Transport of fatty acids within plasma lipoproteins in lactating and non‐lactating cows fed on fish oil and hydrogenated palm oil

The aim of this study was to elucidate the effect of dietary fish oil (FO) and a blend of FO and hydrogenated palm oil (FOPO) on transport of fatty acids (FA) within plasma lipoproteins in lactating and non‐lactating cows. Two trials were conducted (one with lactating and another with non‐lactating dairy cows) in two 3 × 3 Latin squares that included three periods of 21 days. Dietary treatments for lactating cows consisted of a basal diet (Control; no fat supplement), and fat‐supplemented diets containing FO (500 g/day/cow) and FOPO (250 FO + 250 g/day/cow hydrogenated palm oil). For non‐lactating cows, dietary treatments consisted of a basal diet (Control; no fat supplement), and fat‐supplemented diets containing FO (170 g/day/cow) and FOPO (85 FO + 85 hydrogenated palm oil g/day/cow). In lactating cows, compared with control and FOPO, FO increased C16:0, C18:3 cis‐9, 12, 15, C18:2 cis‐9, trans‐11 and total saturated and polyunsaturated FA in plasma and increased C16:0, C18:2 cis‐9, trans‐11, total polyunsaturated and total polyunsaturated n‐6 in high‐density lipoprotein (HDL), whereas in non‐lactating cows, compared with control and FOPO, FO increased C16:0, C18:1 trans‐11, C18:2 trans‐9, 12, C18:2 cis‐9, trans‐11, C20:5 n‐3 and total saturated and polyunsaturated FA in plasma; C16:0, C18:1 trans‐11, C18:1 cis‐9, C18:2 trans‐9, 12, C20:5 n‐3 and total monounsaturated FA in HDL; and C18:1 trans‐6‐8, C18:1 trans‐9, C18:1 trans‐10, C18:1 trans‐11, C18:3 cis‐9, 12, 15 and C20:5 n‐3 in low‐density lipoprotein (LDL). FO increased C20:5 n‐3 in plasma and lipoproteins in non‐lactating cows and increased C18:3 cis‐9, 12, 15 in plasma (in lactating cows) and LDL (in non‐lactating cows). We concluded from results of this study that in bovine plasma, the LDL fraction appears to be the main lipoprotein transporting C18:1 trans isomers and is more responsive than other lipoprotein fractions to variation in supply of dietary lipids.     

前茬小麦免耕和耕作对夏大豆田土壤含水量和产量的影响

研究了前茬小麦免耕和耕作2种方式对夏大豆田土壤含水量变化、夏大豆农艺性状及产量的影响.结果表明:前茬小麦免耕的全生育期0～20 cm的土壤平均含水量比耕作低1.06%,差异不显著;而前茬小麦免耕的20～40 cm、40～60 cm和60～80 cm土壤平均含水量比耕作的分别高0.36%、0.96%、0.97%,差异均不显著.前茬小麦免耕的和耕作的夏大豆平均产量分别为4253.6和4313.2 kg·hm-2,前茬小麦免耕比耕作的减产59.6 kg·hm-2,但差异不显著;前茬小麦免耕的和耕作对夏大豆生育期、百粒重等农艺性状均无显著影响.因此,夏大豆前茬小麦免耕不但取得与前茬小麦耕作同样的产量效果,而且还能节省劳动量,防止水土流失,保护土壤结构,消除犁地层对作物根系生长与吸收的影响,是值得推广的耕作模式.     

Free-range system and supplementation of 25-hydroxicholecalciferol increases the performance and serum vitamin levels in mixed-parity sows

Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg⁻¹. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL⁻¹; P = 0.035) and lactation (120.29 vs. 88.93 ng mL⁻¹; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.     

影响内蒙古三河牛泌乳曲线参数的非遗传因素

为了解三河牛泌乳曲线形状及其影响因素,试验对三河牛的486个泌乳期记录,应用Wood模型进行泌乳曲线拟合,结果显示,Wood模型能够较好拟合三河牛泌乳曲线,平均拟合优度R2为0.93±0.004。应用方差分析进一步研究场效应、产犊年度、产犊季节及胎次对Wood模型各参数的影响情况,结果表明,场效应对参数c、tmax、per、Y305影响差异极显著;不同产犊年度间,参数b表现为差异显著(P0.05),参数c、ymax、Y305表现为差异极显著(P0.01);各产犊季节间,参数a、b、c、Y305均表现为差异极显著(P0.01),参数per表现为差异显著(P0.05);胎次对参数a、ymax、Y305影响差异极显著(P0.01);其它参数与效应间均表现为差异不显著(P0.05)。     

Colostrogenesis during an induced lactation in dairy cattle

Colostrum immunoglobulin G (IgG) is of major importance for the newborn calf because epitheliochorial placentae do not provide transport in utero. The formation of colostrum occurs in the later stages of pregnancy. Our objectives were to induce lactation in non‐pregnant dairy cows and (i) to determine the changes of IgG in serum and mammary secretions during the induction process and (ii) to establish α‐lactalbumin (αLA) and prolactin (Prl) alterations to monitor the changing mammary epithelial tight junction status and development pattern. Estradiol‐17β (E2) and progesterone (P4) injections in a 1–7 days series were combined with a 3‐day injection series (day 21–23) of dexamethasone (DEX). Blood and both front quarter secretion samples were collected daily. Milking started 24 days after the start of the experiment. Results show that the mammary secretory IgG1 was increased at >7 days after the start of steroid injections and depicted a bimodal pattern reaching a high of 16 mg/ml at 21 day compared with 3.2 mg/ml in the serum. There was a small increase in secretory IgG2 that did not correlate with tight junction status, but never reached the serum concentration. The injections of DEX resulted in constriction of tight junctions. Secretory αLA was immediately increased with steroid injections, dropped precipitously after 7 days and then began a steady increase until the start of milking. Changes in serum αLA are related to mammary tight junctions while serum Prl gradually increased from 30 to >60 ng/ml after the steroid injections stopped. These results provide insights into the mechanisms and timing of colostrogenesis during an induced lactation protocol.     

The pharmacokinetics of thiamphenicol in lactating cows

The pharmacokinetics of thiamphenicol were studied after intravenous and intramuscular administration of 25 mg/kg body weight in lactating cows. Distribution (t _1/2) and elimination (t _1/2) half-lives of 6.10±1.39 min and 1.60±0.30 h, respectively, were obtained after intravenous administration. The body clearance was 3.9±0.077 ml/kg per min and the apparent volume of distribution was 1220.79±256.67 ml/kg. The rate at which thiamphenicol appeared in the milk, as indicated by the penetration half-life (t _1/2P) (serum to quarters), was found to be 36.89±11.14 min. The equivalent elimination half-life (t _1/2E) (quarters to serum) from the milk was 3.62±1.06 h and the peak thiamphenicol concentration in the milk was 23.09±3.42 µg/ml at 2.5±0.32 h.After intramuscular injection, the elimination half-life was 2.2±0.40 h, the absorption half-life was 4.02±1.72 min and the peak concentration in the serum was 30.90±5.24 µg/ml at 23±8.4 min. The bioavailability after intramuscular administration approached 100%. The penetration half-life was 50.59±6.87 min, the elimination half-life was 5.91±4.97 h and the mean peak concentration in the milk was 17.37±2.20 µg/ml at 3.4±0.22 h.Abbreviations AUC area under the concentration-time curve - CAP chloramphenicol - C _max peak concentration - IM intramuscular - IV intravenous - TAP thiamphenicol - t _1/2 distribution half-life - t _1/2 elimination half-life - V _c volume of central compartment - V _d volume of distribution     

Comparative pharmacokinetics and pharmacokinetic/pharmacodynamic analysis by nonlinear mixed‐effects modeling of cefquinome in nonpregnant,pregnant, and lactating goats after intravenous and intramuscular administration

Cefquinome is a fourth‐generation cephalosporin that is used empirically in goats. Different physiologic factors like pregnancy or lactation could determine the pharmacokinetic behavior of drugs in the organism. The objectives of this study are to (a) compare the pharmacokinetics of cefquinome after intravenous and intramuscular administration in adult nonpregnant (n = 6), pregnant (n = 6), and lactating goats (n = 6), at a dose of 2 mg/kg, with rich sampling by nonlinear mixed‐effects modeling, (b) conduct a pharmacokinetic/pharmacodynamic analysis to evaluate the efficacy of the recommended posology in goats with different physiological states, and (c) determine the optimal posology that achieve a PTA value ≥ 90%, taking into account a T > MIC ≥ 60% of a MIC value ≤ 0.25 µg/ml, in the different subpopulations of goats for both routes. Gestation significantly increased Ka and V1, while reduced F0, Cl, and Q. On the other hand, lactation significantly increased V1 and reduced Tk0. Cefquinome concentrations achieved in placental cotyledon, amniotic fluid, and fetal serum indicate a minimal penetration across the placental barrier. Moreover, milk penetration of cefquinome was minimal. The total body clearance of cefquinome for goats was 0.29 L kg^?1 hr^?1, that is apparently higher than the reported for cows (0.13 L kg^?1 hr^?1) and pigs (0.16 L kg^?1 hr^?1). So, the optimal dose regimen for cefquinome after intravenous and intramuscular administration required higher dose and frequency of administration compared with recommendations for cows or pigs. Therefore, 2 mg kg^?1 8 hr^?1 and 5 mg kg^?1 12 hr^?1 could be used for IV and IM routes, respectively, for the treatment of respiratory infections caused by P. multocida and M. haemolytica, but only 5 mg kg^?1 12 hr^?1 by both routes should be recommended for Escherichia coli infections.     

泌乳奶山羊非繁殖季节诱发发情研究

奶山羊具有明显的季节性发情的特点,在非繁殖季节里,泌乳母羊体内的催乳素水平要高于繁殖季节,从而抑制了卵巢的生理机能。本研究采用具有抑制催乳素分泌作用的溴隐亭(CB-154,Parlodel)药物来降低母羊体内的催乳素水平,配合使用促性腺激素,提高泌乳母羊的诱发发情率,使配种后不返情率达到80％(28/35)。     

日粮添加干玉米酒糟对泌乳奶牛干物质采食量、泌乳性能和瘤胃发酵的影响

文章旨在研究日粮中添加不同比例的干玉米酒糟对泌乳奶牛干物质采食量、泌乳性能和瘤胃发酵的影响。试验选择45头健康的中国荷斯坦奶牛,按照胎次、泌乳天数和产奶量进行区组设计,随机分配到3个处理组中,每组15头牛。对照组奶牛饲喂以玉米和豆粕为基础的日粮,不含有干玉米酒糟,试验1组和试验2组奶牛饲喂的日粮均以干玉米酒糟替代部分玉米和豆粕,替代比例分别为10%和20%(干物质基础)。预试期为2周,正试期为10周。试验结果表明,日粮添加干玉米酒糟显著提高了泌乳奶牛干物质采食量(P<0.05),而不同干玉米酒糟添加比例对奶牛的干物质采食量无显著影响(P>0.05)。日粮添加干玉米酒糟显著提高了泌乳奶牛的产奶量,且呈剂量依赖效应(P<0.05)。日粮添加干玉米酒糟对乳成分无显著影响(P>0.05),但由于产奶量的增加显著增加了乳中营养成分含量(P<0.05)。日粮添加干玉米酒糟改变了瘤胃发酵模式,降低了瘤胃液乙酸摩尔比值(P<0.05),增加了丙酸和丁酸摩尔比值(P<0.05),降低了瘤胃液NH3-N浓度。因此,可以使用干玉米酒糟替代部分玉米和豆粕来配合奶牛日粮,本试验中以20%的添加量较为合适。     

小鼠乳腺组织中β防御素1基因的克隆及其在妊娠期和泌乳期乳腺中的表达变化

β-防御素具有广谱的抗菌活性,并且是宿主固有免疫的重要参与者。为研究β-防御素1(β-defensin 1,Defb1)基因在不同泌乳时期的表达变化,以小鼠第4对乳腺组织为研究对象,用半定量RT-PCR法测定了小鼠妊娠期、泌乳期乳腺中Defb1基因的表达。结果表明,妊娠期Defb1的表达量呈上升趋势,且差异显著(P<0.05),而泌乳期却恰恰相反,随着泌乳的进行,Defb1的表达量逐渐降低,在泌乳18d时达到最低。