枣粉与包被蛋氨酸对育肥牛生长性能、养分表观消化率、瘤胃发酵和血清生化指标的影响

本试验旨在研究饲粮添加枣粉(JP)和包被蛋氨酸(CMet)对育肥期肉牛生长性能、养分表观消化率、瘤胃发酵和血清生化指标的影响。采用双因子试验设计,试验因素分别为JP(JP替代饲粮玉米比例为0或15%,JP-/JP+)和CMet(饲粮添加0或1.08 g/kg蛋氨酸有效成分,CMet-/CMet+)。将20头月龄与体重相近的育肥期肉牛(西门塔尔×本地黄牛)随机分为4组,分别饲喂基础饲粮、基础饲粮+JP、基础饲粮+CMet以及基础饲粮+JP+CMet,每组5个重复,每个重复1头牛。试验期共70 d,其中预试期10 d,正试期60 d。结果表明：1)饲粮添加JP显著提高了干物质采食量和平均日增重(P <0.05);而添加CMet仅显著提高了平均日增重(P <0.05);JP与CMet对生长性能互作效应不显著(P>0.05)。2)饲粮添加JP显著提高了粗蛋白质、酸性洗涤纤维和非纤维碳水化合物表观消化率(P<0.05);饲粮添加CMet则显著提高了粗蛋白质、有机物和非纤维碳水化合物表观消化率(P<0.05);JP与CMet对粗蛋白质和非纤维碳水化合物表观消化率互作效...     

饲粮添加过瘤胃半胱氨酸对育成期梅花鹿生长性能、营养物质表观消化率和血清生化指标的影响

本试验旨在研究饲粮添加过瘤胃半胱氨酸对育成期梅花鹿生长性能、营养物质表观消化率和血清生化指标的影响。采用单因素随机区组试验设计,将12头7月龄雄性梅花鹿仔鹿分为4组(每组3个重复,每个重复1只),组间体重差异不显著。对照组(Ⅰ组)饲喂基础饲粮,试验组分别饲喂额外添加1.25(Ⅱ组)、2.50(Ⅲ组)和5.00 g·kg^-1(Ⅳ组)过瘤胃半胱氨酸(有效成分51.70%)的试验饲粮。试验预饲期15 d,正试期112 d。结果表明,1)与Ⅰ组相比,添加过瘤胃半胱氨酸Ⅲ组总增重和平均日增重显著提高(P<0.05),Ⅲ组料重比显著降低(P<0.05);2)与Ⅰ组相比,添加过瘤胃半胱氨酸各组粗蛋白质、钙和磷表观消化率显著提高(P<0.05),Ⅲ组干物质和有机物表观消化率显著提高(P<0.05);3)与Ⅰ组相比,添加过瘤胃半胱氨酸Ⅱ组和Ⅲ组甘氨酸表观消化率显著提高(P<0.05),各组半胱氨酸、蛋氨酸、丝氨酸、赖氨酸、苏氨酸、缬氨酸、异亮氨酸、亮氨酸、精氨酸、苯丙氨酸、组氨酸、天冬氨酸、酪氨酸、谷氨酸、丙氨酸和脯氨酸表观消化率显著提高(P<0...     

饲粮添加包被蛋氨酸和包被叶酸对杜寒杂交二代公羔生长性能、养分消化代谢和瘤胃微生物蛋白质合成的影响

本试验旨在研究饲粮添加包被蛋氨酸(coated methionine,CM)和包被叶酸(coated folic acid,CFA)对杜寒杂交二代公羔生长性能、养分消化代谢及瘤胃微生物蛋白质合成的影响。采用2×2完全随机试验设计,试验因素为按照试验动物体重添加CFA(0 mg,CFA-或4 mg·(kg·d)~(-1),CFA+)和CM(0 g,CM-或0.1 g·(kg·d)~(-1),CM+)。将40只体重相近((30.08±1.34) kg)的4月龄杜寒杂交二代公羔随机分为4组,分别饲喂基础日粮(CM-CFA-)、基础日粮+CFA 4 mg·(kg·d)~(-1)(CM-CFA+)、基础日粮+CM 0.1 g·(kg·d)~(-1)(CM+CFA-)、基础日粮+CFA 4 mg·(kg·d)~(-1)+CM 0.1 g·(kg·d)~(-1)(CM+CFA+)。试验期85 d,其中预试期15 d,正试期70 d,在试验期结束前10 d开展消化代谢试验。试验结果表明:1)饲粮添加CFA显著提高了1～30 d平均日增重和饲料转化率(P0.05),而添加CM仅显著提高了1～30 d饲料转化率(P=0.036),对1～30 d平均日增重无显著影响(P0.05);饲粮中添加CFA、CM显著提高了杜寒杂交二代公羔31～60 d和1～60 d平均日增重及相应阶段饲料转化率(P0.05),二者对1～60 d饲料转化率具有显著互作效应(P=0.007);2)饲粮添加CFA显著提高了干物质、有机物、中性洗涤纤维和酸性洗涤纤维的表观消化率(P0.05),饲粮添加CM有提高有机物表观消化率的趋势(P=0.066)及增加干物质消化率的趋势(P=0.095),二者对养分消化率无显著互作效应(P0.05);3)饲粮添加CFA、CM显著降低了尿能排出量,显著提高了能量消化率和代谢率(P0.05);通过显著降低粪氮、尿氮及总排泄氮(P0.05),从而显著提高了氮的表观消化率和沉积氮水平(P0.05),且二者同时添加对减少氮排泄、提高氮消化率有显著互作效应(P0.05);4)饲粮添加CM、CFA显著提高嘌呤衍生物的尿排泄量,提高瘤胃微生物蛋白质合成量(P0.05)。饲粮添加CM、CFA提高干物质和有机物表观消化率,改善总能消化率和代谢率,增加氮表观消化率和氮沉积量,促进杜寒杂交二代公羔的生长。     

纳豆芽孢杆菌和枯草芽孢杆菌对绵羊生长性能、消化性能和血清生化指标的影响

为研究纳豆芽孢杆菌(Bacillus natto,BN)和枯草芽孢杆菌(Bacillus subtilis,BS)对绵羊生长性能、营养物质表观消化率和血清生化指标的影响,试验将体重相近的30只羊分为基础饲粮组(CK组)、基础饲粮+BN组(A组)、基础饲粮+BN+BS组(B组),每组10只。结果表明:(1)与CK组相比,A组平均日增重(ADG)提高32.29g(P<0.05),B组提高68.00g(P<0.01),A组和B组之间差异不显著(P>0.05)。(2)B组粗蛋白质的表观消化率比CK组显著提高16.31%(P<0.01),A组与CK组之间差异不显著(P>0.05)。(3)与CK组相比,A组血清尿素氮降低23.44%(P>0.05)、B组显著下降44.69%(P<0.01)。综上,在本试验条件下,饲粮中添加BN可显著提高绵羊的ADG,但复合添加BS的效果更好。同时,饲粮中复合添加BN和BS可显著提高绵羊对粗蛋白质的表观消化率、降低血清尿素氮含量。     

过瘤胃蛋氨酸对黔北麻羊生长性能、养分表观消化率、血浆生化指标及瘤胃发酵的影响

本试验旨在研究过瘤胃蛋氨酸(RPMet)对黔北麻羊生长性能、养分表观消化率、血浆生化指标及瘤胃发酵的影响。选择18只体况良好、体重[(27.08±2.92)kg]和年龄相近的黔北麻羊,随机分为3组,每组6个重复,每个重复1只羊。对照组饲喂基础饲粮,Ⅰ、Ⅱ组在基础饲粮中每只羊分别添加5、10g/d的RPMet。预试期14d,正试期7d。结果表明:1)各组山羊生长性能指标差异不显著(P>0.05)。2)Ⅱ组粗蛋白质表观消化率显著高于对照组(P<0.05),各组其他养分表观消化率差异不显著(P>0.05)。3)各组血浆生化指标差异不显著(P>0.05)。4)各组瘤胃pH及挥发性脂肪酸浓度差异不显著(P>0.05)。由此可见,在现有饲养标准的基础上,饲粮中添加10g/dRPMet可提高黔北麻羊粗蛋白质表观消化率,且不影响生长性能、血浆生化指标及瘤胃发酵。     

过瘤胃保护脂肪对肉牛增重和营养物质表观消化率的影响

为研究过瘤胃脂肪对肥育肉牛增重和营养物质消化的影响,将87头西杂肉牛分成2组,试验组在对照组的日粮基础上补饲300g过瘤胃脂肪,结果表明:日粮中添加过瘤胃脂肪可显著提高肉牛日增重和饲料转化效率(P<0.05),试验组和对照组的日增重分别为1255g和1113g。过瘤胃脂肪添加对全消化道干物质(DM)、有机物(OM)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)消化率影响不显著(P>0.05),试验组全消化道粗脂肪的表观消化率显著高于对照组(P<0.05),但试验组日粮粗蛋白质消化率显著低于对照组(P<0.05)。     

溶血磷脂对安格斯肉牛生长性能、养分表观消化率和血清生化指标的影响

本研究旨在明确在含过瘤胃脂肪饲粮中添加溶血磷脂对肉牛生长性能、养分表观消化率和血清生化指标的影响。选用健康且体重[(450.2±22.9) kg]相近的安格斯公牛12头,随机分为2组,每组6头。其中,对照组饲喂基础饲粮,溶血磷脂组饲喂试验饲粮[在基础饲粮中额外添加0.05%(干物质基础)溶血磷脂]。试验期为74 d,其中前14 d为预试期,后60 d为正试期。结果表明：1)溶血磷脂组肉牛的平均日增重显著高于对照组(P<0.05),且体重有高于对照组的趋势(P<0.10),但平均日采食量2组间未出现显著差异(P>0.05)。2)与对照组相比,溶血磷脂极显著提高了粗脂肪的表观消化率(P<0.01),显著提高了粗蛋白质的消化率(P<0.05),而干物质、中性洗涤纤维和酸性洗涤纤维的表观消化率均未出现显著变化(P>0.05)。3)在血清抗氧化指标中,与对照组相比,溶血磷脂显著降低了丙二醛含量(P<0.05),但并未对其余指标产生显著影响(P>0.05)。4)在血清代谢指标中,溶血磷脂显著降低了总胆固醇含量(P<0.05),且使碱性磷酸酶活性...     

饲粮直链/支链淀粉和淀粉酶对肉鸡生长性能的影响及其互作效应研究

本试验旨在研究饲粮直链/支链淀粉和淀粉酶对肉鸡生长性能和营养物质表观消化率的影响。试验采用4×3双因子设计,选用1日龄爱拔益加(AA)肉仔鸡960只,随机分为12个组,每组5个重复,每个重复16羽肉鸡,饲粮直链/支链淀粉分别为0.11、0.23、0.35、0.47,淀粉酶的添加量分别为0、3000、6000U/kg。试验期为21d。试验测定了肉鸡生长性能和营养物质表观消化率。结果表明:1)直链/支链淀粉为0.23的饲粮组肉鸡的平均日增重显著提高(P<0.05),料重比以直链/支链淀粉为0.47的饲粮组最高(P<0.05),其他组间差异不显著(P>0.05);饲粮中添加6000U/kg淀粉酶显著降低肉鸡平均日增重(P<0.05),但对料重比影响不显著(P>0.05);二者的互作效应不显著(P>0.05)。2)能量、粗蛋白质、干物质、粗脂肪以及钙表观消化率以直链/支链淀粉为0.11的饲粮组最高(P<0.05),直链/支链淀粉为0.47的饲粮组最低(P<0.05);饲粮中添加淀粉酶对营养物质表观消化率影响不显著(P>0.05);二者的互作效应对营养物质表观消化率影响显著(P<0.05)。综上所述,饲喂直链/支链淀粉为0.23和淀粉酶添加量为3 000 U/kg的饲粮可提高肉鸡的生长性能。     

苯甲酸与二甲酸钾对獭兔生长性能、胃肠内容物pH和养分表观消化率的影响

试验旨在研究饲粮中添加不同配比苯甲酸和二甲酸钾对獭兔生长性能、屠宰性能、胃肠道内容物pH和养分表观消化率的影响。选取35日龄健康獭兔200只,按照体重和性别随机分为4组,每组50个重复,每个重复1只。对照组饲喂基础饲粮,试验组分别在基础日粮中添加1.0%二甲酸钾+0.2%苯甲酸（试验Ⅰ组）、0.8%二甲酸钾+0.3%苯甲酸（试验Ⅱ组）、0.6%二甲酸钾+0.4%苯甲酸（试验Ⅲ组）。预试期5d,正试期56 d。结果表明：试验Ⅰ组和试验Ⅱ组末重、平均日增重均高于对照组（P<0.05、P<0.01）,耗料增重比均低于对照组（P<0.01）;试验Ⅲ组平均日增重高于对照组（P<0.05）,耗料增重比低于对照组（P<0.05）;全净膛重、半净膛重、全净膛率、半净膛率、胃和盲肠内容物pH各组间均差异不显著;试验Ⅰ组粗蛋白质、粗脂肪和中性洗涤纤维的表观消化率均高于对照组（P<0.05、P<0.01）。由此可见,獭兔饲粮中添加二甲酸钾和苯甲酸可以提高獭兔平均日增重、降低耗料增重比,提高獭兔对饲粮中粗蛋白质、粗脂肪以及中性洗涤纤维的表观消化率。本试验条件下,獭兔饲...     

饲粮添加包被蛋氨酸和包被叶酸对杜寒杂交二代公羔生长性能、养分消化代谢和瘤胃微生物蛋白质合成的影响

本试验旨在研究饲粮添加包被蛋氨酸（coated methionine,CM）和包被叶酸（coated folic acid,CFA）对杜寒杂交二代公羔生长性能、养分消化代谢及瘤胃微生物蛋白质合成的影响。采用2×2完全随机试验设计,试验因素为按照试验动物体重添加CFA（0 mg,CFA-或4 mg·（kg·d）^-1,CFA+）和CM（0 g,CM-或0.1 g·（kg·d）^-1,CM+）。将40只体重相近（（30.08±1.34）kg）的4月龄杜寒杂交二代公羔随机分为4组,分别饲喂基础日粮（CM-&CFA-）、基础日粮+CFA 4 mg·（kg·d）^-1（CM-&CFA+）、基础日粮+CM 0.1 g·（kg·d）^-1（CM+&CFA-）、基础日粮+CFA 4 mg·（kg·d）^-1+CM 0.1 g·（kg·d）^-1（CM+&CFA+）。试验期85 d,其中预试期15 d,正试期70 d,在试验期结束前10 d开展消化代谢试验。试验结果表明：1）饲粮添加CFA显著提高了1~30 d平均日增重和饲料转化率（P<0.05）,而添加CM仅显著提高了1~30 d饲料转化率（P=0.036）,对1~30 d平均日增重无显著影响（P>0.05）;饲粮中添加CFA、CM显著提高了杜寒杂交二代公羔31~60 d和1~60 d平均日增重及相应阶段饲料转化率（P<0.05）,二者对1~60 d饲料转化率具有显著互作效应（P=0.007）;2）饲粮添加CFA显著提高了干物质、有机物、中性洗涤纤维和酸性洗涤纤维的表观消化率（P<0.05）,饲粮添加CM有提高有机物表观消化率的趋势（P=0.066）及增加干物质消化率的趋势（P=0.095）,二者对养分消化率无显著互作效应（P>0.05）;3）饲粮添加CFA、CM显著降低了尿能排出量,显著提高了能量消化率和代谢率（P<0.05）;通过显著降低粪氮、尿氮及总排泄氮（P<0.05）,从而显著提高了氮的表观消化率和沉积氮水平（P<0.05）,且二者同时添加对减少氮排泄、提高氮消化率有显著互作效应（P<0.05）;4）饲粮添加CM、CFA显著提高嘌呤衍生物的尿排泄量,提高瘤胃微生物蛋白质合成量（P<0.05）。饲粮添加CM、CFA提高干物质和有机物表观消化率,改善总能消化率和代谢率,增加氮表观消化率和氮沉积量,促进杜寒杂交二代公羔的生长。     

Concentrations of strontium,barium, cadmium,copper, zinc,manganese, chromium,antimony, selenium,and lead in the liver and kidneys of dogs according to age,gender, and the occurrence of chronic kidney disease

This study was conducted to measure the concentrations of strontium (Sr), barium (Ba), cadmium (Cd), copper (Cu), zinc (Zn), manganese (Mn), chromium (Cr), antimony (Sb), selenium (Se), and lead (Pb) in canine liver, renal cortex, and renal medulla, and the association of these concentrations with age, gender, and occurrence of chronic kidney disease (CKD). Tissues from 50 dogs were analyzed using inductively coupled plasma mass spectrometry. Cu, Zn, and Mn levels were highest in the liver followed by the renal cortex and renal medulla. The highest Sr, Cd, and Se concentrations were measured in the renal cortex while lower levels were found in the renal medulla and liver. Female dogs had higher tissue concentrations of Sr (liver and renal medulla), Cd (liver), Zn (liver and renal cortex), Cr (liver, renal cortex, and renal medulla), and Pb (liver) than male animals. Except for Mn and Sb, age-dependent variations were observed for all element concentrations in the canine tissues. Hepatic Cd and Cr concentrations were higher in dogs with CKD. In conclusion, the present results provide new knowledge about the storage of specific elements in canine liver and kidneys, and can be considered important reference data for diagnostic methods and further investigations.     

Antibacterial action of combinations of oxytetracycline, dimethyl sulfoxide, and EDTA-tromethamine on Proteus, Salmonella, and Aeromonas

Antibacterial effects against Proteus mirabilis, Salmonella typhimurium, and Aeromonas hydrophila were obtained with subminimal inhibitory concentrations of oxytetracycline and EDTA-tromethamine. Antibacterial effects were not observed with subminimal inhibitory concentrations of dimethyl sulfoxide plus oxytetracycline or with dimethyl sulfoxide plus EDTA-tromethamine. Using a 2-dimensional Microtiter checkerboard technique, inhibitory activities of the various combinations of solutions were studied, and isobolograms were plotted. A synergistic effect was seen with combinations of oxytetracycline and EDTA-tromethamine. The greatest synergistic effect was observed when the mixture was caused to react with P mirabilis. These findings were confirmed by kinetic studies of microbial death, using one-fourth minimal inhibitory concentrations of these preparations.     

Comparative cardiovascular, analgesic, and sedative effects of medetomidine, medetomidine-hydromorphone, and medetomidine-butorphanol in dogs

OBJECTIVE: To compare sedative, analgesic, and cardiopulmonary effects after IV administration of medetomidine (20 microg/kg), medetomidine-hydromorphone (20 microg of medetomidine/kg and 0.1 mg of hydromorphone/kg), and medetomidine-butorphanol (20 microg of medetomidine/kg and 0.2 mg of butorphanol tartrate/kg) in dogs. ANIMALS: 6 dogs healthy mixed-breed dogs. PROCEDURE: Instruments were surgically inserted, and heart rate (HR), respiratory rate (RR), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), core body temperature, and cardiac output (CO) were measured 0, 5, 10, 15, 30, 45, and 60 minutes after injection. Cardiac index (CI), stroke volume (SV), stroke index (SI), systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were calculated. Arterial samples for blood gas analysis were collected 0, 15, and 45 minutes after injection. Intensity of analgesia, degree of sedation, and degree of muscle relaxation were evaluated at aforementioned time points and 75, 90, 120, 150, 180, and 210 minutes after injection. RESULTS: Administration of medetomidine, medetomidine-hydromorphone, and medetomidine-butorphanol was associated with increases in SAP, MAP, DAP, MPAP, PCWP, CVP, SVR, PVR, core body temperature, and PaCO2 and decreases in HR, CO, CI, SV, SI, RR, pH, and PaO2. Clinically important differences were not detected among treatments. Medetomidine-hydromorphone and medetomidine-butorphanol provided a longer duration of sedation and better quality of analgesia, compared with medetomidine alone. CONCLUSIONS AND CLINICAL RELEVANCE: Medetomidine-hydromorphone or medetomidine-butorphanol is associated with improved analgesia and sedation but has cardiopulmonary effects comparable to those for medetomidine alone.     

Toxicology of selected pesticides, drugs, and chemicals. Anticoagulant, cholecalciferol, and bromethalin-based rodenticides

The control of rodent pests is a continuing goal of mankind. To this end, a multitude of rodenticides have been produced, each designed to kill rodents by exerting their toxic effects on various body systems. As examples, veterinarians have had to manage companion animal poisonings due to anticoagulant, sodium fluoroacetate (compound 1080), thallium, barium carbonate, and zinc phosphide-based rodenticides. Many of these rodenticides were introduced because of their anticipated safety in relation to nontarget species; unfortunately, this has not been the case. Veterinarians must attempt to identify the specific rodenticide involved in poisoning cases. Therapeutic success in these poisonings is often more dependent upon symptomatic and supportive care rather than the use of antidotal therapy.     

Echocardiography, electrocardiography, and radiography of cats with dilatation cardiomyopathy, hypertrophic cardiomyopathy, and hyperthyroidism

The echocardiographic, ECG, and radiographic findings of sequentially examined cats with dilatation cardiomyopathy (DCM, n = 7), hypertrophic cardiomyopathy (HCM, n = 8), and hyperthyroidism (HT, n = 20) were compared with those of healthy control cats (n = 11). Cats with DCM were easily differentiated from healthy cats by echocardiography and from cats with HCM and HT by a dilated left ventricle at end-diastole with a mean +/- SD of 2.20 +/- 0.36 cm, reduced fractional shortening (2.9% +/- 3.7%), reduced aortic amplitude (0.07 +/- 0.05 cm), reduced left ventricular wall amplitude (0.09 +/- 0.09 cm), and increased E-point septal separation (0.83 +/- 0.29 cm). The cats with HCM were most consistently recognized echocardiographically by increased left ventricular wall thickness at end-diastole (0.75 +/- 0.12 cm). Some cats with HT had abnormal echocardiograms with left ventricular wall hypertrophy. These cats could usually be differentiated from the cats with HCM because of normal or increased ventricular wall amplitude, aortic amplitude, or percentage of thickening of the left ventricular wall and interventricular septum. Left atrial enlargement (left atrial diameter greater than 1.57 cm or left atrium/aorta greater than 1.75) was commonly detected by the echocardiogram in cats with DCM, HCM, or HT. The echocardiogram was helpful in differentiating the type of cardiomyopathy (DCM, HCM, or HT) when plain thoracic radiographs indicated that cardiomegaly existed. The ECG may have indicated incorrectly that there was left ventricular enlargement in some cats with HT, and it did not indicate consistently that left ventricular enlargement existed when present in cats with DCM or HCM. The ECG was a poor indicator of left atrial enlargement in all cats.     

Comparisons of Angus, Charolais, Galloway, Hereford, Longhorn, Nellore, Piedmontese, Salers, and Shorthorn breeds for weight, weight adjusted for condition score, height, and condition score of cows

Breed differences for weight (CW), height (CH), and condition score (CS) were estimated from records (n = 12,188) of 2- to 6-yr-old cows (n = 744) from Cycle IV of the U.S. Meat Animal Research Center's Germplasm Evaluation (GPE) Program. Cows were produced from mating Angus and Hereford dams to Angus, Hereford, Charolais, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, and Salers sires. Samples of Angus and Hereford sires were 1) reference sires born from 1962 through 1970 and 2) 1980s sires born in 1980 through 1987. The mixed model included cow age, season of measurement and their interactions, year of birth, pregnancy-lactation code (PL), and breedgroup as fixed effects for CW and CS. Analyses of weight adjusted for condition score included CS as a linear covariate. The model for CH excluded PL. Random effects were additive genetic and permanent environmental effects associated with the cow. Differences among breed groups were significant (P < 0.05) for all traits and were maintained through maturity with few interchanges in ranking. The order of F1 cows for weight was as follows: Charolais (506 to 635 kg for different ages), Shorthorn and Salers, reciprocal Hereford-Angus (HA) with 1980s sires, Nellore, HA with reference sires, Galloway, Piedmontese, and Longhorn (412 to 525 kg for different ages). Order for height was as follows: Nellore (136 to 140 cm), Charolais, Shorthorn, Salers, HA with 1980s sires, Piedmontese, Longhorn, Galloway and HA with reference sires (126 to 128 cm). Hereford and Angus cows with reference sires were generally lighter than those with 1980s sires. In general, breed differences for height followed those for weight except that F1 Nellore cows were tallest, which may in part be due to Bos taurus-Bos indicus heterosis for size.     

Genetic parameters among weight, prolificacy, and wool traits of Columbia, Polypay, Rambouillet, and Targhee sheep

Genetic parameters for Columbia, Polypay, Rambouillet, and Targhee sheep were estimated using REML with animal models for prolificacy, weight, and wool traits. All bivariate analyses included a covariance between additive genetic effects for the two traits plus appropriate additional covariances. Number of observations by breed ranged from 5,140 to 7,095 for prolificacy traits, from 7,750 to 9,530 for weight traits, and from 4,603 to 34,746 for wool traits. Heritability estimates ranged from .03 to .11 for prolificacy traits (litter size at birth and litter size at weaning), from .09 to .26 for weight traits (birth weight and average daily gain), and from .25 to .53 for wool traits (fleece weight, fleece grade and staple length). Estimates of direct genetic correlations among prolificacy and among weight traits were positive and ranged from .58 to 1.00 and .18 to 1.00, respectively. Estimates of direct genetic correlation between fleece weight and staple length were positive (.50 to .70) but were negative between fleece weight and fleece grade (-.60 to -.34) and between staple length and fleece grade (-.72 and -.40). Prolificacy and wool traits were essentially uncorrelated. Weight and prolificacy traits were slightly positively correlated. Weight traits had a moderate positive direct genetic correlation with fleece weight and staple length, but were uncorrelated with fleece grade. These estimates of genetic parameters between prolificacy, weight, and wool traits can be used to construct multiple-trait selection indexes for dual-purpose sheep.