Testosterone concentration in the male chick brain: an autoradiographic survey

Differential uptake of [(3)H]testosterone in male chick brain was found in periventricular areas of preoptic-hypothalamic continuum. Concentration of silver grains for all decapitation periods was especially high in the medial preoptic area, particularly the nucleus praeopticus paraventricularis magnocellularis. Distribution of testosterone-sensitive cells is in agreement with studies showing neuroanatomical control of reproductive behavior by the avian forebrain.     

Effects of dietary zinc and iron supplementation on mineral excretion, body composition, and mineral status of nursery pigs

Two experiments were conducted to evaluate the effects of dietary Zn and Fe supplementation on mineral excretion, body composition, and mineral status of nursery pigs. In Exp. 1 (n = 24; 6.5 kg; 16 to 20 d of age) and 2 (n = 24; 7.2 kg; 19 to 21 d of age), littermate crossbred barrows were weaned and allotted randomly by BW, within litter, to dietary treatments and housed individually in stainless steel pens. In Exp. 1, Phases 1 (d 0 to 7) and 2 (d 7 to 14) diets (as-fed basis) were: 1) NC (negative control, no added Zn source); 2) ZnO (NC + 2,000 mg/kg as Zn oxide); and 3) ZnM (NC + 2,000 mg/kg as Zn Met). In Exp. 2, diets for each phase (Phase 1 = d 0 to 7; Phase 2 = d 7 to 21; Phase 3 = d 21 to 35) were the basal diet supplemented with 0, 25, 50, 100, and 150 mg/kg Fe (as-fed basis) as ferrous sulfate. Orts, feces, and urine were collected daily in Exp. 1; whereas pigs had a 4-d adjustment period followed by a 3-d total collection period (Period 1 = d 5 to 7; Period 2 = d 12 to 14; Period 3 = d 26 to 28) during each phase in Exp. 2. Blood samples were obtained from pigs on d 0, 7, and 14 in Exp. 1 and d 0, 7, 21, and 35 in Exp. 2 to determine hemoglobin (Hb), hematocrit (Hct), and plasma Cu, (PCu), Fe (PFe), and Zn (PZn). Pigs in Exp. 1 were killed at d 14 (mean BW = 8.7 kg) to determine whole-body, liver, and kidney mineral concentrations. There were no differences in growth performance in Exp. 1 or 2. In Exp. 1, pigs fed ZnO or ZnM diets had greater (P < 0.001) dietary Zn intake during the 14-d study and greater fecal Zn excretion during Phase 2 compared with pigs fed the NC diet. Pigs fed 2,000 mg/kg, regardless of Zn source, had greater (P < 0.010) PZn on d 7 and 14 than pigs fed the NC diet. Whole-body Zn, liver Fe and Zn, and kidney Cu concentrations were greater (P < 0.010), whereas kidney Fe and Zn concentrations were less (P < 0.010) in pigs fed pharmacological Zn diets than pigs fed the NC diet. In Exp. 2, dietary Fe supplementation tended to increase (linear, P = 0.075) dietary DMI, resulting in a linear increase (P < 0.050) in dietary Fe, Cu, Mg, Mn, P, and Zn intake. Subsequently, a linear increase (P < 0.010) in fecal Fe and Zn excretion was observed. Increasing dietary Fe resulted in a linear increase in Hb, Hct, and PFe on d 21 (P < 0.050) and 35 (P < 0.010). Results suggest that dietary Zn or Fe additions increase mineral status of nursery pigs. Once tissue mineral stores are loaded, dietary minerals in excess of the body's requirement are excreted.     

Effect of acrosomal defects on fertility of bulls used in artificial insemination and natural breeding

Four bulls that produced spermatozoa with a high percentage of abnormal acrosomes were individually placed in pens with females for 21 days. Frozen semen from 2 of the bulls was used for artificial insemination. One of the bulls was placed in a competitive mating situation with normal bulls at pasture. First service pregnancy rates were determined by transrectal ultrasonography 28 days after bull removal from breeding pens, or after the last artificial insemination. The results of competitive mating at pasture were determined from breeding observations, the phenotypic characteristics of calves sired, and blood typing for parentage. The results of these studies suggest that bulls that produce a high percentage of spermatozoa with indented acrosomes may have normal fertility when used in artificial insemination or in single sire mating; however, their fertility may be low when breeding competitively with bulls with normal spermiograms.     

Isolation of Neospora caninum from the brain of a naturally infected dog, and production of encysted bradyzoites in gerbils

Neospora caninum was isolated from the brain of an adult dog in Brazil. Cerebral tissue from the dog was inoculated into Mongolian gerbils. Gerbils were euthanized 3-4 months later and bradyzoite-containing tissue cysts were observed in their brains. N. caninum (designated NC-Bahia) was isolated in cell culture after inoculation with tissue cysts from the gerbils. The identity of the parasite was confirmed by immunohistochemical examination and polymerase chain reaction (PCR). Gerbils may be a useful alternative to immunosuppressed mice for isolation of N. caninum and for production of encysted bradyzoites.     

Effects of intravenous lidocaine overdose on cardiac electrical activity and blood pressure in the horse

This study aimed to identify blood serum lidocaine concentrations in the horse which resulted in clinical signs of intoxication, and to document the effects of toxic levels on the cardiovascular and cardiopulmonary systems. Nineteen clinically normal mature horses of mixed breed, age and sex were observed. Lidocaine administration was initiated in each subject with an i.v. loading dose of 1.5 mg/kg bwt and followed by continuous infusion of 0.3 mg/kg bwt/min until clinical signs of intoxication were observed. Intoxication was defined as the development of skeletal muscle tremors. Prior to administration of lidocaine, blood samples for lidocaine analysis, heart rate, mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, respiratory rate and electrocardiographic (ECG) data were collected. After recording baseline data, repeat data were collected at 5 min intervals until signs of intoxication were observed. The range of serum lidocaine concentrations at which the clinical signs of intoxication were observed was 1.85-4.53 microg/ml (mean +/- s.d. 3.24 +/- 0.74 microg/ml). Statistically significant changes in P wave duration, P-R interval, R-R interval and Q-T interval were observed in comparison to control values, as a result of lidocaine administration. These changes in ECG values did not fall outside published normal values and were not clinically significant. Heart rate, blood pressures and respiratory rates were unchanged from control values. This study establishes toxic serum lidocaine levels in the horse, and demonstrates that there were no clinically significant cardiovascular effects with serum lidocaine concentrations less than those required to produce signs of toxicity.     

Reproductive response of ewes to immunization with Fecundin (ovandrotone)

Ewes of five crossbred genotypes (total of 221 ewes) were immunized with a commercial preparation of androstenedione-7HSA in DEAE dextran adjuvant in a 2-yr trial. In yr 1 ewes were allocated within genotype to a 2 x 2 application of immunization and premating flushing. In yr 2 they were allocated within previous Fecundin treatment into either Fecundin-treated or control groups. First-time immunization with Fecundin increased ovulation rate by .70 ova/ewe in yr 1 and by .85 ova/ewe in yr 2 (P less than .05). Ewes treated in both years produced fewer ova than those treated in the 2nd yr only (P less than .05), but they did not differ in litter size. Although Fecundin reduced conception to first mating, the overall conception rate was not affected. Litter size of treated ewes was increased by .19 and .38 lambs/ewe lambing (P less than .05) in yr 1 and yr 2, respectively. Fecundin treatment in yr 1 produced a carry-over effect in yr 2 by increasing litter size by .26 lamb/ewe (P less than .05) while reducing conception to first mating. The litter size of ewes with two ovulations was reduced by Fecundin treatment in yr 1 (P less than .05) but showed no consistent pattern in yr 2. Overall, ewes with two ovulations produced .7 to .8 more lambs than ewes with one ovulation, and ewes with three ovulations produced .4 more lambs than those with two ovulations. Ewes of different genotypes did not differ in their response to Fecundin.     

Effect of otic medications containing glucocorticoids on liver function test results in healthy dogs

Otic medications containing triamcinolone or dexamethasone were administered twice daily for 21 days to 2 groups of 4 healthy dogs each. Serum alkaline phosphatase, gamma-glutamyltransferase, alanine transaminase, and aspartate transaminase activities, and serum bile acid and lipoprotein-X concentrations were assayed for 35 days. Increased serum activities for gamma-glutamyltransferase, alkaline phosphatase, and alanine transaminase were detected by day 7 and peaked at day 21. Increases were greater in dogs given the dexamethasone-containing medication. Enzyme activity returned to baseline by day 35. Serum aspartate transaminase activity and bile acid and lipoprotein-X concentrations did not increase.