Artificial Insemination with Frozen Semen in Ewes at Different Times of the Breeding Season

Totally 13575 ewes of two different breeds, Dala and Spel, were inseminated with semen, frozen in straws and thawed at 70°C for 8 sec. An insemination dose of 0.2 ml containing approx. 150 × 10⁶ spermatozoa with at least 45 to 50% progressive motility was imerted 5 to 12 mm into the cervix. The insemination was performed once between 12 and 30 h after the onset of heat. The NR rate of the Dala ewes increased significantly during the season. The NR rate of the ewes inseminated before 15. November was 44.3%, from 15. to 20. November 52.2%. from 20. to 25. November 55.3% and from 25. November and later 61.4%. The corresponding values for the ewes of the Spel breed were 57.3, 58.7, 61.5 and 71.0% respectively, and only the difference between the two last values was statistically significant. The difference between the fertility of the two breeds was significant within each of the periods .     

Acute infection of encephalomyocarditis (EMC) virus in Syrian hamsters.

One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters.     

Free-running rhythms of adrenocorticotropic hormone (ACTH), cortisol and melatonin in pigs.

In the domestic pig, a circadian rhythm of plasma cortisol occurs, with greatest concentrations in the morning and lowest concentrations in the afternoon. However, photic entrainment of the rhythms of ACTH and melatonin in pigs have not been defined clearly. This experiment was designed to evaluate free-running rhythms of ACTH, cortisol and melatonin in pigs housed in constant light (LL) and constant darkness (DD). Twelve crossbred barrows, maintained under ambient photoperiod, were catheterized and tethered individually in two environmentally controlled rooms, one with LL and the other with DD. For animals in LL, fluorescent lights provided 202 +/- 15 (mean +/- standard deviation) lux of light at 65 cm above the floors. Incandescent nightlights equipped with 7 watt red bulbs provided 7 +/- 2 lux and were illuminated continuously in both rooms. Pigs were given at least 14 d exposure to LL and DD, then samples of plasma and serum were obtained at hourly intervals for 48 hr. Plasma was assayed for ACTH, and serum for cortisol and melatonin. Periodograms were constructed to analyze the data. For this type of analysis, a statistic, Qp, is calculated, and circadian periodicity is suggested if maximum Qp (Qp max) occurs at or near 24 hr. The period of the free-running rhythms (tau) at Qp max for ACTH, cortisol and melatonin for pigs in LL (23.80 +/- .01, 23.78 +/- .01, and 23.21 +/- .02 hr, respectively) did not differ significantly from those for pigs in DD (23.39 +/- .01, 23.20 +/- .01, and 22.55 +/- .02 hr, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Utilization of free and protein-bound lysine in the Japanese quail

The utilization of dietary lysine for protein synthesis is affected by the digestibility of protein-bound lysine, by its intestinal resorption and by its oxidative catabolism. The approach chosen in this paper enables a comparison of the cumulative effect of these processes on the utilization of free and protein-bound lysine, respectively. The principle of the approach is based on a quantification of the expiration of 14C-labelled carbon dioxide after an oral administration of a diet, which contains L-(U-14C)-lysine either as a free amino acid or bound to yeast proteins. During an adaptation phase cockerels of the Japanese quail received a diet based mainly on ground wheat and wheat gluten. This diet was supplemented either with yeast proteins or with a mixture of L-amino acids which simulates the composition of the yeast proteins. In the main experiment the expiration of labelled carbon dioxide was measured during 240 minutes after the administration of the corresponding labelled diets. Just before treatment the animals were either in the postprandial phase or in a state of slight hunger. The maximum of expiration of labelled carbon dioxide occurred around the 60th minute after administration of the corresponding labelled diets. The cumulative expiration of labelled carbon dioxide, expressed in per cent of the radioactive dose used, amounts to 15.5% and 14.3% for free and protein-bound lysine, respectively. The utilization of both forms of lysine in the Japanese quail is lower than in broilers.     

Fertilizing capacity of the ejaculate of nutria (Myocastor coypus) after the removal of the seminal vesicles as evaluated by the penetration test and natural mating

The fertility of male coypu sperm following seminal vesicle extirpation was investigated using the penetration test into the egg of Syrian golden hamster (Mesocricetus auratus). Ejaculates were obtained from five males by means of electro-ejaculation under halothane narcosis. The results of the zona-free hamster eggs (ZFHE) penetration test showed that the ejaculates of all the surgically treated coypu males were fertile and that ZFHE value fluctuated from 54 to 76.6%. The results obtained in experiments with natural mating revealed that the extirpation of male coypu seminal vesicles did not affect their fertility. In total 47 foetuses were found post mortem in ten coypu females covered by surgically treated males, which on average represented 4.7 foetuses per female.     

Practice relevant rapid tests for milk progesterone in cattle compared with a laboratory-connected routine method

Four commercially available semiquantitative milk progesterone tests (Ovucheck-Praxistest: Cambridge Veterinary Science/Smith Kline), Progestassay-Milchprogesteron (Pitman-Moore/Janssen), Reprostrip-Progesteron-Schnelltest (Noctech/Albrecht), Enzygnost-Milchprogesteron (IQ, 'Bio' UK/Hoechst Veterin?r) were examined for their accuracy by using them for the determination of progesterone levels of 64 milk samples, i.e. 1556 single assays. Several test series were performed, using codified samples and changing sequences. Three or four test persons respectively, performed the tests independently and classified the samples semiquantitatively. These test results were then compared to the results acquired by measuring the progesterone levels of the same samples by means of an approved quantitative, labor-bound progesterone test (Hormonost: Biolab). These control tests were performed at a specialized routine labor, by different personnel and at a different location. Lastly, in 48 out of the 64 sampled animals the reproductive status could be evaluated clinically and was taken into account as well. Samples yielding high progesterone levels, i.e. greater than or equal to 9 ng/ml were classified correctly in 84.4 to 96.5% of the cases, whereas samples with low levels (less than or equal to 2.5 ng/ml) were classified correctly in 68.8 to 90.0% of the cases only. Samples ranging between this spectrum (greater than 2.5 less than 9 ng/ml) were classified correctly only in 42.1 to 52.6% of the cases. However, this range appears to be of the most interest for the veterinary practitioner since cows in proestrus or early interestrus tend to have mild progesterone levels within these values. On the other hand, clinical findings are often insufficient for a proper diagnosis just in these animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of nemadectin, a new broad-spectrum endectocide, against natural infections of canine gastrointestinal helminths

Nemadectin, a new broad-spectrum endectocide, was highly efficacious against natural infections of all the major canine gastrointestinal helminths. At single oral dosages of 0.2-0.4 mg kg-1 body weight (BW), a liquid formulation administered in gelatin capsules was 100% effective in eliminating natural infections of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Uncinaria stenocephala. Tablets (267 mg) containing 4.6% nemadectin given at a rate of 1/3 tablet per 20 kg BW (0.2 mg nemadectin kg-1) were 100% active against T. canis, A. caninum and U. stenocephala. With both formulations, an increase in the dose rate to 0.6-0.8 mg kg-1 BW resulted in 99-100% elimination of Trichuris vulpis infections. No adverse reactions were observed in any of the treated dogs.