饲喂预混料对奶牛产奶量的影响

奶牛是目前畜牧生产中转化效率最高的动物，每天从奶中分泌出大量矿物质和维生素，奶牛饲料矿物质和维生素的平衡，直接影响着奶牛的身体健康与生产性能。奶牛预混料也同猪鸡预a混料一样，在奶牛生产中具有不可替代的作用。但由于种种原因，奶牛预混料在我国一直没有得到很好的利用，使得这一能给奶牛生产者带来巨大经济效益的技术没有发挥其应有的作用，这对于从事奶牛生产的用户来说是一种巨大的损失。近两年来，随着我国市场经济的发展，牛奶及奶制品的市场需求不断扩大，奶源渐显紧张，原料奶价格不断上升，奶牛生产的经济效益也不断提…     

牛得喜对奶牛生产性能的影响

实验研究了奶牛日粮中添加牛得喜(SCCNCMl077)对奶牛生产性能的的影响。实验选用了50头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为试验组和对照组。试验结果表明,试验组平均产奶量比对照组提高了1.52kg,差异显著(P<0.05),而试验组乳脂率、乳蛋白率分别下降了0.09%、0.07%,但均差异不显著(P>0.05)。     

日粮中添加碳酸氢钠对奶牛生产性能的影响

通过对奶牛添加碳酸氢钠的研究结果表明：按混合精料量的1.5%添加，对高精料型日粮的泌乳牛可增加其瘤胃中挥发性脂肪酸的含量，并使产奶量提高3.13%，乳脂率增高0.07%,从而增加乳牛业的经济效益。同时，试验测定了西昌市区黑白花奶牛瘤胃挥发性脂肪酸的含量及其组成百分率，为今后研究奶牛的消化生理提供依据。     

羟基蛋氨酸钙对奶牛生产性能影响的研究

将羟基蛋氨酸钙添加到奶牛日粮中进行饲养试验。结果表明，试验期末，两试验组奶牛产奶量与对照组相比分别提高3．80％和4．79％，但未达显著水平；乳脂率分别提高3．12％和4．50％；奶料比、乳蛋白含量与对照组相比无变化。     

复合预混料提高奶牛产奶量的试验

本试验在基础日粮中添加占精料量1%的复合预混料,经35天的试验,结果表明:试验组牛平均每头每天比对照组多产奶2.1kg,产奶量提高14.6%,差异极显著(P<0.01),试验组牛头均每天增收3.07元,经济效益显著。     

稀土添加剂对泌乳奶牛生产性能的影响

在基础日粮中添加稀土添加剂，观察对400kg体重的泌乳奶牛生产性能的影响。结果表明：在基础日粮中添加20mg／kg体重稀土添加剂的I组作用效果明显优于添加12．5mg／kg体重的Ⅱ组。试验I组、Ⅱ组的日均产乳量、乳脂肪、乳比重分别比对照组提高9.57％、9．87％、0．195％；7．59％、3．18％、0．097％；且组间存在极显著差异(P＜0．01)。     

新型奶牛预混料对热应激下的奶牛生产性能的影响

试验结果表明新型奶牛预混料能显著减缓热应激下奶牛产量的下降(p<0.05),试验组比对照组平均增加产奶量1.5kg/头、日,能显著降低乳中的体细胞数(p<0.05),改善奶牛的机体健康。     

影响奶牛乳脂率的因素及提高措施

乳脂率是衡量奶牛生产性能的一项重要指标，由于许多地区已经实行“以质论价”的原则，所以乳脂率对于奶牛饲养经济效益的高低具有重要意义。本文就影响奶牛乳脂率的因素和提高奶牛乳脂率的措施作一综述。     

大唐C347奶牛预混料对奶牛生产性能的影响试验

随着改革开放,经济建设持续发展,我国人民生活水平不断提高,人们要求肖费较多的动物性食品,而牛奶是饲料转化率最高,营养结构合理的优质蛋白质,也是钙和B族维生素的丰富来源之一.因而,牛奶备受人们喜爱.     

稀土添加剂对泌乳奶牛生产性能的影响

稀土是镧系及钇、钪等17种元素的总称。稀土作为一种新型饲料添加剂,具有用量少、促生长效果明显、在畜产品中残留低、安全可靠。现应用于畜禽养殖的稀土添加剂有4种:硝酸稀土、盐酸稀土、维生素C-稀土和碳酸稀土。张建文(1991)报道,添加200毫克/千克和800毫克/千克硝酸稀土时,试验组较基础日粮组的产奶量分别提高9.23%和21.52%。1稀土添加剂可提高奶牛产奶量及乳脂率日粮中稀土添加量在12.5～20毫克/千克体重范围时,以20毫克/千克体重添加量的效果为佳,且随稀土添加量的增加,乳牛的产奶量有提高的趋势,这个结果与张建文(1991年)的报道结果…     

饲料形状和质量对火鸡生产性能的影响

Aviagen Turkeys 公司(以下简称“ATL”)提供了获得不同火鸡品种目标性能所需的营养规范指南,然而为了使火鸡对饲料营养密度做出积极反应,它们需要定期消耗所需的饲料量来达到这一目标。     

精料不同补饲量对肉山羊增重的影响

选择体重基本一致、60日龄左右的 60只南×本杂交断奶羔羊 ,按平均体重分为 5组 ,在全舍饲条件下 ,分别饲喂精料 5 0、10 0、15 0、2 0 0和 3 0 0g/(只·d)。结果表明 :育肥山羊 3 0天平均日增重分别为 6 70、14 0 0、42 67、5 7 3 3和 68 67g ,精料转化率分别为 13 40 %、14 0 0 %、2 8 45 %、2 8 67%和 2 5 3 4%。分析表明 ,育肥山羊精料喂量为 15 0g/(只·d)时 ,其利用率最高。     

饲料的贮藏及精饲料贮藏性的改善

饲料以春秋之间生产的农作物为主,其它还包括食品加工业的残渣,特殊用饲料等可以周年生产的产品。这些饲料,当地生产当地利用的情况较少,在一定时间或一定地域大量生产的饲料,经过适当的贮藏,在饲料不足的时期提供适时适量的供应是必要的。如果饲料贮存不当,会导致品质下降或变质,引起养分的大量损失。因此,使生产的饲料经过长期贮藏得到有效利用,科学的贮藏是十分重要的。一般饲料变质的原因有:①霉菌、细菌等有害微生物的繁殖;②饲料本身存在的酶的作用;③害虫、鼠类的危害。饲料的科学贮藏就是要预防和消除这些饲料变质的原因,提高贮藏饲…     

复合酵母培养物对奶牛生产性能的影响

<正>近年来,国内外有很多关于酵母培养物在奶牛生产中应用的研究,在日粮中添加酵母培养物可以稳定瘤胃内环境,促进有益菌群的增殖(张连忠,2009),同时     

The effect of residual feed intake classification on forage intake by grazing beef cows

Although feed intake and efficiency differences in growing cattle of low and high residual feed intake (RFI) classification have been established, little is known about the difference in grazed forage intake between beef cows of known RFI classification. Two experiments were conducted using Hereford cows for which RFI had been determined as heifers using the GrowSafe 4000E feed intake system, after which heifers had been divided into thirds as low RFI, mid RFI, and high RFI. During Exp. 1, 2 replicates of low and high RFI cows (n = 7/replicate) in mid- to late-gestation were blocked to 1 of 4 non-endophyte-infected tall fescue paddocks (1.8 to 2.4 ha), which they grazed continuously for 84 d during summer. Using grazing exclosures, weekly rising plate meter readings, and forage harvests every 21 d, average forage DMI was calculated. Low and high RFI groups did not differ (P > 0.05) in BW change or BCS change over the trial (19.5 vs. 22.1 kg of BW gain and 0.11 vs. 0.10 BCS gain), but low RFI cows had a 21% numerically lower DMI than high RFI cows (12.4 vs. 15.6 kg/d; P = 0.23). The average area needed per paddock over the trial was similar for low and high RFI cows (1.71 vs. 1.82 ha; P = 0.35), and the average DM on offer over the trial was less for low RFI than for high RFI cows (4,215 vs. 4,376 kg; P = 0.06). During Exp. 2, 3 replicates of low and high RFI cows with their calves (n = 4 pair/replicate) strip-grazed stockpiled and early spring growth tall fescue paddocks (0.7 to 0.9 ha) for 60 d in late winter and early spring. Because of limiting forage availability and quality at trial initiation, cow-calf pairs were also fed 3.31 kg/pair of pelleted soyhulls daily. Pre- and post-grazed forage samples were harvested for 4 grazing periods, and forage growth was estimated using a growing degree days calculation and on-site weather station data. Performance did not differ (P > 0.05) between low and high RFI cows throughout the experiment (18.4 vs. 26.6 kg of BW gain and -0.04 vs. 0.15 BCS gain). Despite the utilization of forage offered being similar for low and high RFI cow-calf pairs (P > 0.05), low RFI cows and their calves had an 11% numerically lower DMI than high RFI pairs (12.5 vs. 14.1 kg/d; P = 0.12). We concluded that either no intake differences existed between low and high RFI cows or that current methodology and small animal numbers limited our ability to detect differences.     

The effect of energy-rich feed supplements for cows on the health of their calves]

Experiments were carried out with 24 pregnant cows and their calves. The cows were divided in 2 equal groups. One of these received a supplement of animal fat additional to the feed from 4 weeks a. p. to 6 weeks p. p. Apart from clinical examinations following laboratory investigations in the blood were performed: hematological parameters, cholesterol, lipids, free fatty acids, ketone bodies, protein, glucose, bilirubin, transaminases, alkaline phosphatase, Ca, Mg, P, K, Na, Cl. The addition of fat to the feed of cows influenced the energy metabolism of the cows, the body weight of the newborn ones and some hematological parameters (incl. protein) of the calves positively.     

Effect of strategic feed supplementation on productive and reproductive performance in yak cows

A total of 2230 yak cows (5-13 years of age) in two populations with different milking systems were investigated. One population had a system of milking once a day (MOD), and the other population twice a day (MTD). The average milk yield of MOD cows was 0.7 +/- 0.2 kg/day within a milking period of 109 +/- 9 days. This compared with an average of 1.24 +/- 0.3 kg/day in 127 +/- 6 days in MTD yaks (p < 0.01). The cows showed a calving rate of 71% under the MOD system and 51.4% under the MTD system. Three farms with a total of 104 MTD cows between six and 12 years of age were used to provide three different feeding groups. The groups were fed with, or without oat hay or highland barley straw in amounts of 1-1.5 kg/head/day from December to April. The three farms were designated as Farm I, Farm II, and Farm III. Farm I had 41 cows with body weight of 230 +/- 67 kg each for grazing with no supplement (GNS). Farm II had 30 animals with body weight of 216 +/- 28 kg each for grazing + oat hay (GOH). Farm III had 33 animals body weight of 221 +/- 34 kg each for grazing + highland barely straw (GBS). The calving rates of the cows in GOH and GBS were 23 and 19% higher, respectively, than GNS cows (p < 0.01), and the highest rate reached 76.7% in GOH. The live weight loss of the cows in GNS was considerably higher (p < 0.01) than in the two other groups. Ten GOH cows and 12 GNS cows were used to collect milk samples for measuring the progesterone concentration using RIA kits provided by IAEA/FAO: Milk was sampled every five days from calving until 90 days postpartum. In the unsupplemented group, milk progesterone (P4) levels suggested that cows had started cyclic ovarian activity by 40 days postpartum, whereas only 25% had been observed in estrus. In the supplemented group, 80% of cows had started cyclic ovarian activity by the same time and 70% had been seen in estrus. Two types of cyclic activity in terms of progesterone changed were found. With Type I (normal), 50 and 80% of cows from GNS and GOH, respectively, had cyclic changes of P4 in milk at 40 days postpartum. With Type II, the P4 levels in the milk remained 0.89 ng/ml until 90 days postpartum. A total of 46 grazing cows between five and 13 years of age (body weight 214 +/- 68 kg) was used to collect blood samples to measure concentrations of nutrient of metabolites at two weeks pre-calving and at two weeks, two months and four months postcalving, respectively. The concentrations of nutrient metabolites [albumin, globulin, urea, beta-hydroxybutyrate (BHB) and inorganic phosphorus] suggested general underfeeding of energy and protein in the winter/late pregnancy period with some recovery in lactation. Energy constraints appeared again as the summer progressed. No dietary phosphate deficiency was found. BHB and albumin testing on serum yaks could be a useful tool to identify poor nutritional status during the winter and so illustrate the need for supplementation.     

热应激对奶牛生产性能的影响及预防措施

1　热应激对奶牛生产性能的影响1 1　对奶牛采食量的影响　外界环境温度升高引起的热应激往往导致奶牛采食量下降。奶牛从2 2～ 2 5℃时采食量开始下降 ,30℃以上时急剧下降 ,40℃以上时不耐热的品种将停止采食。高温环境中奶牛采食量下降的程度因品种和饲料组成的差异而略显不同 ,但总的下降趋势基本一致。热应激导致奶牛采食量下降的机制为 :1 )奶牛在热应激时 ,体内三碘甲腺原氨酸T3、甲状腺素T4分泌量大幅度下降 ,影响胃肠蠕动 ,延长食糜过胃时间 ,使胃充盈 ,通过胃壁上的胃伸张感受器作用于下丘脑厌食中枢 ,反馈性地减少采食量 ;2 )…     

The effect of feed barrier design on displacements during feeding of dairy cows in small herds

The aim of this study was to investigate the effect of feed barrier design on displacements in dairy cows fed only roughage diets in the bunk in small commercial dairy herds. Six Norwegian dairy herds with open barriers (OB) and six herds with individual headspace barriers (IHB) were randomly selected. Number of displacements and withdrawals without physical contact was somewhat higher, but not significantly higher, in the IHB herds than in the OB herds but the variation between herds within the type of barrier were very large. The number of pushes and buttings directed towards the front part of the body of cows was significantly higher in the OB herds than in the IHB herds whereas pushes and butts directed towards the side of cows were significantly higher in the IHB herds than in the OB herds.     

Effect of twinning on the feed intake, performance and health of dairy cows

The aim of this study was to assess the effect of bearing twins on the health and performance of dairy cows. Data from twin-bearing Holstein Friesian cows at the Langhill Dairy Research Centre between January 1990 and July 2002 were compared to single-bearing cows to determine if there was any significant difference in milk production, feed intakes, health and fertility. There were 122 twin births (from 104 different cows) in the Langhill herd, a rate of 4.7% during the study period.

The incidence of twinning was higher in high genetic merit cows (select genetic line cows) and increased with parity (r = 0.870, P < 0.01). Compared to a single-bearing cow, a twin pregnancy was associated with a shorter gestation period, an increased chance of a retained placenta after calving and a poorer body condition score post-calving. The post-calving condition score of twin-bearing cows was negatively correlated with the total weight of calves born (r = − 0.235, P < 0.05). Twin-calving cows also had significantly more dystocia, a higher chance of having a dead calf, an increased number of days from calving to their first observed heat and number of days from calving to their first service. Dystocia was positively correlated with the number of dead calves at birth (r = 0.309, P < 0.01) and with the total weight of calves born (r = 0.211, P < 0.05). Twin-bearing cows on a low-concentrate diet had an increased chance of having metritis and/or endometritis compared to single-bearing cows on the same diet. There was no significant difference in the reason for culling or the time at which cows were culled post-calving, however, twin-bearing cows on a low-concentrate diet were 3.2 times more likely to be culled than a single-bearing cow, with cows on a high-concentrate diet having equally high levels of culling. There were no significant differences between twin- and single-producing cows' mean daily feed intakes, daily milk yields, total milk yields and milk fat and protein compositions during early, mid and late lactation pre and postpartum on a low- or high-concentrate diet. The body condition and drying off period of twin pregnant cows should be managed to avoid post-calving health and performance problems.