肉牛肥育的两种方法

肉牛肥育是科学应用饲料和管理技术,以尽可能少的饲料消耗获得尽可能高的日增重,提高出栏率,生产出大量优质牛肉。随着各地养牛业的发展,肉牛养殖小区及规模育肥场数量不断增加,养殖户对肉牛肥育技术越来越关注,下面介绍肉牛肥育的两种方法——持续肥育法和后期集中肥育法。     

不同饲养方式对肉牛肥育效果的比较

饲料是发展畜牧业的基础.达到营养水平和满足需要是生产优质肉牛的关键.在贵州石阡传统的肉牛饲养方式下,饲料饲草营养水平不足,牛的肥育用时较长,效果较差,生产的牛肉品质也受到影响.肉牛短期肥育就是将具有一定体况,身体不丰满的架子牛或犊牛集中补饲3～4个月,使其快速丰满,长膘出栏.但在石阡具体的自然资源的制约下,完全舍饲代价太高,农民也很难接受.为彻底了解不同饲养方式对肉牛肥育效果的影响,进行本试验.     

肉牛养殖技术分析与饲喂管理方法探讨

随着我国社会经济的发展,人们的生活水平提高,对肉类的消费要求也越来越高,尤其是优质牛肉的需求量也越来越大,牛肉价格的居高不下激发了大量养殖户对饲养肉牛的兴趣,甚至一些地区将饲养肉牛发展成地区重点.然而,人们对饲养肉牛的养殖技术及饲养管理方法的不足,所带来的经济效益严重下降,本文根据相关经验与技术,对肉牛场所的建设、肉牛营养、饲料、育肥等方面知识的介绍,希望为广大肉牛养殖户提供一定参考.     

肥育期肉牛的饲养管理技术要点

肥育期肉牛饲养管理是肉牛生产的重要阶段。随着我国畜牧业的快速发展及市场对牛肉需求量的日益增加，肉牛养殖业得到了快速发展。然而，目前我国肥育期肉牛生产各地技术差别不一，特别是有些养殖场(户)缺乏技术，致使养殖经济效益偏低。为解决肉牛养殖中的技术，提高肉牛生产水平，提高肉     

肉牛肥育的两种方法

肉牛肥育是科学应用饲料和管理技术,以尽可能少的饲料消耗获得尽可能高的日增重,提高出栏率,生产出大量优质牛肉。随着各地养牛业的发展,肉牛养殖小区及规模育肥场数量不断增加,养殖户对肉牛肥育技术越来越关注,下面介绍肉牛肥育的两种方法——持续肥育法和后期集中肥育法,希望对广大养牛的农民朋友有所帮助。1持续肥育法持续肥育法是指犊牛断奶后,立即转入肥育阶段进行肥育,一直到出栏(12～18月龄,体重400～450千克)。使用这种方法,日粮中的精料大约可占总营养物质的50%以上。持续肥育由于在饲料利用率较高的生长阶段保持较高的增重,加上饲…     

育肥肉牛的饲养管理

肥育肉牛包括幼龄牛、成年牛和老残牛，肥育的目的是科学应用饲料．以尽可能少的饲料消耗获得尽可能高的日增重，提高出栏率，生产出大量优质牛肉。肥育期肉牛的饲养管理应从以下几个方面做好工作。     

育肥肉牛的饲养管理

肥育肉牛包括幼龄牛、成年牛和老残牛.肥育的目的是科学应用饲料,以尽可能少的饲料消耗获得尽可能高的日增重,提高出栏率,生产出大量优质牛肉.肥育期肉牛的饲养管理应从以下几个方面做好工作.     

肉牛生长肥育规律及其应用

综合分析肉牛生长发育规律，肌肉生长的饲料利用率及影响肉牛肥育的主要因素，指出在肥育肉牛时，要合理利用这些规律，做到营养补充与各阶段需要相吻合，并利用饲料，饲养与动物间的正组合效应，以达到最佳的肥育效益。     

肉牛高效肥育组方

所谓肉牛高效肥育,一是指利用以牧草、秸秆、糟渣、尿素、添加剂等非粮型饲料为主肥育肉牛,这不仅符合草食家畜的生理,而且可大幅度降低饲养成本;二是指强度催肥,生产高档牛肉,提高经济效益,故称其为高效肥育.     

肥育肉牛的管理与饲养技术

肥育肉牛包括幼龄牛、成年牛和老残牛,肥育的目的是科学应用饲料和管理技术,以尽可能少的饲料消耗获得尽可能高的日增重,提高出栏率,生产出大量优质牛肉.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein