低聚果糖对早期断奶犊牛肠黏膜和免疫指标的影响

选用同一牛场的荷斯坦公犊牛35头,研究低聚果糖(FOS)对早期断奶犊牛肠黏膜形态及免疫指标的影响。结果表明:4g/(d·头)FOS组(E组)、6g/(d·头)FOS组(F组)、常规哺乳组犊牛肠绒毛高度、固有膜厚度、小肠黏膜DNA浓度均显著高于早期断奶对照组(P<0.05);添加FOS对小肠黏膜RNA含量有增加趋势;犊牛70日龄时,E、F组IgG、IgA含量极显著高于早期断奶对照组(P<0.01),显著高于其他各组(P<0.05);早期断奶对照组IgG、IgA含量显著低于其他各组(P<0.05)。说明FOS能防止早期断奶犊牛肠道萎缩,维持肠道的正常形态结构,提高犊牛免疫性能。     

复合多肽对早期断奶仔猪生长性能、血液理化指标和肠道主要菌群数量的影响

本试验旨在探究复合多肽对早期断奶仔猪生长性能、血液理化指标和肠道主要菌群数量的影响。将90头21日龄断奶的"杜×长×大"三元杂交仔猪按体重相近、公母各占1/2的原则随机分为3组,每组3个重复,每个重复10头猪。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加0.5%和1.0%的复合多肽,试验期30d。在试验的第30天测定断奶仔猪的各项生长性能指标、血液中各项理化指标以及肠道菌群数量。结果表明:与对照组相比,饲粮中添加0.5%和1.0%的复合多肽均可以增加断奶仔猪的平均日增重和平均日采食量,降低料重比,但差异不显著(P>0.05);饲粮中添加0.5%的复合多肽显著提高血清总抗氧化能力(P<0.05),添加1.0%的复合多肽显著降低血清一氧化氮含量(P<0.05);饲粮中添加0.5%和1.0%的复合多肽均可以在一定程度上提高血清免疫指标,且1.0%的添加水平能显著提高血清白细胞介素-2、甲状腺素、胰岛素和胃泌素的含量(P<0.05);饲粮中添加0.5%的复合多肽可以显著降低肠道中大肠杆菌数量,提高乳酸杆菌的数量(P<0.05)。由此可见,饲粮中添加0.5%和1.0%的复合多肽均可以在一定程度上提高断奶仔猪生长性能以及抗氧化能力,提高血清中各项免疫指标以及激素含量,并且添加0.5%的复合多肽能显著提高肠道中乳酸杆菌数量,降低大肠杆菌数量。     

一种复方中药对断奶至2月龄肉兔生长发育、血清生化指标和肠道发育的影响

试验为研究复方中药对断奶至2月龄肉兔生长性能、血清指标、免疫机能及肠道发育的影响。选用体重(713±50)g断奶肉兔120只,随机分2组,分别饲喂基础日粮和添加复方中药的日粮,预试期7 d,正试期23 d。结果表明:日粮中添加复方中药能显著提高平均日增重(P0.05)和平均日采食量(P0.05),并显著降低料肉比(P0.05);能显著降低血清尿素氮含量(P0.05),显著提高血清IgG含量(P0.05)和血清总抗营养化能力(P0.05);能显著降低盲肠中大肠杆菌含量(P0.05)、提高乳酸菌含量(P0.05)。结果表明,日粮中添加复方中药能在一定程度上提高肉兔的生长性能,提高机体氮沉积,增强机体免疫力和抗氧化能力,并改善肠道微生物区系,有利于动物肠道健康。     

饲粮添加苹果果胶寡糖对断奶大鼠生长性能、抗氧化能力和肠道健康的影响

本研究旨在探讨饲粮添加苹果果胶寡糖(apple pectic oligosaccharide,APOS)对断奶大鼠生长性能、抗氧化能力和肠道健康的影响。试验选取24只健康的断奶Wistar大鼠,按照体重相近的原则分为2个处理,分别饲喂基础饲粮和添加800 mg/kg APOS的饲粮,试验期为14 d。结果表明:饲粮添加APOS显著提高了断奶大鼠平均日增重和平均日采食量(P0.05),显著降低了料重比(P0.05);饲粮添加APOS可显著提高断奶大鼠血清总抗氧化能力(P0.05),降低血清中丙二醛的含量(P0.05);饲粮添加APOS还可显著提高空肠黏膜绒毛高度/隐窝深度值(P0.05);此外,饲粮添加APOS也提高了盲肠食糜中乳酸菌和双歧杆菌的数量(P0.05),降低了盲肠食糜中大肠杆菌的数量(P0.05)。综上所述,在断奶大鼠的饲粮中添加APOS可以提高其生长性能,而这可能源于其改善了大鼠抗氧化能力、空肠黏膜形态和肠道菌群结构。     

富铁产朊假丝酵母对断奶仔猪生长性能、血液指标和肠道形态的影响北大核心

试验旨在研究富铁产朊假丝酵母对断奶仔猪生长性能、血液指标和肠道形态的影响。选择90头(7.86±0.54)kg、体况相近的健康28日龄“杜×长×大”断奶仔猪,随机分为2组,每组9个重复,每个重复5头猪。对照组(CON组)仔猪饲喂基础日粮+硫酸亚铁(含铁104 mg/kg),试验组(CU组)仔猪饲喂基础日粮+富铁产朊假丝酵母(含铁104 mg/kg),试验期28 d。结果显示,富铁产朊假丝酵母对断奶仔猪生长性能影响不显著(P>0.05)。与CON组相比,CU组仔猪血液白细胞总数、嗜碱性粒细胞百分含量显著提高(P<0.05);血清免疫球蛋白A和免疫球蛋白G含量显著提高(P<0.05),肿瘤坏死因子-α含量显著降低(P<0.05);血清铁含量显著提高(P<0.05),血清总铁结合能力和铜蓝蛋白活性显著降低(P<0.05)。与CON组相比,CU组断奶仔猪血清过氧化氢酶、细胞色素氧化酶、谷胱甘肽过氧化物酶和总超氧化物歧化酶活性显著提高(P<0.05),血清丙二醛含量显著降低(P<0.05);CU组断奶仔猪十二指肠、空肠绒毛高度和绒毛高度/隐窝深度值显著提高(P<0.05),隐窝深度显著降低(P<0.05)。研究表明,富铁产朊假丝酵母替代无机铁,可以改善仔猪机体铁代谢、抗氧化和免疫功能,有利于维护肠道形态。     

不同水平黄芪多糖对早期断奶犊牛生长性能及抗氧化能力的影响

为了探讨不同水平黄芪多糖对早期断奶犊牛生长性能及抗氧化指标的影响,试验选择健康、体重相近的早期断奶母犊牛30头,随机均分为对照组、试验A组和试验B组,对照组日粮中不添加黄芪多糖,试验A组和试验B组在日粮中分别添加5 g/头和10 g/头的黄芪多糖,正试期为60 d,测定早期断奶犊牛的生长性能并采集血液检测超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和丙二醛(MDA)含量。结果表明:日粮中添加5 g/头和10 g/头的黄芪多糖均能显著提高早期断奶母犊牛的采食量和日增重(P0.05),降低发病率,10 g/头的黄芪多糖改善机体的抗氧化能力效果优于5 g/头(P0.05)。说明在早期断奶犊牛日粮中添加5～10 g/头的黄芪多糖可以降低早期断奶犊牛的应激危害,提高其生长性能和抗氧化能力。     

牛至油对断奶～2月月龄肉兔生长发育长发育、血清生化及肠道发育的影响

本文旨在研究肉兔日粮中添加牛至油对断奶~2月龄肉兔生长性能、血清指标、免疫机能及肠道发育的影响。选用平均体重为(713±50 g)的断奶肉兔80只,随机分成2组,分别饲喂基础饲粮(对照组)和添加5%牛至油素的日粮。预试期7 d,正试期23 d。试验结果表明:日粮中添加牛至油能显著提高平均日采食量和平均日增重(P0.05),显著降低料肉比(P0.05)。日粮中添加牛至油能显著降低血清尿素氮含量(P0.05),显著提高血清Ig G含量(P0.05),显著降低盲肠中大肠杆菌含量和乳酸菌含量(P0.05)。综合考虑本试验所测指标,日粮中添加牛至油能在一定程度上提高肉兔的生长性能,提高机体氮沉积,增强机体免疫力,并能改善肠道微生物区系,有利于动物肠道健康。     

竹叶和茶叶渣对断奶犊牛生长性能、消化代谢及血清抗氧化和免疫指标的影响

本试验旨在研究全混合日粮(TMR)中相同中性洗涤纤维(NDF)水平下,以竹叶或茶叶渣替代苜蓿对断奶犊牛生长性能、消化代谢及血清抗氧化和免疫指标的影响。按照随机区组设计将45头105日龄的荷斯坦公犊牛分成3组,每组15头犊牛,分别饲喂苜蓿(AH组)、竹叶(BL组)或茶叶渣(TR组)为主要NDF来源的TMR。预试期15 d,正试期60 d。结果表明:1)180日龄时,TR组的体重显著低于AH组(P<0.05);试验期间,BL组与AH组之间的平均日增重、干物质采食量和料重比无显著差异(P>0.05)。2)与AH组相比,BL组的干物质(DM)和酸性洗涤纤维(ADF)表观消化率显著降低(P<0.05),而有机物(OM)和NDF表观消化率差异不显著(P>0.05);TR组的NDF表观消化率显著提高(P<0.05),而DM、OM和ADF表观消化率差异不显著(P>0.05)。3)与AH组相比,BL组的尿能、总能消化率、总能代谢率和消化能代谢率显著降低(P<0.05)。4)与AH组相比,BL组的尿氮显著提高(P<0.05),氮沉积率显著降低(P<0.05);TR组的粪氮显著提高(P<0.05),氮表观消化率显著降低(P<0.05)。5)与AH组相比,BL和TR组的血清谷胱甘肽过氧化物酶(GSH⁃Px)和过氧化氢酶(CAT)活性显著降低(P<0.05),血清免疫球蛋白A(IgA)、丙二醛(MDA)含量显著升高(P<0.05);BL组的血清总抗氧化能力(T⁃AOC)显著降低(P<0.05)。由此可见,与饲喂苜蓿饲粮相比,饲喂竹叶饲粮的断奶犊牛生长性能及OM、NDF表观消化率相近,但能量和氮的利用率降低;饲喂茶叶渣饲粮的断奶犊牛能量利用率相近,而NDF表观消化率显著提高,生长性能和氮的利用率降低;饲喂竹叶饲粮和茶叶渣饲粮的断奶犊牛血清IgA含量显著提高,抗氧化能力降低。综上所述,断奶犊牛阶段可以用竹叶(24.38%)替代苜蓿作为饲粮的粗饲料。     

饲粮中添加香菇多糖对断奶大鼠生长性能、抗氧化能力和肠道健康的影响

本研究旨在探讨饲粮中添加香菇多糖对断奶大鼠生长性能、抗氧化能力和肠道健康的影响。试验选取20只健康的断奶Wistar大鼠,按照体重相近的原则分为2个组(每组10只),分别饲喂基础饲粮和添加了84 mg/kg香菇多糖(香菇多糖有效含量为30%)的试验饲粮。试验期为21 d。结果表明:饲粮中添加84 mg/kg香菇多糖显著提高了断奶大鼠的平均日增重和平均日采食量(P0.05),显著降低了料重比(P0.05);饲粮中添加84 mg/kg香菇多糖显著提高了断奶大鼠血清和空肠的总抗氧化能力(P0.05),不同程度降低了血清(P0.05)和空肠(P=0.08)丙二醛含量;饲粮中添加84 mg/kg香菇多糖显著提高了断奶大鼠空肠黏膜绒毛高度和绒毛高度/隐窝深度(P0.05);此外,饲粮添加84 mg/kg香菇多糖提高了断奶大鼠盲肠食糜中乳酸菌的数量(P=0.07),显著降低了盲肠食糜中大肠杆菌的数量(P0.05),并显著提高了盲肠食糜中乙酸、丙酸、丁酸和总挥发性脂肪酸的含量(P0.05)。综上所述,在断奶大鼠饲粮中添加84 mg/kg香菇多糖(香菇多糖有效含量为30%)可以改善其抗氧化能力、空肠黏膜形态结构和盲肠菌群结构,进而提高生长性能。     

饲粮中添加山梨酸对断奶仔猪生长性能、血清生化指标及相关基因mRNA表达的影响

本试验旨在研究饲粮中添加山梨酸(SA)对断奶仔猪生长性能的影响及其机制。试验选用28日龄纯种大约克断奶仔猪180头,随机分成4组,每组3个重复,每重复15头猪(8阉公、7母)。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加0.050%、0.125%和0.200%的SA,观察其对断奶仔猪生长性能、小肠绒毛形态、器官指数、血清生化指标及相关基因mRNA表达量的影响。预试期为7 d,试验期为42 d。结果表明:1)与对照组相比,饲粮中添加0.200%SA能显著提高断奶仔猪56和77日龄的体重和全期的平均日增重(P<0.05),但对器官指数和小肠绒毛形态无显著影响(P>0.05)。2)0.200%SA组的血清总蛋白、低密度脂蛋白、胰岛素样生长因子-Ⅰ(IGF-Ⅰ)含量,0.050%和0.125%SA组的血清白蛋白、高密度脂蛋白含量均显著高于对照组(P<0.05)。3)与对照组相比,0.200%SA能显著下调肌肉中过氧化物酶体增殖物激活受体γ(PPARγ)的mRNA表达量(P<0.05)。上述结果提示,饲粮中添加0.200%SA能够促进断奶仔猪生长,其作用可能是通过PPAR系统提高血清IGF-Ⅰ的含量而实现的。     

Gammaglobulin and selenium status in healthy neonatal dairy calves in Switzerland

Serum samples from 142 calves and their dams were analyzed for gammaglobulins (gammaG, calves) and selenium concentrations (Se, calves and dams). A questionnaire provided information about birth and colostrum management. The calves and their dams were distributed into two groups according the calves' gammaG concentration (< 10 and >= 10 g/L), Se concentrations were compared between groups. The correlation between gammaG and Se concentrations in the calves and their dams was analyzed. Risk factors for failure of passive transfer and Se deficiency were assessed based on the questionnaire. The gammaG concentration of 42.9 % of the calves was < 10 g/L (median: 10.9). Calves showed significantly higher gammaG values after optimized colostrum administration than calves with suboptimal colostrum administration (p < 0.004). The median Se concentration was 26.8 and 36.5 μg/L for the calves and dams, respectively. A high correlation was observed between the Se concentration of the dam and her calf (r = 0.72, p < 0.001). The calves' Se and gammaG concentrations were not significantly correlated. These results demonstrate that further efforts toward better information of farmers regarding colostrum management and Se supply are warranted.     

Improvements of immune status, intestinal integrity and gain performance in the early-weaned calves parenterally supplemented with L-alanyl-L-glutamine dipeptide

Glutamine (Gln) is an important substrate for the innate immune cells including lymphocytes and macrophages. In this report, the effects of alanyl-glutamine dipeptide (Ala-Gln) on the naïve immune system, intestinal integrity and gain performance of early-weaned calves were investigated. Early-weaned Chinese Holstein calves were intravenously administered different dosages of Ala-Gln. The effects of Ala-Gln administration were ascertained by evaluating the blood for naïve T lymphocyte subpopulations, the concentrations of serum IgG, serum IgA and intestinal mucosal secretory IgA (s-IgA), the intestinal integrity, as well as the gain performance. Results demonstrated that intravenous administration of Ala-Gln dipeptide (1.01 g/kg × d^?1) for 7 days had a positive effect on gain performance, intestinal integrity and the immune system. Calves administered doses of Ala-Gln displayed an improvement in gain performance and health status concurrent with increases in blood CD2⁺ and CD4⁺ lymphocytes, the ratio of CD4⁺/CD8⁺, serum IgA and IgG, intestinal mucosal s-IgA while decreasing the occurrence of diarrhea. Moreover, we found that animals given the effective dose (1.01 g/kg × d^?1) of Ala-Gln resulted in improved immune status and intestinal integrity relative to those given a lower (0.49 g/kg × d^?1) or higher dose (1.99 g/kg × d^?1) of Ala-Gln. These findings suggest that maintaining a certain concentration of plasma and/or tissue glutamine in the early stages of weaning is an effective alternative approach for improvement of growth performance in early-wean calves.     

Effect of age at feedlot entry on performance and carcass characteristics of bulls and steers

Seventy Angus x Simmental calves (BW = 166.3 +/- 4.2 kg) were used in a 3 x 2 factorial arrangement to determine the effect of age at feedlot entry and castration on growth, performance, and carcass characteristics. At 82 d of age, steers were castrated. Calves were placed in the feedlot at 111 (early-weaned), 202, or 371 (yearling) d of age. Steers were implanted with Synovex-S followed 93 d later with Revalor-S. Calves were harvested on an individual basis when fat thickness was estimated to be 1.27 cm. During the feedlot phase, yearlings gained faster (P < 0.01) than calves placed in the feedlot at 202 or 111 d of age (1.88, 1.68, and 1.62 kg/d, respectively); however, from 111 d of age until harvest, ADG was greatest for early-weaned calves, intermediate for cattle placed in the feedlot at 202 d of age, and lowest for yearlings (1.62, 1.47, and 1.21 kg/d, respectively; P < 0.01). Early-weaned calves spent the most days in the feedlot, followed by calves placed in the feedlot at 202 d of age; yearlings spent the fewest days in the feedlot (221, 190, and 163 d, respectively; P < 0.01). Total DMI when in the feedlot was similar (P = 0.22) among age groups; however, daily DMI was lowest for early-weaned calves, intermediate for calves placed in the feedlot at 202 d of age, and the highest for yearlings (7.1, 8.1, 10.5 kg/ d, respectively; P < 0.01). Early-weaned calves were the most efficient, followed by calves placed in the feedlot at 202 d of age; yearlings were the least efficient (227, 207, 180 g gain/kg feed, respectively; P < 0.01). Weight at harvest (682, 582, 517 kg, respectively; P < 0.01) and hot carcass weight (413, 358, 314 kg, respectively; P < 0.01) were greatest for yearlings, intermediate for cattle placed in the feedlot at 202 d of age, and lowest for early-weaned calves. Early-weaned calves had the smallest longissimus area, followed by calves placed in the feed-lot at 202 d of age; yearlings had the largest longissimus area (77, 86, 88 cm2, respectively; P < 0.01). Calves placed in the feedlot at 111 and 202 d of age had lower yield grades (3.2, 3.1, 3.5, respectively; P < 0.04), and produced fewer select carcasses than yearlings (25, 13, 48%, respectively; P < 0.01). Bulls and implanted steers both had an ADG of 1.7 kg/d when in the feedlot; however, bulls had a greater (P < 0.09) hot carcass weight (370 vs 354 kg) and a larger (P < 0.01) longissimus area (85.8 vs 81.3 cm2) than steers. Earlier feedlot placement resulted in greater quality grades but lower carcass weights.     

营养条件对荷斯坦公犊生长发育及血液中激素水平的影响

选择同期出生的48头中国荷斯坦公犊,在其1月龄时随机分为4组,Ⅰ、Ⅱ、Ⅲ、Ⅳ组分别采用全乳、全乳+精料、代乳粉(料)和精料(对照组)进行饲养,研究不同日粮饲喂犊牛对其生长发育的影响。结果表明:Ⅰ组的体重在2～6月龄时均显著高于Ⅲ、Ⅳ组(P<0.05);尽管Ⅲ组的体重和日增重在2月龄时显著低于另3组(P<0.05),但到6月龄时,其日增重达到1.35kg/d,且与Ⅰ组无显著差异(P>0.05)并明显高于Ⅳ组(P<0.05)。说明代乳料饲喂的犊牛在后期的生长能够接近全乳饲喂的水平。4组间体长指数和髋胸指数在分组饲养后的开始几个月里存在显著性差异(P<0.05)。体重、日增重以及多数体尺指标均与T3和GH浓度呈显著(P<0.05)或极显著(P<0.01)相关,T4和INS浓度仅与体斜长、体长指数和髋胸指数呈显著(P<0.05)相关,且日增重仅与T3浓度有极显著相关(P<0.01)。Ⅰ组犊牛的血清中T3浓度在2～6月龄时均显著高于Ⅳ组(P<0.05),且除6月龄以外,其余各月龄时均显著高于Ⅲ组(P<0.05)。说明血清中T3浓度可能是能反映并监控荷斯坦犊牛生长发育和营养情况的重要指标。     

Effect of early weaning on the performance of three-year-old,first-calf beef heifers and calves reared in the subtropics

The objective of this study was to investigate the effectiveness of early weaning fall-born calves on heifer and calf performance in Florida. Over two consecutive years, 3-yr-old Braford and Brahman x Angus first-calf heifers were assigned randomly to one of two treatments; early-weaned (EW, n = 20 and 30 for yr 1 and 2, respectively) and normal-weaned (NW, n = 20 and 38 for yr 1 and 2, respectively). Calves were EW on January 23 and 3 for yr 1 and 2, respectively. Following EW, all first-calf heifers were returned to bahiagrass (Paspalum notatum) pastures with the mature cowherd. Early-weaned calves were maintained on annual ryegrass (Lolium multiflorum) pastures at 8.2 and 10.7 calves/ha for yr 1 and 2, respectively, and were provided supplemental grain mixture (14% CP) at 1.0% of BW daily. Normal-weaned calves remained with their dams in the mature cowherd on bahiagrass. Final calf BW was collected on April 17 (d 84) and April 24 (d 111) for yr 1 and 2, respectively. Early-weaned calves had a greater (P < 0.001) ADG (0.17 kg/d) in yr 1, but a lower (P < 0.001) ADG (-0.24 kg/d) in yr 2 compared with NW calves. Early weaning resulted in heavier first-calf heifers with greater BCS at the time of normal weaning (August 1; 491 vs. 452 kg, with BCS = 6.34 vs. 4.75 for EW and NW heifers, respectively; SEM = 5.0 and 0.07). Heifers with EW calves had a higher (P < 0.07) pregnancy rate during both years than normal-weaned heifers (89.5 vs. 50.0 and 96.7 vs. 80.0% pregnant during yr 1 and 2, respectively). Early-weaned, first-calf heifers also had a lower (P < 0.05) calving interval in yr 2 (384 vs. 404 d; SEM = 6.0). These data suggest that EW will improve body condition of first-calf heifers resulting in an increased pregnancy rate. Early-weaned calves maintained on winter ryegrass provide producers with the ability to optimize early-weaned calf performance, while capitalizing on low cost of gain and favorable spring markets.     

谷氨酰胺对犊牛骨骼肌和小肠黏膜蛋白质及其DNA和RNA含量的影响

选用体重和出生日期相近的12头中国荷斯坦犊牛,随机分为4组,(40±1)d一次性断奶。采用胃肠外营养(total parenteral nutrition,TPN)颈静脉灌注丙氨酰谷氨酰胺(Ala-Gln)二肽的方式,研究了不同水平Gln对早期断奶犊牛骨骼肌、小肠黏膜蛋白质、DNA和RNA含量的影响。结果表明,颈静脉灌注中等水平的Ala-Gln(每千克体重0.68g/d),连续灌注7d,可以有效提高早期断奶犊牛骨骼肌蛋白质水平,且空肠黏膜DNA含量以及骨骼肌和空肠黏膜RNA含量均显著增高。     

Early-weaning and postweaning nutritional management affect feedlot performance, carcass merit, and the relationship of 12th-rib fat, marbling score, and feed efficiency among Angus and Wagyu heifers

Twelve 3/4 Angus (Angus) and 12 Wagyu-cross (1/2 Wagyu x 1/2 Angus) (Wagyu) heifers were weaned at 180 d of age and grazed on endophyte-infected tall fescue for 16 mo before entering the feedlot as 2-yr-olds. Twelve 3/4 Angus heifer calves and 12 Wagyu-cross heifer calves from the following year's calf crop were weaned at 142 +/- 4.1 d of age, immediately adjusted to an 80% concentrate diet, and finished as calves. All heifers were fed a common finishing diet until an estimated 50% of their respective group would grade USDA low Prime or better based on ultrasound predictions. Ultrasound measurements of s.c. and i.m. fat depots were recorded at 60-d intervals throughout the finishing period. Heifers finished as calves had higher (P = 0.02) marbling scores at any given fat thickness and gained more efficiently (P < or = 0.01) at any given marbling score than heifers finished as 2-yr-olds. Gain:feed decreased quadratically (P < or = 0.05) as 12th-rib fat thickness increased for Angus and Wagyu heifers. Gain:feed decreased linearly (P < or = 0.01) for Wagyu calves and quadratically (P < or = 0.01) for Angus calves as 12th-rib fat thickness increased. However, these differences in slope were not different (P = 0.34) as a result of breed among heifers finished as calves. Marbling score increased linearly (P < or = 0.01) as 12th-rib fat thickness increased for Angus and Wagyu heifers finished as 2-yrolds or as calves. However, Wagyu heifers, regardless of age at feedlot entry, had a higher marbling score (P < or = 0.05) at any given 12th-rib fat thickness than Angus heifers. Finishing early-weaned heifers as calves as opposed to 2-yr-olds results in i.m. fat deposition during a period of more efficient growth. Additionally, including Wagyu genetics into the breeding of early-weaned heifers finished as calves or as 2-yr-olds results in higher marbling scores at any 12th-rib fat thickness.     

Iatrogenic hypocalcaemia during parenteral fluid therapy of diarrhoeic calves

Acid-base balance and electrolyte concentrations, including ionised calcium, were monitored during intravenous fluid therapy of 11 collapsed diarrhoeic suckler calves aged five to 10 days. Six healthy calves of similar age and type were used to provide control data. All the diarrhoeic calves were severely acidotic (TCO2<12 mmol/litre). Isotonic sodium bicarbonate (1-3 per cent) was administered until the metabolic acidosis was half corrected, as indicated by the TCO2 increasing to 17 to 24 mmol/litre when the infusion was changed to an extracellular volume replacement fluid containing 144 mmol/litre Na+, 35 mmol/litre HCO3-, 4 mmol/litre K+ and 113 mmol/litre Cl- which was administered until the calf was discharged. Milk feeding was started as soon as the calf had a suck reflex. The treatment was successful in 10 calves. At admission the diarrhoeic calves were hypocalcaemic compared with the control calves, but their ionised calcium was significantly higher, with significantly less calcium being protein bound. Treatment with isotonic sodium bicarbonate resulted in a significant improvement in acid-base balance, but both total and ionised calcium decreased significantly, the decrease in ionised calcium being proportionately greater owing partly to a significant increase in the protein binding of calcium. The mean total, bound and ionised calcium concentrations were all significantly lower in the treated calves after they had received isotonic sodium bicarbonate than in the control calves. Further treatment with replacement fluid had no significant effect on any of the parameters apart from pCO2 which increased significantly. Milk feeding had no significant effect on plasma calcium concentrations. The calves' mean ionised calcium concentration was significantly lower at the end of the treatment than before it, but there was no difference in the mean total and bound calcium concentrations. The calves' mean plasma potassium and magnesium concentrations decreased significantly during the course of the treatment.     

Transfer of immunoglobulins and survival of newborn calves

The survival of 405 newborn calves in a large Central Florida dairy was monitored for a period of 20 weeks. Post-colostral serum samples were obtained from 234 newborn calves 2 to 7 days postpartum and assayed for total serum protein concentration using a refractometer. In the dams, the concentration of colostral immunoglobulins (Ig) at the first postpartum milking was determined by a colostrometer. Season of calving, sex, and breed of the newborn calves were recorded. The likelihood a calf would have satisfactory serum protein (greater than or equal to 5.5 g/dl) given its breed, season of calving, dam's colostral Ig, and dam's calving body condition score were determined using logistic regression analysis. Factors affecting the survival of these calves, up to 20 weeks of age, were studied using the Cox's proportional hazard model. Newborn calves' serum proteins ranged from 3.0 to 8.3 g/dl with a mean of 5.1 g/dl. Calves born to dams with satisfactory colostral Ig (greater than or equal to 50 mg/ml) were unlikely to have satisfactory serum proteins (odds ratio = 0.4) after adjustment for season of calving, parity, breed and dam's body condition score. Calves born from October to January were 3 times more likely to have satisfactory serum proteins compared to calves born during the period of February to July. However, there was no difference in serum proteins between calves born in August and September compared to the ones born in February to July. The survival rate of calves born to dams with satisfactory levels of colostral Ig was poor compared to ones born to dams with low colostral Ig.     

Nutrient digestibility, faecal physicochemical characteristics and bacterial glycolytic activity of growing pigs fed a diet supplemented with oligofructose or trans-galactooligosaccharides

The effect of oligofructose (FOS) or trans-galactooligosaccharides (TOS) inclusion at 10 g/kg diet for growing pigs, at the expense of cornstarch (CON), on growth performance, nutrient digestibilities, and faecal physicochemical parameters was determined. In addition, concentration of volatile fatty acids (VFA) and bacterial -glucosidase, β-glucosidase, β-galactosidase and β-glucuronidase activities in faeces were determined as markers of intestinal microflora metabolic activity. Twelve 35-day-old castrated pigs were allocated to CON, FOS and TOS dietary treatments for an experimental period of 4 weeks. Dietary treatments did not affect animal growth performance. FOS and TOS pigs tended to have a lower faecal output than CON pigs by approximately 6.0% and 1.7% respectively. FOS and TOS did not affect total tract apparent digestibility of dry matter, organic matter, fat, crude protein, crude fiber, ADF and cellulose. Digestibility of carbohydrate components such as nitrogen free extract and NDF was significantly (P ≤ 0.05) higher in TOS pigs compared to CON and FOS. Digestibility of hemicellulose in TOS pigs did not differ from FOS but was significantly higher from CON. The experimental period had a significant effect on most of the parameters determined. There were no significant (P ≤ 0.05) differences between treatments regarding total VFA concentration and faecal bacterial enzyme activities. Nevertheless, an increased saccharolytic activity in the gut of FOS and TOS pigs could be postulated by the trends for apparently higher VFA concentration and bacterial -glucosidase and β-galactosidase activities.