Ovarian follicular characteristics, embryo recovery, and embryo viability in heifers fed high-fat diets and treated with follicle-stimulating hormone.

Postpubertal beef heifers (n = 55) were used to examine the effects of high-fat diets, independently of energy intake, on nonesterified fatty acid and lipoprotein metabolic patterns, ovarian follicular dynamics, and embryo recovery/viability after FSH superstimulation. High-lipid (HL) diets (5.4% added fat) increased (P < .01) serum concentrations of cholesterol, but not of nonesterified fatty acids, during the 35-d period before FSH treatment. Development of medium-sized (5 to 9.9 mm) follicles was enhanced (P < .05) during this period in heifers fed the HL diet. The HL diet increased total cholesterol (P < .05) and progesterone (P = .14) concentrations in follicular fluid obtained at ovariectomy (n = 10) 60 h after the onset of FSH treatment, but neither estradiol-17 beta nor androstenedione was affected. Granulosa cells recovered from FSH-induced, estrogen-active follicles in heifers fed the HL diet produced greater quantities of progesterone (P = .06) and less estradiol-17 beta (P < .05) in vitro than did granulosa cells from heifers fed the normal lipid diet. Dietary treatment did not influence FSH-stimulated recruitment of medium and large follicles, number of ovulations, embryo recovery, or embryo viability. Data suggest that increments in dietary fat intake can alter specific aspects of ovarian steroidogenic potential and can increase the population of medium-sized follicles theoretically available for maturation and harvest during the estrous cycle. However, conditions that limited the latter process in the current experiment are not understood and require further investigation.     

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

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.     

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

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.     

Surgical treatment of dorsal cortical fractures of the third metacarpal bone in thoroughbred racehorses: 53 cases (1985-1989).

Between January 1985 and May 1989, 53 Thoroughbred horses (mean age 3.2 years) were surgically treated for dorsal cortical fractures of the third metacarpal bone (MC III). All horses were treated with cortical drilling through the fracture line (osteostixis). Diagnosis of the fractures was confirmed by xeroradiography. Lifetime racing records were obtained for all horses. Forty-seven horses returned to racing after surgery (89%). The mean time between surgery and the first race was 6.8 months. Horses had a mean of 10.9 starts before surgery and 16.1 starts after surgery. The mean earnings per start before surgery was $6,459 and after surgery was $5,685. Of the 47 horses that raced after surgery, 70% raced at the same class or improved. Complications related to surgery were seen in 10 horses. Two horses had a second fracture of MC III at the same site, and were again treated by osteostixis, after which both horses returned to competition. Fractured drill bits were left in the MC III of 4 horses. One of these horses had catastrophic failure of MC III. Two horses developed subcutaneous infections and 2 horses had catastrophic failure of MC III in the surgically treated limb. Osteostixis appears to be an effective treatment for returning horses affected with dorsal cortical fractures to racing.     

Analysis of glycoprotein I (gI) negative and aberrant pseudorabies viral diagnostic isolates.

Glycoprotein I (gI) phenotypes and genotypes of 4 pseudorabies viral diagnostic isolates were evaluated by use of in vitro DNA amplification, monoclonal antibody binding, gI-specific serodiagnostic responses, and in vivo virulence approaches. Three viruses were avirulent and did not elicit gI-specific serologic responses, react with gI-specific monoclonal antibodies, or contain gI epitope-encoding DNA sequences. The fourth virus was virulent and did elicit a gI-specific serodiagnostic response. Compared with reference virulent pseudorabies viruses, however, the fourth isolate had reduced reactivity with a group of gI monoclonal antibodies and had a single nucleotide sequence substitution with a corresponding putative amino acid change in the epitopically dominant portion of the gI molecule. Presumably, the first 3 isolates represented diagnostic recoveries of viruses derived from gI-deleted modified-live pseudorabies viral vaccines, whereas the fourth isolate was a virulent but gI-aberrant wild-type virus. Thoroughly assessing the gI status of pseudorabies viral diagnostic isolates was considered to be essential in evaluating the epidemiologic importance of these viruses and in monitoring the validity of gI-based vaccine companion tests now used worldwide in pseudorabies control and eradication programs.     

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

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.     

Large granular lymphoma in an FIV-positive and FeLV-negative cat

The clinical course of a feline leukaemia virus (FeLV)-negative and feline immunodeficiency virus (FIV)-positive cat affected with a large granular lymphocyte lymphoma is presented. Cyto-logical examination showed neoplastic cells in the pleural effusion and in two abdominal masses. Bone marrow and peripheral blood were moderately involved and chemotherapy was used to control the tumour. Cytochemistry, immunohis-tochemistry and ultrastructural studies were applied to define the cellular lineage; cytochemistry suggested a T-cell lineage.     

Duck lymphocytes. VI. Requirement for phagocytic and adherent cells in lymphocyte transformation.

Preparations of duck (Anas platyrhynchos) spleen and blood lymphocytes depleted of cells capable of phagocytosing carbonyl iron gave lower transformation responses to the mitogens phytohaemagglutinin (PHA), concanavalin A (Con A), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), lentil lectin (LL) and phorbol ester (PMA) than intact cell preparations. When cell populations were fractionated on the basis of their adherence to plastic, it was found that the adherent cells were responsive to PHA, Con A, BSS, WGA and PMA, while the non-adherent cells responded to LL. These observations confirm the expected requirement for phagocytic accessory cells in the induction of in vitro mitogen-driven duck lymphocyte responses. The responses of plastic-adherent populations of cells to most mitogens are believed to reflect the generally close physical relationship between the adherent accessory cells and the lymphocytes, although it remains possible that duck monocytes respond to some of the mitogens employed. The data also suggest that LL stimulates a population of cells different to those responding to other mitogens.     

A comparison of the gland of Harder response and head-associated lymphoid tissue (HALT) morphology in chickens and turkeys.

The immunofunctional response of the gland of Harder (GH) was compared in chickens and turkeys using an in vivo assay previously developed for use in chickens. The GH were surgically removed (GHx) from leghorn chicks at 1 day of age and from poults at 2 days of age. Intact birds of each species served as controls. During the fourth week of age, both GH-intact and GHx chicks were exposed to killed Brucella abortus antigen by the ocular or intraperitoneal route. One week later, serum and tears were collected and assayed for antibodies to B. abortus. In addition, all birds were killed at the end of the trial period, and the heads were fixed and processed for histologic examination. Various components of the head-associated lymphoid tissue (HALT) including the GH, nasal glands, lacrimal glands, lacrimal ducts, eyelid conjunctiva, and nasal cavity mucosa/submucosa, were evaluated microscopically using a scoring system to estimate quantity and degree of development of immune tissue in those sites. Results of all analyses indicate that functional response and morphology of the HALT are comparable in turkeys and chickens.