西门塔尔杂交母牛初乳成分及其对新生犊牛免疫的影响

牛的初乳是新生犊牛重要的营养来源,是新生犊牛获得被动免疫的重要物质基础。研究表明母牛的品种、年龄及初乳量都会对初乳的质量产生一定的影响。本文对西杂母牛初乳中常规营养成分和犊牛采食初乳后血清中免疫球蛋白、胰岛素含量变化进行了分析,结果表明:母牛产后2¹2 h与2412 h与24¹44 h相比,初乳中总乳固体、乳蛋白含量高,且差异显著(P<0.05);乳糖含量低,差异极显著(P<0.01)。母牛产后12 h,初乳中乳蛋白含量显著高于产后24 h、72 h(P<0.05)。犊牛采食初乳后24 h,血清中IgA含量最高;采食初乳后72 h,血清中IgA含量最高。犊牛出生后2 h以内采食初乳与出生后2144 h相比,初乳中总乳固体、乳蛋白含量高,且差异显著(P<0.05);乳糖含量低,差异极显著(P<0.01)。母牛产后12 h,初乳中乳蛋白含量显著高于产后24 h、72 h(P<0.05)。犊牛采食初乳后24 h,血清中IgA含量最高;采食初乳后72 h,血清中IgA含量最高。犊牛出生后2 h以内采食初乳与出生后2⁴ h采食初乳相比,采食初乳后24 h采食初乳相比,采食初乳后2¹44 h,血清中IgG含量较高。试验表明:母牛产后2144 h,血清中IgG含量较高。试验表明:母牛产后2¹2 h的初乳具有较高的营养价值,犊牛出生后212 h的初乳具有较高的营养价值,犊牛出生后2²4 h,小肠对IgG、IgA吸收能力较高,犊牛产后2 h以内采食初乳更有利于提高自身免疫力。     

补饲维生素E富硒舔砖对围产期奶牛健康的影响

为研究维生素E和硒对围产期奶牛健康的影响,试验选择年龄、胎次相同,预产期相近的中国荷斯坦奶牛40头,随机分成2组试验组为自由舔饲维生素E富硒舔砖组,对照组为不补饲维生素E富硒舔砖组,试验期90d(从预产前60d到产后30d).结果表明,试验组奶牛血液中维生素E的含量在产后12h和产后30d均显著高于对照组(P＜0.05),血液中硒的含量在产前30d、产后12h和产后30d均显著高于对照组(P＜0.01).试验组奶牛乳房炎、胎衣不下、子宫内膜炎疾病的发病率分别比对照组降低83.3%、80%、75%.     

移植骨髓间充质干细胞对乳腺炎模型大鼠血清中酶及抗体水平的影响

试验旨在研究乳房基底部移植骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)对乳腺炎大鼠血清中髓过氧化物酶(plup peroxidase,MPO)、乳过氧化氢酶(milk catalase,LP)及免疫球蛋白M(IgM)、免疫球蛋白A(IgA)、免疫球蛋白G(IgG)的影响。从70只SD正常雌性大鼠中随机选取5只,于产后72 h,即试验-1 d屠宰,作为正常对照,同时其余65只参照国内常用建立乳头管灌注内毒素的方法,从大鼠乳房基底部注入0.05 mL(50 μg)内毒素。乳腺炎模型建立成功1 d后,即试验0 d,随机选5只屠宰作为对照,同时将其余60只随机分为3组,即对照组(乳房基底部注射生理盐水50 μL)、抗生素组(乳房基底部注射抗生素50 μL(5000 U/侧))和移植BMSCs组(乳房基底部移植BMSCs 50 μL(1×10⁶个)),每组20只,于试验1、3、5和7 d各组分别屠宰5只,所有屠宰大鼠从心脏处采血制备血清,送检血清中MPO、LP、IgM、IgA和IgG含量。结果表明,治疗后各时间点移植BMSCs组血清中MPO含量均显著低于对照组(P<0.05),1和7 d时LP含量显著低于对照组(P<0.05)。1和5 d时移植BMSCs组IgA、IgG和IgM含量均显著高于对照组(P<0.05),7 d时IgG和IgM含量显著高于对照组(P<0.05),1和7 d时IgG含量、3和5 d时IgA含量及5 d时IgM含量均与抗生素组差异显著(P<0.05)。因此,BMSCs和抗生素都能降低乳腺炎大鼠血清中MPO和LP含量,提高IgM、IgA和IgG含量,且移植BMSCs组对抗体的总体作用效果比抗生素组显著。     

补饲开食料对哺乳期牦牛犊牛生长性能和血清指标的影响

试验研究补饲开食料对哺乳期牦牛犊牛生长性能及血清生化、免疫指标的影响。选取健康、出生日期及体重相近的10头1月龄牦牛犊牛(公),随机分为2组,每组5个重复。对照组犊牛饲喂代乳粉和苜蓿干草,试验组在对照组的基础上,补充饲喂开食料,两组的代乳粉饲喂量相同,且固体饲料的干物质采食量相近。结果显示,试验组牦牛犊牛总增重与平均日增重均极显著高于对照组(P<0.01)。试验组牦牛犊牛胸腺指数极显著高于对照组(P<0.01)。试验组牦牛犊牛血清谷草转氨酶(AST)活性、甘油三酯(TG)含量均显著低于对照组(P<0.05),总胆固醇(TC)含量极显著低于对照组(P<0.01)。试验组牦牛犊牛血清白蛋白(ALB)极显著低于对照组(P<0.01),免疫球蛋白G(IgG)、免疫球蛋白M(IgM)、白细胞介素4(IL-4)、白细胞介素10(IL-10)含量显著高于对照组(P<0.05),免疫球蛋白A(IgA)、白细胞介素2(IL-2)、白细胞介素6(IL-6)、和肿瘤坏死因子α(TNF-α)含量均极显著高于对照组(P<0.01)。研究表明,补饲开食料可以改善哺乳期牦牛犊牛的生长性能,有助于机体的蛋白质合成,提升牦牛犊牛早期的免疫应答水平,促进哺乳期牦牛犊牛的生长发育。     

日粮添加酵母硒对绵羊的生长性能、组织硒沉积和免疫功能的影响

为了研究日粮添加酵母硒对育肥期绵羊生长功能、组织硒沉积量和免疫功能的影响,选择体重、年龄相近的育肥羊200只,随机分成2组,每组100只,对照组和试验组饲粮中分别添加0.4 mg/kg(以硒计)的亚硒酸钠或酵母硒,预试期10 d,正试期为60 d。结果显示：日粮中添加酵母硒极显著提高了育肥羊60 d体重、血清免疫球蛋白(IgA、IgM、IgG)含量、血清白介素-8(IL-8)含量(P<0.01),显著提高血清IL-4、IL-13、肿瘤坏死因子-α(TNF-α)和γ-干扰素(INF-γ)含量(P<0.05);酵母硒极显著提高了羊后腿肌肉中硒含量(P<0.01),但颈部肌肉差异不显著(P>0.05)。结论：酵母硒能提高绵羊组织硒含量,有效改善绵羊的生长性能和免疫指标。     

布拉氏酵母菌对哺乳犊牛腹泻率、血清免疫、抗氧化指标及粪便微生物的影响

试验旨在探讨布拉氏酵母对犊牛腹泻率、血清免疫、抗氧化指标及粪便微生物的影响。试验选取了48头新生重(38.16±3.73)kg相近且健康状况良好的中国荷斯坦犊牛,随机分成四组,每组12头且公母对半。各处理组饲粮中分别添加0(对照)、1、3、5 g/(d·头)的布拉氏酵母。试验周期为42 d。结果表明:1～21 d时,3、5 g/(d·头)试验组犊牛的粪便评分显著低于对照组(P0.05),且1、3、5 g/(d·头)试验组犊牛腹泻率比对照组分别降低了35%、52%和42%(P0.05)。试验第21 d,3、5 g/(d·头)试验组犊牛的血清免疫球蛋白A(IgA)、免疫球蛋白M(IgM)、免疫球蛋白G(IgG)、白介素-2(IL-2)和白介素-4(IL-4)含量显著高于对照组(P0.05);对照组犊牛的血清白介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)含量显著高于其他各试验组(P0.05);试验第21 d和42 d,3、5 g/(d·头)试验组犊牛的血清丙二醛(MDA)含量显著低于对照组(P0.05)。试验第21 d,3、5 g/(d·头)试验组犊牛粪便的大肠杆菌数量显著低于对照组(P0.05),乳酸菌数量显著高于对照组(P0.05);试验第42 d,3、5 g/(d·头)试验组犊牛粪便的乳酸菌数量显著高于对照组(P0.05)。可见,在犊牛早期(1～21 d)饲粮中补充布拉氏酵母可以通过提高肠道有益菌的数量,抑制肠道致病菌的定植,从而降低犊牛的腹泻率、提高机体的抗氧化能力和免疫力,3 g(1.38×10~(10)CFU/g)布拉氏酵母的添加效果最佳。     

甘露寡糖添加方式对哺乳期犊牛生长性能、粪便菌群及血清免疫指标的影响

本试验旨在研究甘露寡糖的不同添加方式对哺乳期犊牛生长性能、粪便菌群及血清免疫指标的影响。试验选用日龄、体重相近,健康状况良好的新生荷斯坦公犊牛20头,随机分为4组,每组5个重复。Ⅰ组（对照组）不添加甘露寡糖;Ⅱ组在牛奶中添加5 g甘露寡糖;Ⅲ组在开食料中添加5 g甘露寡糖;Ⅳ组在牛奶和开食料中各添加2.5 g甘露寡糖。试验期56 d。结果表明：①在整个试验周期内,犊牛体长与体躯指数的组间差异不显著（P>0.05）。②整个试验周期内,各试验组犊牛平均干物质日采食量、平均日增重均高于Ⅰ组;各试验组料重比均低于Ⅰ组;且Ⅱ组试验效果优于其他两个试验组。③试验第21天时,各试验组犊牛粪便中双歧杆菌数均显著高于Ⅰ组（P<0.05）,且Ⅱ组显著高于其他两个试验组（P<0.05）;各试验组粪便中大肠杆菌数均显著低于Ⅰ组（P<0.05）,且以Ⅱ组为最低。试验第56天时,各试验组粪便双歧杆菌数均高于Ⅰ组,各试验组粪便中大肠杆菌数均低于Ⅰ组（P>0.05）,且Ⅱ组大肠杆菌数最低。④试验第21天时,Ⅱ组血清中IgA浓度显著高于Ⅰ组（P<0.05）,Ⅲ、Ⅳ组血清中IgA浓度略高于Ⅰ组（P>0.05）;IgG变化规律与IgA相似;Ⅳ组血清中IgM浓度显著高于Ⅰ组（P<0.05）,Ⅲ组在数值上略低于Ⅰ组（P>0.05）。试验第56天时,各试验组血清中免疫球蛋白含量均高于Ⅰ组（P>0.05）。综上所述,在犊牛饮用奶中添加甘露寡糖对于提高动物的生长性能及机体的抵抗力的效果优于其他两种方案。     

富硒乳酸菌中药制剂对育肥猪免疫、抗氧化能力的影响

本试验旨在研究富硒乳酸菌中药制剂(LSTCM)对育肥猪免疫、抗氧化能力的影响。选取日龄相近、体重(57±1.50)kg、体况良好的杜×长×大三元杂交育肥猪60头,分为4个组,每组3个重复,每重复5头猪。对照组饲喂基础日粮,试验组分别在基础日粮中添加0.1%、0.3%、0.5%的LSTCM(硒含量为100 mg/kg)。预试期10 d,正试期60 d。结果表明:与对照组相比,0.3%、0.5%LSTCM组IgA含量极显著提高,而IgG及IgM含量显著提高;与对照组相比,0.3%LSTCM组血清、肌肉、肝脏中总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活性均提高(P<0.01),肾脏中T-AOC、SOD活性均提高(P<0.01),GSH-Px活性提高(P<0.05),血清、肌肉、肾脏中丙二醛含量均降低(P<0.01),肝脏中降低(P<0.05)。综上所述,富硒乳酸菌中药制剂能显著提高育肥猪免疫能力以及血清及组织的抗氧化能力。     

日粮添加双歧杆菌对柴达木绒山羊血清生化、免疫和抗氧化指标的影响

为了探讨日粮添加双歧杆菌对柴达木绒山羊血清生化、免疫和抗氧化指标的影响,选择48只年龄、体况接近的健康柴达木绒山羊,随机分成2组(对照组、试验组),每组3个重复,每个重复8只。对照组饲喂基础日粮,试验组在基础日粮中添加5×10⁶ CFU/g的双歧杆菌,预试期10 d,正式期60 d。第30 d、60 d清晨空腹颈静脉采血,提取血清检测血液生化、免疫、抗氧化相关指标。结果表明,在血清生化指标中,第30 d,试验组GH含量显著高于对照组(P<0.05);第60 d,试验组ALT、ALP、GH、INS、Urea含量显著低于对照组(P<0.05)。在血清免疫指标中,第30 d,试验组IgA、IgG、IgM、IL-4含量显著高于对照组(P<0.05),GLB、IL-1beta含量虽然高于对照组,但无显著差异(P>0.05);第60 d,试验组GLB、IL-1beta、IL-2、IL-4、IL-6含量显著低于对照组(P<0.05)。在抗氧化指标中,第30 d,试验组血清SOD、GSH-Px含量高于对照组,且MDA含量低于对照组,但均无显著差异(P...     

自制复方中草药片剂对奶牛产后机能恢复和免疫功能的影响

为了研究自制复方中草药片剂对奶牛产后机能恢复及免疫功能的影响,试验以临产的40头荷斯坦奶牛为试验对象,对照组20头、试验组20头。对照组不进行药物投喂,试验组于产后当天开始投喂复方中草药片剂,每天投喂2次,每次每头35片,连续用药6 d,观察并记录奶牛的体况恢复情况,并分别于产后第0,3,6天对对照组和试验组奶牛进行尾静脉采血,分离血清测定IgA、IgG、IgM免疫指标。结果表明:与对照组比较,试验组奶牛产后胎衣不下的发生率降低了75%,恶露排净天数提前了3 d,发情期提前了4 d,乳房炎的发病率下降33.3%,第一次配种受孕率提高8%。产后奶牛体内抗体水平在3 d后IgA浓度提高了20.61%(P0.05),IgG浓度差异不明显(P0.05),IgM浓度提高16.46%(P0.05);在6 d后IgA浓度提高了30.91%(P0.01),IgG浓度提高了22.22%(P0.05),IgM浓度提高了20.56%(P0.05)。说明自制复方中草药片剂不仅可以明显提高产后奶牛机体免疫力,而且可以促进产后奶牛机能的快速恢复,对奶牛产后疾病的防治和保健起到了很好的疗效。     

Effects of oral vitamin E supplementation during late gestation in beef cattle that calved in late winter and late summer

OBJECTIVE: To determine effects of breed and oral vitamin E supplementation during late gestation on serum vitamin E and IgG concentrations in beef cows that calved in late winter and late summer and in neonatal calves. ANIMALS: 73 Angus and 43 Hereford primiparous and multiparous cows and their calves. PROCEDURE: Cows in groups that were homogeneous regarding breed and age distribution were randomly allotted to groups that were orally supplemented (n = 59) or not supplemented (57) with vitamin E beginning 30 days prior to onset of 65-day calving seasons. Supplemental vitamin E was provided in a vitamin-mineral mix offered free-choice until parturition. RESULTS: Cows that calved in late winter and were supplemented orally with vitamin E had higher serum vitamin E concentrations at calving and after calving than did unsupplemented cows; differences between groups before calving were not significant. Calves from supplemented multiparous cows had higher vitamin E concentrations than did calves from unsupplemented cows. Winter-born calves from supplemented Hereford cows had heavier 205-day adjusted weaning weights than did winter-born calves from unsupplemented Hereford cows. Supplementation did not affect vitamin E or IgG concentrations in the herd that calved in late summer and did not affect calf growth. CONCLUSIONS AND CLINICAL RELEVANCE: Oral vitamin E supplementation during late gestation may be economically beneficial in certain cow-calf operations in which late-gestation cows are consuming stored forages.     

Changes of vitamin E status of periparturient dairy cows and newborn calves

Eleven primiparous Holstein Friesian and their crossbred calves (F1, Japanese Black cattle × Holstein Friesian) and 10 multiparous Holstein Friesian and their Holstein Friesian calves were used to evaluate vitamin E status in periparturient period. Plasma α‐tocopherol (α‐toc) concentrations of the multiparous cows were significantly higher than those of the primiparous cows from 60 days before expected calving to 90 days of lactation (P < 0.05). The multiparous cows had a further decrease in the concentrations of α‐toc and total lipid in plasma to the calving than the primiparous cows. Colostrum α‐toc concentrations in multiparous cows were significantly higher than those of the primiparous cows (P < 0.05). Plasma α‐toc concentrations of calves borne by the multiparous cows were significantly higher than those of the primiparous cows at 5 days of age (P < 0.05). Plasma α‐toc concentrations of calves were highest at 5 and 15 days of age in the calves borne by the multiparous and primiparous cows, respectively, and decreased thereafter till 90 days of age. The higher vitamin E status of multiparous cows over primiparous cows might have reflected nutritional composition in the rations. Their calves afforded higher plasma α‐toc levels after birth because of more α‐toc transfer via placenta and more α‐toc secretion in the colostrums thereafter. Plasma α‐toc concentrations of the calves might have decreased as the calves became dependent upon the solid feed of low vitamin E content.     

Effects of prepartum energy intake on steroids during late gestation and on cow and calf performance

At 50 d prior to predicted calving, 37 multiparous Angus cows were grouped by sire of mating, age and weight of cow and placed on either a high energy (HE, n = 19) diet or a moderate energy (ME, n = 18) diet. Objectives were to determine the effect of prepartum nutrition on: prepartum serum concentrations of estrone (E1), estrone sulfate (E1SO4) and progesterone (P4); pre- and postpartum cow body weight changes; calf birth weight and cow and calf postpartum performance. The ME cows were group-fed Coastal bermudagrass hay ad libitum and dormant pasture; HE cows were group-fed 2.7 kg ground corn X head-1 X d-1 in addition to the ME treatment. Both groups were combined and fed identically after calving. Cows fed HE were heavier (P less than .01) than cows fed ME at d 10 prepartum and their calves were heavier (P less than .05) at birth and weaning than calves from cows fed ME. Serum E1 concentrations were not significantly different between groups, but serum E1SO4 was higher (P less than .01) at d 10 prepartum in ME cows compared with HE cows. Serum P4 concentrations of ME cows were higher (P less than .05) than those of HE cows. Cow body weights were greater (P less than .01) for the HE group than for the ME group during the first 6 mo postpartum. Cow rebreeding performance was identical for both groups.     

Changes in pelvic conformation and peripheral estrone concentrations in pre- and post-partum beef cows

An experiment was conducted to investigate the temporal relationship of peripheral estrone (E1) concentration to changes in the size of the pelvic opening preceding and immediately following parturition. Twenty-six multiparous beef cows were observed from approximately 50 d prepartum to 7 d postpartum. Blood samples were collected at 7 d intervals preceding calving and at 1, 3 and 7 d following for E1 quantitation. Estimates of pelvic opening area were made at the time of blood sampling. Peripheral E1 concentrations were elevated beginning at approximately 25 d prepartum. Dams bearing male fetuses had greater (P less than 0.01) concentrations of E1 than did dams with female fetuses. Calf birth weight was correlated (r = 0.44, P less than 0.01) with E1 levels from 10 d prepartum through parturition. Postpartum pelvic area was greater for cows giving birth to male calves, with no significant differences for calf birth weights by sex. Correlations were observed between E1 concentration, and pelvic area measured from 50 d prepartum to 7 d postpartum (r = 0.26, P less than 0.01), 10 d prepartum to calving (r = 0.42, P less than 0.01), and from calving to 7 d postpartum (r = 0.33, P less than 0.01). Percentage increase in E1 concentration from 50 d prepartum to calving was significantly correlated (r = 0.75, P less than 0.01) to percentage pelvic area increase over the same period. A correlation also exists between maternal E1 concentrations and fetal sex and pelvic area. In summary, the increased estrogen concentrations in cows with male calves may facilitate pelvic spread, resulting in a larger pelvic opening.     

Effect of iodine,selenium and cobalt rumen boluses given to dry dairy cows on the immunoglobulin and thyroid hormone status of calves

The objective was to determine the effect of rumen boluses containing 6800 mg iodine, 1000 mg selenium and 1000 mg cobalt given to dry dairy cows on the efficiency of colostral immunoglobulin G (IgG) absorption in calves. Thirteen cows received the bolus approximately 58 days before calving. A further 12 cows received no bolus and were used as controls. The cows were housed as one group. Calves were prevented from suckling for the first 24 h of life, and were given three feeds of a fixed quantity of colostrum. At 24 h, the average plasma concentrations of IgG in the calves were 15.5 and 13.4 g/L for the control and bolus groups, respectively; these were not significantly different (P = 0.212). Bolus treatment was associated with higher levels of free and total tri‐iodothyronine (T3) and thyroxine (T4) in the dams (all P < 0.001), although it had no effect on thyroid hormone levels in the calves. There were nevertheless positive and negative relationships between the efficiency with which colostral IgG was absorbed at 24 h and, respectively, total T3 at 24 h (P < 0.05) and total T4 at 1 h of age (P < 0.05). The underlying basis for these relationships remains to be established.     

全株玉米青贮、谷草和羊草组合全混合日粮饲喂干奶前期奶牛对其围产期生产性能和血液生化及免疫指标的影响

在研究不同比例全株玉米青贮、谷草和羊草组合日粮饲喂干奶前期奶牛对其围产期生产性能和血液生化及免疫指标的影响。选择健康、体况一致的干奶前期荷斯坦奶牛45头,根据体重、胎次及预产期接近(P>0.05)的原则将奶牛随机分为试验A、B和C组,每组15头。分别以精料、全株玉米青贮、谷草和羊草16∶24∶30∶30(A组)、16∶24∶45∶15(B组)和16∶24∶60∶0(C组)比例配合日粮饲喂。产前2周将3组试验牛转入围产牛群,3个试验组开始饲喂场内同一围产前期和新产牛日粮。试验期88 d。结果表明:1)与C组相比,B组在产后1、2和3周的干物质采食量分别提高10.46%(P<0.05)、7.79%(P<0.05)和5.65%(P<0.05)。除产后1周外,产后2、3周B组的奶牛体况评分分别比C组高6.60%(P<0.05)和9.06%(P<0.05)。2)各试验组的犊牛初生重差异不显著(P>0.05)。试验A、B组初乳免疫球蛋白G(IgG)含量分别比C组提高10.82%(P<0.01)和18.07%(P<0.01)。3)与C组相比,B组产后21 d产奶量提高9.00%(P<0.05),乳非脂固形物率提高2.83%(P<0.05),乳蛋白率提高10.59%(P<0.05),乳糖率提高5.64%(P<0.05)。各试验组间乳脂率和尿素氮无显著差异(P>0.05)。4)分娩当天和产后21 d,B组的血清甘油三酯含量显著低于A和C组(P<0.05),B组的血糖含量显著高于A和C组(P<0.05), B组的血清尿素氮和胰岛素显著低于C组(P<0.05),B组的胰岛素样生长因子I(IGF-I)和总蛋白显著高于C组(P<0.05);在产前7 d和分娩当天,B组的血清免疫球蛋白A(IgA)、免疫球蛋白B(IgM)和IgG显著高于C组(P<0.05);在产后21 d,B组的血清IgM和IgG含量显著高于C组(P<0.05);产前7 d和分娩当天,B组瘦素显著高于C组,而B组的血清非酯化脂肪酸(NEFA)含量显著低于C组(P<0.05);在产前7 d、分娩当天和产后21 d,B组的胆固醇均显著低于C组(P<0.05),B组的血清白蛋白含量显著高于C组,B组谷草转氨酶(AST)和谷丙转氨酶(ALT)也显著低于C组(P<0.05)。各试验组间β-羟丁酸无显著差异(P>0.05)。综合分析,干奶前期饲粮组成和养分水平可影响围产期奶牛的机体代谢和生产性能。在本试验条件下,干奶前期奶牛日粮中精料、全株玉米青贮、谷草和羊草的适宜比例为16∶24∶45∶15。     

Vitamin E and selenium concentrations in month-old beef calves.

Three groups of beef cow and calf pairs were studied to determine plasma vitamin E and blood selenium (Se) concentrations of calves at 1 month old. Group 1 was managed on irrigated pasture and calves received no Se/vitamin E injections at birth. Group 2 was managed on irrigated pasture, and the calves were injected with Se/vitamin E at birth. Group 3 was managed on dry foothill grasslands, and these cows were supplemented with 56.3 mg vitamin E and 3 mg Se daily, and the calves received a Se/vitamin E injection at birth. The plasma concentration of vitamin E in group 1 and 2 cows (9.5 +/- 1.24 and 8.43 +/- 1.0 microg/ml, respectively) was significantly higher than that of the group 3 cows (2.28 +/- 0.42 microg/ml; P < 0.05). The blood Se concentrations in group 3 cows (169 +/- 37 ng/ml) were significantly higher than those in group 1 and 2 cows (36.4 +/- 15.9 and 31.1 +/- 12.5 ng/ml, respectively; P < 0.05). Calf Se was highly correlated to cow Se (r = 0.965), and calf vitamin E was moderately correlated to cow vitamin E (r = 0.605). Calf vitamin E concentrations were consistently lower than cow vitamin E concentrations, and many values would be considered deficient.     

奶牛不同生理阶段血清微量元素含量和氧化状态

选择3～4月龄犊牛、后备母牛和成年母牛(产奶后期、产前及产后1月内).测定了血清Se、Cu、Zn、Mn、Fe含量厦谷胱甘肤过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量.结果表明,除Zn含量外,所测元素含量犊牛明显低于后备母牛和成年牛(P<0.05或P<0.01),后备母牛和成年牛之闻差异不显著(P>0.05),血清Se含量在产奶后期和产前明显下降(P<0.05),血清Cu、Mn含量在产后1月内有降低的趋势,但与产前相比均差异不显著(P>0.05);所测血清氧化状态指标与年龄无明显关系,在妊娠末期和泌乳早期发生改变,血清CAT、GSH-Px、SOD活性和MDA含量在产前和产后1月内最高.表明犊牛上述所测指标最低,奶牛产前和泌乳早期血清微量元素含量和氧化状态失衡.     

The impact of cow nutrition in the dry period on colostrum quality and immune status of calves

The objective of the study was to evaluate the effect of energy contents in a dry period diets in "7+1" feeding strategy of dry cow including 7 weeks of the dry period (far-off) and 1 week of a close-up period, on colostrum quality and the immune status of calves. Forty Holstein multiparous cows were dried at 56d before the expected date of calving and were assigned to the higher energy diet group (HE; 0.69 UFL/kg DM, NDF 52% DM), or the lower energy diet group (LE; 0.61 UFL/1kg DM, NDF 56% DM). From -7d to the expected calving date up to 21 d of lactation, all cows were fed the same fresh, lactation diet. Samples of colostrum were collected within 2h after parturition and its density, dry matter content and concentrations of immunoglobulins, fat, protein, lactose, urea and somatic cell counts were measured. Calves were weighed 2 h after calving and on the 21d of life. On 3d and 21d of calves' life blood samples were collected and the concentration of IgG, IgA, IgM, insulin-like growth factor 1 (IGF-1) as well as total protein and albumin concentrations were determined. Treatments had no significant effect on composition of colostrum and serum immunoglobulins and IGF-1 concentration. In both groups the weight of calves at birth was similar, still daily body weight gain during 21 day of rearing period in HE group was higher than in the LE group (P=0.05).     

Reproductive performance of Gyr cows: the effect of weaning age of calves and postpartum energy intake

Two nutritional levels following parturition and five weaning ages for the calf were evaluated to study their effect of reproduction in Gyr cows in the savannas of West Central Brazil (Campos Cerrados). Early weaning of calves reduced postpartum weight losses and shortened the postpartum interval to conception. Energy level did not affect cow weight at weaning or conception, the number of days from parturition to first estrus or the number of matings/conception; however, the postpartum period to conception was reduced (116 vs 160 d; P less than .05) for cows on the higher energy diet. Weaning age significantly affected postpartum weight loss in cows. Six months after calving, cows that nursed calves for 1 mo were 89 kg heavier than those that nursed calves for 6 mo (384 vs 295 kg; P less than .05). Cows that were nursed for 1 mo returned to estrus at an average of 40 d postpartum, which was 23 d earlier (P less than .05) than the average of the other groups nursed for longer periods of time. There was no significant difference in the postpartum period to conception among cows that had their calves weaned at 1 mo, 3 mo and cows which were nursed twice daily beginning 30 d after parturition (57, 94 and 97 d, respectively), but was less (P less than .05) for cows nursed for 5 or 6 mo (212 and 231 d, respectively). The results show that Gyr cattle are genetically capable of responding reproductively to improve nutrition and reduced lactation stress achieved through early weaning or controlled nursing.