The distribution of ganglion cells in the equine retina and its relationship to skull morphology

It has recently been reported that a strong correlation exists between the distribution of retinal ganglion cells and nose length in the domestic dog. To determine if this phenomenon occurs in another domestic species with diverse skull morphology, the current study examined the distribution of retinal ganglion cells in 30 horses from a variety of breeds. There was a significant variation in the density of ganglion cells found across the retinae. Breed was a significant predictor for ganglion cell density within the visual streak. A strong positive correlation exists between the density of ganglion cells in the visual streak and nasal length. Significant variation was also seen in the area centralis but did not correlate with any of the recorded skull measurements. The findings of this study provide us with further understanding of the equine visual system and the level of variation that exists between individuals of the same species.     

The effect of levels of concentrate in feedlot diets on the health status of beef calves

In this two year study we investigated the effect that the level of concentrate in feedlot diet had on the occurrence of health problems in bull calves belonging to two multibreed groups.

In each of the two years, the 168 day feedlot period was divided into two equal periods of 77 days with an intervening 14 day adjustment period. During the first period, the animals in half of the pens within each breed-group received a high concentrate (85% grain) diet (H) while the rest of the pens received a diet (L) of hay ad libitum and half as much concentrate as the bulls on high concentrate. The L diet contained an average of 48% grain. In the second period, diets of bulls in half of the pens within each breed-group were switched from L to H and vice versa. During the feedlot period, the incidence of sickness among bulls was recorded. Disease incidence was higher in the second year compared to the first. In the second year, 49 out of 56 (87.5%) calves on the high concentrate diet required treatment for respiratory infections compared to only four (7.14%) in bulls on the low concentrate diet. The results suggest that a high concentrate diet for animals in feedlots may be more stressful to calves coming directly to the feedlot following weaning compared to a low concentrate diet, thereby acting as an additional predisposing factor to respiratory infections.

     

Epidemiology of poultry parasitic disease in village breeding in Niamey area, Niger]

An inventory of poultry parasitism in hens and Guinea fowls in village breeding was conducted from May 1985 to April 1987 in the Niamey department. About 1,200 post-mortem examinations and haematological tests, as well as 6,000 faecal egg counts were performed. The internal polyparasitism was observed in two thirds of the cases. Guinea fowls were more infected than chickens. Cestodiasis was frequent in both species. The omnipresent spirochaetosis made a potential danger for the improved flocks. Ectoparasitoses were mainly represented by argas and scaly-legs, which affected one chicken out of ten.     

Influence of trenbolone acetate combined with estradiol-17 beta on growth performance, body characteristics, and chemical composition of goat kids fed milk and slaughtered at different ages.

The effects of anabolic agents (5 mg of estradiol-17 beta + 30 mg of trenbolone acetate) on body characteristics and chemical composition of gain were studied in 58 intact male goat kids fed milk replacer. Four kids were slaughtered at 7 d of age to constitute the initial group. The other kids were allotted in a 2 x 3 factorial arrangement with slaughter age (41, 49, and 56 d of age) and treatment (control and implanted at 21 d old) as factors. Energy intake decreased during the first 4 wk after treatment; implanted kids had the same ADG as controls but a better energy efficiency (P < .05). During the last week of the trial, energy intake was the same; treated kids tended (P < .10) to have a higher empty body gain (EBG). Anabolic agents increased carcass (P < .10) and hide proportions (P < .01) in empty BW and in EBG for all groups (except for carcass at 56 d old). Anabolic agents reduced the contribution of adipose tissues (P < .05), empty digestive tract (P < .05), and other organs (P < .01) to EBG. At all slaughter ages, the chemical composition of carcass and hide wet tissues, all dissectible adipose tissues, and EBG were altered by treatment. In these tissues (except for mesenteric fat tissue), water content increased and lipid content decreased (P < .05), but these effects diminished with age. Expressed on a DM basis, the CP content of the treated carcasses was increased in all groups (P < .05). Implanting high doses of steroids altered nutrient partitioning, which reduced fat and increased water and protein in the body.     

Respiratory muscle perfusion in ponies during prolonged submaximal exercise in thermoneutral environment.

Distribution of blood flow among various respiratory muscles was examined in 8 healthy ponies during submaximal exercise lasting 30 minutes, using radionuclide labeled 15-microns diameter microspheres injected into the left ventricle. From the resting values (40 +/- 2 beats/min; 37.3 +/- 0.2 C), heart rate and pulmonary arterial blood temperature increased significantly at 5 (152 +/- 8 beats/min; 38.6 +/- 0.2 C), 15 (169 +/- 6 beats/min; 39.8 +/- 0.2 C), and 26 (186 +/- 8 beats/min; 40.8 +/- 0.2 C) minutes of exertion, and the ponies sweated profusely. Mean aortic pressure also increased progressively as exercise duration increased. Blood flow increased significantly with exercise in all respiratory muscles. Among inspiratory muscles, perfusion was greatest in the diaphragm and ventral serratus, compared with external intercostal, dorsal serratus, and scalenus muscles. Among expiratory muscles, blood flow in the internal abdominal oblique muscle was greatest, followed by that in internal intercostal and transverse thoracic muscles, in which the flow values remained similar. The remaining 3 abdominal muscles had similar blood flow, but these values were less than that in the internal intercostal, transverse thoracic, and internal abdominal oblique muscles. Blood flow values for all inspiratory and expiratory muscles remained similar for the 5 and 15 minutes of exertion. However, at 26 minutes, blood flow had increased further in the diaphragm, external intercostal, internal intercostal, transverse thoracic, and the external abdominal oblique muscle as vascular resistance decreased. On the basis of our findings, all respiratory muscles were activated during submaximal exercise and their perfusion had marked heterogeneity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Michel's medium as a preservative for immunofluorescent staining of cutaneous biopsy specimens in dogs and cats

Paired 3-mm skin biopsy specimens from 24 dogs and 11 cats with suspected autoimmune dermatopathies were stained with fluorescein-conjugated antisera. In each case, 1 specimen was immediately embedded in optimum cutting temperature compound, quick frozen to -30 C, processed, stained, and examined. The other sample was placed in Michel's transport medium, held for 7 days, and then processed, stained, and examined. The location, quality, and intensity of immunofluorescent staining (when positive) were then compared in the 2 specimens. There were no differences in the staining patterns between the specimens processed immediately and those held in Michel's medium, thus demonstrating the validity of preserving canine and feline skin biopsy specimens in Michel's medium for immunofluorescent examination.     

Propylthiouracil-associated hemolytic anemia, thrombocytopenia, and antinuclear antibodies in cats with hyperthyroidism

Nine of 105 cats with hyperthyroidism treated with propylthiouracil developed a serious immune-mediated drug reaction during treatment. Adverse clinical signs, which developed after 19 to 37 days (mean, 24.8 days) of propylthiouracil administration, included lethargy, weakness, anorexia, and bleeding diathesis. Physical examination revealed pale mucous membranes, and petechial hemorrhages of the skin and oral cavity. Results of hematologic testing revealed severe anemia and thrombocytopenia. The direct antiglobulin (Coombs') test was positive in all 7 cats evaluated, whereas the serum antinuclear antibody titer was greater than or equal to 1:10 in 5 of the 8 cats tested. In 4 of the cats, treatment included appropriate supportive therapy and cessation of propylthiouracil; in these cats, anemia and thrombocytopenia resolved and Coombs' and antinuclear antibody tests became negative within 2 weeks.     

Effect of Tomanol on the pharmacokinetics and tissue distribution of penicillin G in dairy cows

Following concomitant intravenous administration of Tomanol and sodium penicillin G to six Dutch Friesian dairy cows a significant decrease in total body clearance of penicillin (34.7%) and a prolongation of the elimination half-life of penicillin (17.2%) was observed. Tomanol did not affect other pharmacokinetic parameters such as rate constants of drug transfer (k12/k21, alpha en beta), distribution volume of the central compartment (V1), and extrapolated serum drug levels. Intravenous or intramuscular administration of Tomanol had no effect on the tissue distribution of penicillin G, because neither a change in the ratios of muscle to serum and of kidney cortex to serum nor a change in an induced steady state level of low penicilline G serum concentrations was observed. From the data obtained it is concluded that concomitant Tomanol administration with penicillin induces an elevation of the serum penicillin concentration and prolongs the persistence of penicillin residues in carcass meat and organs.     

Une néphrose toxique chez des veaux traités par un médicament contenant des produits de dégradation des tétracyclines

A toxic nephrosis in calves treated with a drug containing tetracycline degradation products