肉牛最佳三元杂交组合筛选试验

本试验用世界著名肉牛品种皮埃蒙特牛、夏洛来牛、利木辛牛和德国黄牛为父本,以适应性较强的西门塔尔牛和当地固有品种蒙古牛的杂交优秀个体母牛为母本,分别采用了“皮×西×蒙、夏×西×蒙、利×西×蒙和德×西×蒙”等三元杂交组合,并对各种杂交组合所产生的杂种牛（简称“肉杂牛”）的肉用性能进行了统计分析,结果“皮×西×蒙”杂交组合产生的肉杂牛肥育期日增重比夏×西×蒙、利×西×蒙和德×西×蒙组合分别高出0．13kg、0．17kg、和0．24kg;净肉率分别高出1．1％、0．47％和1．27％;屠宰率分别高出1．30％、0．09％和1．39％;骨肉比分别高出0．15、0．08和0．17。结果显示皮西蒙杂交组合的日增重高于其他三种组合,差异显著;而净肉率、屠宰率、肉骨比等指标也较高,但差异不显著。说明皮×西×蒙杂交组合后代增重速度快,饲养周期短,肉用指标好,可在武威市乃至周边地区推广。     

西门塔尔与利木赞肉牛杂交效果比较分析

在益阳市分别以西门塔尔、利木赞等2个肉用牛品种为父本,本地黄牛为母本开展杂交试验,确定适宜的杂交组合.随机测定了益阳市350头不同生长阶段的F1代杂交牛(西本杂292头、利本杂58头)的体重、体尺,结果表明:不同生长阶段西本杂初生重和6月龄以后各阶段体重较利本杂大;12月龄公母平均体重达244.5kg,比后者提高8％;18月龄公母平均体重为330kg,比后者提高17％多;24月龄达394kg.因此,在本地区以西门塔尔牛为父本对本地黄牛进行改良效果较好.     

西×蒙F_2代犍牛与蒙古犍牛屠宰对比试验

[目的]为探讨西门塔尔牛杂交改良蒙古牛的产肉性能及效果。[方法]对18月龄西×蒙F2代犍牛和蒙古犍牛进行屠宰对比试验。[结果]18月龄西×蒙F2代犍牛的平均活重、屠体重和净肉重分别达到511.67kg、291.21kg和233.51kg,较同月龄蒙古犍牛高出131.67kg、80.28kg和64.32kg;提高了34.65%、38.06%、和38.01%;差异均极显著(P0.01);18月龄西×蒙F2代犍牛的平均屠宰率和净肉率分别提高了1.40%和1.12%,差异显著(P0.05)。[结论]利用西门塔尔牛杂交改良蒙古牛效果显著,可以明显提高蒙古牛产肉性能。     

南德文牛改良雷州黄牛的效果分析

利用湛江种公牛站提供的南德文种公牛冷冻精液对本地雷州黄牛进行人工授精。现已配母牛 5万头 ,产杂交牛 2万多头。杂交牛平均初生体重 2 5kg,1岁体重可达 30 0kg,1 8月龄体重达 477kg ,分别比本地雷州黄牛提高 78 57% ,87 5 %和 87 1 % ,杂交优势明显。且杂交个体呈现较好的肉用体型 ,产肉性能显著提高 ,屠宰率和净肉率分别为 60 1 %和 49 58%。     

肉牛改良蒙古牛效果分析

上世纪70年代以来锡林郭勒盟先后引进安格斯、利木赞、夏洛来、西门塔尔等肉牛品种改良蒙古牛.分析测定了不同品种杂交一代公母牛及蒙古牛6月龄、18月龄和30月龄体重的变化规律.结果安蒙、利蒙、夏蒙、西蒙杂一代6月龄公母犊平均体重分别比同龄蒙古牛增加37.87 kg、40.60 kg、66.35 kg和43.71 kg,分别提高32.75%、35.11%、57.37%和38.0%.18月龄公母牛平均体重分别比同龄蒙古牛增加78.75 kg、96.73 kg、107.72 kg和100.59 kg,分别提高35.84%、44.02%、49.03%和45.78%.30月龄公母牛平均体重分别比同龄蒙古牛增加67.07 kg、84.86 kg、110.18 kg和116.26 kg,分别提高19.86%、25.13%、32.62%和34.42%.     

河流型水牛杂交改良德昌水牛的效果初报

为观察河流型水牛(摩拉水牛和尼里-拉菲水牛)与德昌水牛的杂交改良效果,笔者对杂交一代牛初生、1周岁、2周岁的体尺、体重进行测定,分析生长发育情况;同时测定杂交一代母水牛的产奶量、泌乳期,分析产奶性能情况.结果显示:杂交一代牛的平均初生重为42.58±6.32 kg,1周岁体重为285.22±15.09 kg,2周岁体重...     

湘南黄牛杂交组合筛选研究

为了确定适宜的湘南黄牛杂交组合,分别以安格斯、西门塔尔、短角、利木赞等4个肉用牛品种为父本,湘南黄牛为母本开展杂交试验,并对改良牛的体重和体尺进行测定,且进行了数据分析。结果表明:安本杂、西门塔尔、短角、利木赞牛对改良湘南黄牛的杂交优势十分明显,其中西门塔尔牛的改良效果最好。F1代公母牛初生、6月龄、12月龄、18月龄、24月龄体重较同龄湘南黄牛公母牛分别提高了72.62%和72.43%、50.25%和47.80%5、4.34%和59.46%、83.24%和74.68%、72.65%和76.23%,差异显著(P<0.05)。西门塔尔F1代公母牛24月龄体高、胸围、体斜长较同龄湘南黄牛公母牛提高了11.46%和12.02%、22.60%和23.51%、14.87%和15.54%,差异显著(P<0.05)。     

不同品种肉牛的育肥试验比较

为了优化适合内蒙古自治区的杂交模式,提高肉牛产业经济效益,试验选择体重340 kg左右、健康的14月龄西门塔尔×蒙古牛高代杂交牛(西蒙)、夏洛莱×蒙古牛高代杂交牛(夏蒙)公牛各5头,分为2组,在相同饲养条件下育肥,测定生产性能指标,并比较经济效益。结果表明:西蒙组牛平均每头增重、头均日增重分别为217.2,1.21 kg,比夏蒙组分别提高了20.0,0.11 kg,2组差异显著(P<0.05);西蒙组头均每千克增重所消耗的精料量、成本分别为3.30 kg、5.96元,比夏蒙组节省0.33 kg、0.59元,2组差异显著(P<0.05);西蒙组平均每头牛纯收益1 529.44元,比夏蒙组多收益257.18元,2组差异显著(P<0.05)。说明在相同饲养条件下,育肥西门塔尔×蒙古牛高代杂交牛比育肥夏洛莱×蒙古牛高代杂交牛节省饲料,相应地提高了经济效益。     

云南黄牛杂交改良效果分析

[目的]为了提高云南黄牛的生产性能,优选主要的杂交改良父本,开展云南黄牛杂交改良。[方法]用西门塔尔牛、短角牛、安格斯牛、海福特牛等分别与云南黄牛母本杂交,测定不同杂交组合后代初生、6月龄、12月龄、24月龄的体重体尺。[结果]云南黄牛经过杂交改良后,改良效果良好,杂交后代对云南高原的气候条件适应性良好。在农村饲养条件下,西×云杂一代牛初生重平均为24.57kg,6月龄体重平均为135.83kg,12月龄体重平均为196.21kg,24月龄体重平均为344.24kg,分别比本地黄牛提高74.13%,59.20%,56.53%和78.10%。短×云杂交一代牛初生重平均为22.28kg,6月龄体重平均为117.20kg,12月龄体重平均为193.56kg,24月龄体重平均为314.86kg,分别比本地黄牛提高57.90%,38.10%,54.21%和62.90%;安×云杂交一代牛犊牛初生重平均为21.21kg,6月龄体重平均为134.34kg,12月龄体重平均为196.18kg,24月龄体重平均为268.45kg,分别比本地黄牛提高50.32%,57.45%,56.51%和38.89%;海×云杂交一代牛初生重平均为22.78kg,6月龄体重平均为124.97kg,12月龄体重平均为190.52kg,24月龄体重平均为289.50kg,分别比本地黄牛提高61.45%,46.47%,51.99%和49.78%。[结论]西×云杂一代牛、短×云杂交一代牛、安×云杂交一代牛和海×云杂交一代牛生产性能显著提高,效益明显。     

昭乌达肉牛育种各阶段生产性能分析

昭乌达肉牛新品种育种是选择内蒙古赤峰本地蒙古牛与西门塔尔牛的杂交一代,组建育种核心群,进一步进行级进杂交,通过3代以上杂种肉牛的整群选育,横交固定,培育出的新品种。为了比较昭乌达肉牛与本地蒙古牛的生产性能,抽测了赤峰市辖区内40头本地蒙古牛、105头昭乌达肉牛在育种中不同代数西蒙杂交牛的初生、6月龄和18月龄的体重和体尺指标,并进行分析比较。结果表明,各阶段杂交牛与本地蒙古牛相比,其改良后代的体重、日增重和体尺均有提高,其中F3代各项指标均极显著(P0.01)高于本地蒙古牛。并且各生长阶段的体重、日增重和体尺等指标随着杂种后代代数的增加而增加,呈正相关。     

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.     

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.     

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     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in