Increased litter size in Rambouillet sheep: I. Estimation of genetic parameters.     

D F Waldron  D L Thomas 《Journal of animal science》1992,70(11):3333-3344

The variance and covariance components needed to estimate heritabilities of and genetic correlations among litter size, ovulation rate, scrotal circumference, and BW in a flock of Rambouillet sheep were estimated using REML via an expectation-maximization type algorithm. The heritability estimates from univariate analyses were .14, .21, .25, .36, and .15 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively, and average heritability estimates from bivariate analyses were .19, .20, .20, .34, and .10 for litter size, ovulation rate, scrotal circumference, 180-d BW of females, and 180-d BW of males, respectively. The genetic correlation between litter size and ovulation rate was near unity. Body weight in ewes had a moderate genetic correlation with both litter size (.22) and ovulation rate (.20) and a low residual correlation with both litter size (.03) and ovulation rate (.09). The genetic correlation between BW in rams and scrotal circumference was 0, whereas the residual correlation was .71. The genetic correlations of scrotal circumference with litter size and ovulation rate were -.25 and +.20, respectively.  相似文献   

Kinetics of hydration and effect of liquid uptake on specific gravity of small hay and silage particles.     

M A Wattiaux  D R Mertens  L D Satter 《Journal of animal science》1992,70(11):3597-3606

Kinetics of hydration of ground hay and silage particles (2-mm screen), determined by a pycnometric technique, was best described by a two- and one-pool exponential model, respectively. Fractional rates of hydration of the large pool, detected in hay particles only, and of the small pool present in both hay and silage particles averaged .135 and .021 min-1, respectively. When hydration was complete, liquid associated with particles averaged 1.16, 1.90, and .83 g/g of insoluble DM for bromegrass hay, alfalfa hay, and alfalfa silage, respectively. Functional specific gravity, which accounts for the effect of associated gas volume, averaged 1.54, 1.46, and 1.54, but unit specific gravity, calculated to include the effect of gases and liquid of hydration, averaged 1.22, 1.14, and 1.26 for bromegrass hay, alfalfa hay, and alfalfa silage, respectively. Preservation of forage as silage not only lowered gas volume, but also reduced water-holding capacity, both of which contribute to greater unit specific gravity and faster rate of escape from the rumen. In addition, estimates of unit specific gravity of approximately 1.2 indicate that even in the absence of associated gas, hydrated forage particles would tend to escape the rumen at a slower rate than that achieved by more dense particles.  相似文献   

Function of neutrophils and chemoattractant properties of fetal placental tissue during the last month of pregnancy in cows.     

M Hoedemaker  L A Lund  W C Wagner 《American journal of veterinary research》1992,53(9):1524-1529

Neutrophils were isolated from the blood of pregnant cows on days 255, 265, and 275 of pregnancy, and on the day of parturition (n = 5/group), and in addition, simultaneously from 4 ovariectomized healthy cows (control animals). Neutrophils were subjected to neutrophil function assays (chemotaxis against zymosan-activated serum, random migration, ingestion of 125I-iododeoxyuridine [IdUR]-labeled Staphylococcus aureus, iodination of proteins, cytochrome C reduction, antibody-independent and antibody-dependent cell-mediated cytotoxicity). Results were expressed as percentage of control animals. Fetal placental tissue (cotyledon), uterine wall tissue, and skeletal muscle were obtained from the principal animals on the aforementioned days via laparotomy, and tissue suspensions were prepared. Chemotaxis of neutrophils was tested against tissue supernatants. Compared with day 255, there was an increase in ingestion of 125I-IdUR-S aureus at parturition, whereas iodination of proteins and cytochrome C reduction were reduced on the day of calving. The other neutrophil functions tested did not change over time of gestation. Fetal placental and uterine wall tissue attracted neutrophils with uterine wall tissue having a tendency to be more potent than cotyledonary tissue. Skeletal muscle tissue did not attract neutrophils. There was no change in chemotaxis response of neutrophils evoked by intrauterine and uterine tissues over time of gestation. It was concluded that at parturition, neutrophil function is impaired with respect to their bactericidal effects, which may render the animal more susceptible to bacterial infections, and that the chemoattractant properties of fetal placental and uterine wall tissues are tissue-specific, at least when compared with skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

茶多酚(TP)对家禽免疫功能的研究     

詹勇  李进昌  杨贤强 《浙江大学学报(农业与生命科学版)》1992,(4)

选用14日龄健康的海佩科内用仔鸡48羽,随机分成试验(24羽)和对照(24羽)两组.试验组在饲粮中添加0.25％的茶多酚(TP),研究TP对鸡免疫功能的作用.试验结果表明,TP对自然感染法氏囊病鸡,有明显提高(p<0.05)鸡血液中红细胞C_(3b)受体和免疫复合物的含量及保护鸡脾脏正常的免疫功能,同时也发现TP对公母鸡法氏囊的重量有不同影响.本试验表明,TP具有提高家禽免疫功能的作用.  相似文献   

Proliferative response of mammary gland mononuclear cells to recombinant bovine interleukin-2.     

P M Torre  P K Konur  S P Oliver 《Veterinary immunology and immunopathology》1992,32(3-4):351-358

Methods of augmenting bovine mononuclear cell responsiveness during physiological transitions of the udder may enhance resistance of the mammary gland to intramammary infections. Interleukin-2 is required for proliferation of T-lymphocytes and may contribute to B-lymphocyte proliferation. Recombinant bovine interleukin-2 (rBoIL-2) was evaluated as a potential immunoenhancer of bovine mammary gland mononuclear cells. Bovine mononuclear cells were isolated from five primiparous Holstein cows at 14-18 and 28-32 days of involution and at 7-13 days prior to parturition. Bovine blood and mammary gland mononuclear cells were highly responsive to rBoIL-2. Response of mammary gland mononuclear cells to rBoIL-2 was comparable with response of blood mononuclear cells. These data suggest that rBoIL-2 may be an effective immunoenhancer of bovine mononuclear cells during the non-lactating and prepartum periods.  相似文献   

Use of netting and whitewash spray to protect papaya plants against Nivun Haamir (NH)-dieback disease     

A. Franck  M. Bar-Joseph 《Crop Protection》1992,11(6):525-528

A disease causing the decline of papaya (Carica papaya) plants was noticed in the Jordan Valley in 1982. The disease caused severe yellowing of the upper leaves and dieback of the apex. The disease was not transmissible mechanically and continued efforts to associate viruses and viroids have so far been unsuccessful. Epidemiological observations suggested that the disease is airborne and probably caused by a mollicute. In order to test this hypothesis, plots were covered by an insect-proof net and with white nets providing 15, 30 and 50% shade. The 30%, 50% and insect-proof nettings provided complete protection, and the 15% netting reduced disease incidence to <2%, compared with>37% in the uncovered control plot. Spraying plants at weekly intervals with a commercial whitewash solution was also found to be effective in reducing disease incidence. The advantages of using a range of netting field treatments as a simple means for obtaining information on the epidemiological nature of a new disease are described.  相似文献   

Pulmonary artery and aortic pressure changes during high intensity treadmill exercise in the horse: effect of frusemide and phentolamine.     

B K Erickson  H H Erickson  J R Coffman 《Equine veterinary journal》1992,24(3):215-219

Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in heart rate relative to control only early in exercise but not during later, more strenuous, exercise. Phentolamine had no statistically significant effect on AP, PAP, or PCV, but a significant reduction was observed between 180 and 230 sec of exercise when PAP and AP were standardised against heart rate. Frusemide did not prevent horses from haemorrhaging during exercise in this study. Treatment with phentolamine did not sufficiently reduce the PAP and AP to test our hypothesis that a reduction in PAP and AP would eliminate EIPH.  相似文献   

The effect of porcine somatotropin supplementation in pigs on the lipid profile of subcutaneous and intermuscular adipose tissue and longissimus muscle.     

S L Clark  R C Wander  C Y Hu 《Journal of animal science》1992,70(11):3435-3442

The effect of porcine somatotropin (pST) on the lipid profiles of adipose tissue and muscle was investigated. Sixteen crossbred barrows were injected daily with either 3 mg of pST or a placebo. After slaughter, total lipid and fatty acid composition of raw subcutaneous (SC) adipose and intermuscular (IM) adipose tissue and longissimus muscle were determined. The SC adipose tissue from pST-treated pigs had a 7.5% decrease in total lipid content; specific fatty acids 16:0, 18:0, and 18:1(n-9)c decreased most. The IM fat from pST-treated pigs had lower levels of 16:0 and 20:0. There was no effect of pST treatment on the lipid profile of the longissimus muscle. The data suggest that pST treatment produces small but significant changes in the saturated fatty acid content of adipose tissue in pigs.  相似文献   

Abattoir condemnation of pigs and its economic implications in Singapore     

C K Tiong  C S Bin 《The British veterinary journal》1989,145(1):77-84

Losses due to mortality and rejection of carcases and viscera in a population of 2,959,607 pigs admitted for slaughter in Singapore abattoirs between 1984 and 1986 were studied. Mortality losses were 2822 pigs (9.5 per 10,000 admissions) while 3039 whole carcases (10.3 per 10,000 admissions) were condemned at post-mortem examination. The main reason for rejection of carcases was pyaemia (30.3%). Kidneys and livers were the two main organs of economic value rejected. Rejection of kidneys was primarily due to nephritis (54.8%) while liver condemnation was mainly due to cirrhosis (38.6%). The financial loss from abattoir rejection was S$5.27 millions or S$1.78 per pig admitted. The value of abattoir condemnation data as a tool in preventive medicine is discussed.  相似文献   

Serum amyloid A protein (SAA) in horses: objective measurement of the acute phase response   总被引：1，自引：0，他引：1  

M B Pepys  M L Baltz  G A Tennent  J Kent  J Ousey  P D Rossdale 《Equine veterinary journal》1989,21(2):106-109

A sensitive and precise immunoassay for equine serum amyloid A protein (SAA) was established and used to determine, for the first time, the circulating concentration of this protein in health and disease. As in other species, equine SAA was present only at trace levels in healthy animals but behaved as an extremely sensitive and rapidly responding acute phase reactant following most forms of tissue injury, infection and inflammation, objectively reflecting the extent and activity of disease. Measurements of SAA should make a significant contribution to diagnosis and management of viral and bacterial infection in horses, and routine serial assays could provide an objective criterion for monitoring prospectively the general health of horses in training and racing.  相似文献