、油酸、亚油酸、亚麻酸和共轭亚油酸的比例线性下降(P<0.05),而短链和中链脂肪酸的比例大部分呈上升趋势。综上所述,甘油作为一种能量饲料可以在不影响牛奶品质的前提下,在泌乳中后期奶牛日粮中替代大麦的水平高达18%。但日粮甘油水平超过12%时可能会降低能量校正乳的产量。