Factors associated with intersucking in Swiss dairy heifers

Intersucking is a problem that may lead to udder damage, mastitis, milk loss, and culling of breeding animals. To analyse the risk factors for intersucking in dairy heifers in Switzerland, we asked 130 randomly selected dairy farmers about a broad spectrum of environmental factors that might be associated with intersucking (such as housing conditions, management, and the feeding of calves and heifers). In total, 2768 heifers (Swiss Brown Cattle, Simmental and Holstein Friesian) were included of which 303 had ever performed intersucking. Data at the farm level were analysed using path analysis (linear and logistic regression). Two outcome variables were considered: the occurrence of intersucking on the farm and the proportion of intersucking heifers above the cut-off of 7.2%. Farms where calves had no access to barnyard or pasture, where calves were reared in pens in enclosed buildings, where heifers after weaning were not restrained while feeding, where heifers after weaning received <0.5 kg concentrate per day, and where heifers after weaning were fed ≥40% maize silage (dry-matter ratio) were most likely to have intersucking heifers.     

Beef heifer production as affected by indoor feed intensity and slaughter age when grazing semi-natural grasslands in summer

Only limited knowledge exists on how to produce high-quality beef carcasses when the cattle also are grazing semi-natural grasslands for nature conservation purposes. The objectives of the two factorially-designed trials were to determine the effects of indoor feed intensity (low vs. high) and slaughter age (18 vs. 22 months) on performance and carcass quality of beef heifers, raised from weaning until slaughter and grazing semi-natural grasslands during growing seasons. In the first trial, 56 Charolais heifers were used of which 28 were fed only grass-clover silage ad libitum (low; CL), and another 28 heifers were fed 2.0 kg of grain daily in addition to the silage (high; CH). In the second trial, 28 Angus heifers were fed grass-clover silage at 80% ad libitum (low; AL), whereas another 28 heifers were fed silage ad libitum (high; AH). According to a national nature conservation score, the grazing pressure on the semi-natural grassland was classified as having been satisfactory to maintain the floristic diversity as no litter had been accumulated onto the sward. From weaning until slaughter, no difference in average daily gains (ADG) was found between the CH and the CL, whereas the AH had higher ADG than the AL (693 vs. 573 g, P < 0.001). Heifers in both trials had higher carcass weights and more fat, Charolais heifers also had better conformation and Angus heifers had higher dressing percentage at 22 months than at 18 months of slaughter age (P < 0.05). In conclusion, carcass traits in both trials were more affected by slaughter age than by feed intensity and desirable grazing effects were achieved on the pasture.     

Buffalo heifers selected for lower residual feed intake have lower feed intake,better dietary nitrogen utilisation and reduced enteric methane production

This study was conducted to evaluate the utilisation of the residual feed intake (RFI ) as a feed efficiency selection tool and its relationship with methane emissions. Eighteen Murrah buffalo (Bubalus bubalis ) heifers were fed ad libitum with total mixed ration (TMR ) for 120 days. Based on linear regression models involving dry matter intake (DMI ), average daily gain (ADG ) and mid‐test metabolic body size (MBW ^0.75), heifers were assigned into low and high RFI groups. The RFI varied from ?0.09 to +0.12 kg DM /day with average RFI of ?0.05 and 0.05 kg DM /day in low and high RFI heifers respectively. Low RFI heifers ate 11.6% less DM each day, yet average daily gain (ADG ) and feed utilisation were comparable among low and high RFI groups. Low RFI heifers required significantly (p  < .05) less metabolizable energy for maintenance (ME m) compared to high RFI heifers. Apparent nutrient digestibility showed non‐significant difference (p >  .05) among low and high RFI groups. Although the nitrogen balance was similar among heifers of low and high RFI groups, nitrogen metabolism was significantly higher (p  > .05) in high RFI heifers. Comparison of data from heifers exhibiting the low (n  = 9) and high (n  = 9) RFI showed that the low RFI heifers have lower enteric methane production and methane losses than high RFI heifers. In conclusion, results of this study revealed that selection of more efficient buffalo heifers has multiple benefits, such as decreased feed intake and less emission of methane.     

西门塔尔母牛的育成期选优提纯

西门塔尔母牛育成期的生长发育规律主要表现为体重的增加和体型的变化,在整个发育过程中体现出本身系统发育的阶段性和个体发育的不平衡性。育成母牛１８月龄时日增重达８８１ｇ,体重达４３４．６ｋｇ,占成年母牛体重的７８．９％;体长率达１２２．０％,占成年母牛体长率的９５．３％。     

氨基酸缺乏对母犊牛生长和日粮养分消化代谢的影响

研究赖氨酸（Lys）、蛋氨酸（Met）和苏氨酸（Thr）缺乏对3-6月龄中国荷斯坦母犊牛生长和日粮养分消化代谢的影响,为生产中判断母犊牛氨基酸缺乏症提供依据,并对后续母犊牛氨基酸需要量的确定提供理论依据。【方法】 72头84日龄中国荷斯坦母犊牛,按体重和出生时间相近原则随机分为4个处理组,限量饲喂4种不同氨基酸模式的饲粮,分别为氨基酸平衡组（PC组）、赖氨酸扣除组（PC-Lys）、蛋氨酸扣除组（PC-Met）和苏氨酸扣除组（PC-Thr）,氨基酸扣除量均为PC组的30%。试验期97d,其中预饲期7d,正试期90d。于正试期第1、30、60、90天测定犊牛体重、体尺和乳头长度;在132—138和173—179日龄每组分别选取6头健康犊牛进行2期消化代谢试验,收集粪、尿和饲料样品,测定营养物质表观消化率及氮代谢;正试期每天记录采食量。【结果】与饲喂氨基酸平衡饲粮的犊牛相比：（1）扣除Lys显著降低90—180日龄犊牛饲料转化效率（P＜0.05）,日增重（ADG）为各组最低（P＞0.05）;扣除Met和Thr对90—180日龄犊牛ADG和饲料转化效率没有显著影响（P＞0.05）;（2）扣除Lys或Thr显著降低犊牛粪便评分（P＜0.05）,但对腹泻率没有影响（P＞0.05）,以PC-Lys组腹泻率最高;3）扣除Lys、Met或Thr均不影响犊牛体尺（P＞0.05）,但扣除Lys后犊牛乳头长度增长率均低于PC组（P＞0.05）;4）扣除Lys、Met或Thr不影响日粮养分表观消化率（P＞0.05）,但扣除Lys显著降低173—179日龄犊牛氮利用率和氮生物学价值（P＜0.05）。【结论】在本试验设定的氨基酸平衡饲粮基础上,扣除Lys对犊牛生长发育和氮代谢有不利影响,扣除Thr影响犊牛腹泻,扣除Met对犊牛无明显影响。     

微生物制剂在幼龄反刍动物营养与饲料中的应用

微生态制剂作为一种活性物质被用于动物营养与饲料中,具有巨大的发展前景.反刍动物出生后要经历营养、环境和心理三大方面的应激,从非反刍到反刍行为的发生是动物一生中最重要的生长发育生理时期,将微生物制剂导入幼畜培育体系中,可让益生菌及早在消化系统中发挥作用.本文将结合本团队近年来微生物制剂在犊牛阶段中的研究结果作一综述.     

荷斯坦青年牛初次配种妊娠月龄对头胎和二胎产奶量和繁殖性能的影响

旨在研究母牛初次配种妊娠月龄（age at first pregnancy,AFP）对其泌乳性能和主要繁殖性能的影响。本研究以我国北方地区2个规模化奶牛场13 927头荷斯坦母牛（A牧场8 091头,B牧场5 836头）的生产数据为基础,统计了母牛AFP、头胎和二胎的产奶量、产后首次发情时间、首次配种时间和首次受孕时间,然后将母牛根据AFP的早晚（12~19月龄）分为8组,对各试验组母牛的头胎和二胎产奶量和主要繁殖性能的数据进行比较分析。结果表明：1）2个规模化奶牛场荷斯坦青年牛AFP以13和14月龄为主（总占比70.1%）;2）AFP可显著影响荷斯坦青年牛头胎和二胎的305 d产奶量（P<0.05）,其中AFP为14月龄时A牧场头胎和二胎305 d产奶量均最高,分别为15 102和15 534 kg;3）AFP可显著影响荷斯坦青年牛头胎和二胎产后首次发情时间和受孕时间（P<0.05）,AFP为14月龄时头胎产后首次发情和受孕情况最优;4）对于产后首配时间,除A牧场头胎AFP为16月龄时产后首次配种时间显著高于AFP为17月龄时（P<0.05）外,其余各组间均无显著性差异（P ≥ 0.05）,并且各组间配种时间相差≤ 5 d;5）通过对A牧场在场牛（2 703头）与淘汰牛（660头）的AFP记录数据分析发现,在场牛的AFP为14.52月龄,显著高于淘汰牛的AFP（P<0.05）。因此,在北方地区现有的生产管理水平下,14月龄可能是荷斯坦青年牛最适宜的初次配种妊娠月龄,这对我国规模化奶牛场选择荷斯坦青年牛适宜的初次配种月龄具有一定参考价值。     

Mineral composition and microstructure of the abaxial hoof wall in dairy heifers after biotin supplementation

The aim of this study was to evaluate the effect of daily biotin supplementation on the mineral composition and microstructure of the abaxial hoof wall in dairy heifers. The heifers were housed on a concrete floor and fed for weight gain more than 800 g per day, which is a challenging environment for the hoof. Twelve crossbred dairy heifers (Jersey × Holstein) were divided into two treatment groups. Animals in the control group (n = 6) received a diet without supplemental biotin, while the heifers in the biotin-supplemented feed group (n = 6) each received 20 mg of biotin daily for 120 days. Samples of the abaxial hoof wall were collected from the outer claw of the fore and hind limb, before and after supplementation. The samples were evaluated by X-ray fluorescence spectrometry, computed microtomography, atomic force microscopy and confocal laser scanning microscopy. Biotin supplementation increased the sulphur content and decreased the calcium and potassium content in the abaxial hoof wall. Biotin treatment also increased the percentage of horn tubules with smaller diameter marrow (17–51 µm). However, biotin did not influence the surface relief of the hoof wall, suggesting that its action is limited to the inner layers of the stratum corneum. Daily supplementation with 20 mg of biotin promoted changes in the mineral composition and microstructure of abaxial hoof wall of crossbred dairy heifers. These findings suggest biotin supplementation improves hoof quality and may help to understand the function of biotin in the stratum corneum.     

Cumulative Forage Production, Forage Quality and Livestock Performance from an Annual Ryegrass and Cereal Rye Mixture in a Pine Walnut Silvopasture

Annual ryegrass (Lolium multiflorum Lam.) and cereal rye (Secale cereale L.) pastures can extend the grazing season in the lower Midwest. There is little data from this region on the productivity of these forages in a silvopasture system. Our objective was to determine the forage and livestock production from annual ryegrass/cereal rye in a silvopasture versus an open (non-forested) system. This study was conducted near New Franklin, MO, USA. The treatments were (1) annual ryegrass/cereal rye planted into a 6- to 7-year-old stand of pitch pine (Pinus rigida Mill.) × loblolly pine (Pinus taeda L.) hybrids and black walnut (Juglans nigra L.) (TREE treatment) and (2) the same forages planted into pastures without trees (OPEN treatment). Marshall annual ryegrass and cereal rye were no-till seeded at 22 and 67 kg ha^-1 of pure live seed, respectively, on 18 September 2000 and 30 August 2001. Treatments were replicated three times in a randomized complete block. In March 2001 and 2002, three beef heifers were assigned to each pasture and rotationally grazed until early June. Cumulative forage production and quality were measured for each treatment. Cumulative forage production in the TREE treatment was reduced by approximately 20% compared to the OPEN treatment. However, beef heifer average daily gain and gain ha^-1 were equal for both treatments. Beef producers using a annual ryegrass/cereal rye in a silvopasture system likely would not sacrifice livestock production when hybrid pine and black walnut trees are 6- to 7-year-old when compared to an open pasture. Contribution of the Missouri Agricultural Experiment Station and the University of Missouri Center for Agroforestry. This work was funded through the University of Missouri Center for Agroforestry under cooperative agreements AG-02100251 with the ARS and CR 826704-01-0 with the US EPA. The results presented are the sole responsibility of the authors and/or the University of Missouri and may not represent the policies or positions of the ARS or EPA.     

应用体尺指标估测西杂后备母牛体重

通过测定张掖市甘州区甘浚镇120头西门塔尔杂交后备母牛的体高、胸围、体斜长和实际体重，发现后备母牛生长符合母牛育成期的生长规律，可以用公式来估测后备母牛的体重，用约翰逊公式和体重估测系数估测体重误差率均在5％以下。