Reproductive efficiency and maternal-offspring transfer of gossypol in rainbow trout (Oncorhynchus mykiss) fed diets containing cottonseed meal.

In a preceding study, complete substitution of fish meal protein with cottonseed meal (CM) protein did not affect the survival or growth rate of adult rainbow trout over a 6-mo period. Gossypol, a naturally occurring compound in cottonseeds, has an antifertility effect in terrestrial animals, but information regarding salmonid fish is lacking. Female rainbow trout in this experiment were fed diets with either 0, 25, 50, 75, or 100% (diets 1 to 5) of the fish meal protein replaced with CM protein until first maturation and spawning to study long-term effects on growth and reproduction. Feeding diets containing CM over a total period of 10 mo did not result in differences in growth and mortality compared to the control group (P > 0.05). Increased CM incorporation levels resulted in decreased (P < 0.05) blood hemoglobin (10.6 +/- 1.3, 8.4 +/- 1.8, 7.3 +/- 1.1, 6.9 +/- 0.8, and 5.6 +/- 1.4 g/dL) and hematocrit (49.6 +/- 3.9, 38.5 +/- 9.3, 34.4 +/- 3.7, 34.8 +/- 4.9 and 28.0 +/- 6.8%) levels in diets 1 to 5, respectively. The CM incorporation level had no effect (P > 0.05) on the number of eggs produced per female but led to a reduction (P < 0.05) in egg weight. Eyed stage survival of embryos was low in all dietary groups and did not show differences (P > 0.05). However, an increasing CM incorporation level led to a linear increase (P < 0.05) in the number of females that produced no viable embryos (23.1, 37.5, 42.9, 60.0, and 71.4%). Gossypol in the diet was absorbed by the female trout and transferred to the eggs (0, 2.2 +/- 0.5, 6.7 +/- 1.6, 10.6 +/- 4.2, and 20.0 +/- 2.6 micrograms/g in diets 1 to 5, respectively). A high concentration of gossypol remained in the juveniles at the swim-up stage (endogenous yolk-absorbed) (0.6 +/- 0.3, 2.4 +/- 0.3, 3.4 +/- 0.0, and 4.7 +/- 1.0 micrograms/g, diets 2 to 5, respectively). The findings suggest that replacement of the dietary fish meal protein with CM protein has no effect on fish growth and mortality but may lead to a reduction in reproductive performance in female rainbow trout.     

The Effect of Exogenous Hormone Treatment on Spermiation in Rhynchocypris oxycephalus (Sauvage and Dabry)

For the evaluation of hormonal control of spermiation in fish, a method to quanify the spermiation response of mature Rhynchocypris oxycephalus (Sauvage and Dabry) to hormonal therapy is described. Spermatocrit was determined after 7 min centrifugation at 18,000 ± g and sperm density was estimated by a standard hemocytomer method. Sperm density can be predicted from spermatocrit since their relationship is linear as described by the regression equation, Y = 3.68X - 27.18 ( R ² = 0.82, N = 50). where Y is spermatocrit and × is sperm density. Milt production by mature R. oxycephalus was highest at 24 h after injection of 1,000 IU human chorionic gonadotropin (HCG) and 50 μg luteinizing hormone-releasing hormone analogue (LHRHa) per kg body weight. Increased milt production coincided with low spermatocrit and sperm density levels. These results demonstrate that spermiation in mature R. oxycephalus can be reliably evaluated by a spermatocrit method and that HCG and LHRHa are effective in stimulating of spermiation in this species.     

Morphological study on the stomach of the lesser mouse deer (Tragulus javanicus) with special reference to the internal surface.

The stomach of the lesser mouse deer (Tragulus javanicus) was observed macroscopically. It consisted of only three compartments, rumen, reticulum and abomasum without omasum. The rumen was S-shaped with large ventral and caudoventral blind sacs and the reticulum was larger than the abomasum. Internally, the rumen was covered with numerous ruminal papillae even on the pillars and the ruminoreticular fold. These papillae were leaf- or tongue-like shaped and varied in size and density. The reticulum had honey-combed crests and the secondary crests were found rarely. The lips of the reticular groove were prominent and more developed in the aboral part than in the oral one. A sac-like transition zone, which had more prominent mucosal folds than had the floor of the reticular groove, was observed between the caudal end of the reticular groove and the abomasum. Mucosal folds of the abomasum were spiral, low but rather thick. These findings were discussed in view of comparison with other ruminants and of possible functional implications.     

A field study on reproductive efficiency of mares maintained predominately on native pasture

A field study utilizing 145 mares of various age and breeding status was conducted to determine reproductive performance under native range conditions with only limited supplemental feeding. All mares had an average initial body condition score of 4.5 and a final score of 5.1 by the time breeding was completed and mares returned to pasture. Average foaling rate was 80%, and mares that had not conceived during the previous breeding season had a foaling rate of 94%, which was higher (P<.05) than 74% for lactating mares. Mares 16 years and older had a significantly lower foaling rate (P<.05) than younger mares. Old mares that were lactating at time of breeding had only a 37% foaling rate, which was less (P<.05) than for young lactating mares. The 94 mares bred by natural cover or artificial insemination that actually foaled required 1.43 cycles per conception. Lactating mares in the oldest age group required more cycles per conception (P<.05) than open mares, and these older, lactating mares also required more cycles per conception than younger mares with foals at side. Those mares diagnosed as pregnant or open at 45 days post breeding had a pregnancy rate of 97%. Average pregnancy loss for all mares was 7.7%. These data indicate that lactating mares in moderate body condition tended to skip a breeding season and that a body condition score of 5 was only marginally acceptable, especially in the case of lactating mares. Authors' address: Equine Science Program, Department of Animal Science, Texas Agricultural Extension Service, Texas A&M University, College Station, TX 77843. Technical Article Number 30023, Texas Agr. Exp. Sta.     

Uroendoscopy. Evaluation of the lower urinary tract.

Recent advances in uroendoscopy have allowed diagnostic evaluation of the lower urinary tract in most of our canine and feline patients. By providing a magnified view of the luminal surfaces of the lower urinary tract, uroendoscopy provides useful diagnostic information that is not readily available even by more invasive techniques.     

Postanesthetic Pulmonary Edema In an Arab Stallion

A six-year-old arabian stallion was admitted to The Ohio State University Veterinary Hospital for evaluation and repair of a comminuted fracture of the second phalanx. The horse developed impaired arterial oxygenation during surgey and pulmonary edema post-operatively. We postulate that impaired arterial oxygenation resulted from atelectasis of the dependent lung during annesthesia, and the pulmonary edema occurred following re-expansion of the atelectatic of the initiating cause of the edema, removal of excess lung water from the alveoli, and restoration of normal arterial oxygenation. The horse was fully recovered within 12 hours of initiation of clinical signs of respiratory compromise. The horse was fully recovered within 12 hours of initiation of clinical signs of respiratory compromise. This report describes re-expansion pulmonary edema due to reperfusion injury in a horse, treatment of the condition, and a possible explanation of the pathogenesis of this pulmonary pathology.     

Effect of Split Nitrogen Application on Growth and Yield of Wheat (T. aestivum L.) Genotypes with Different N-Assimilation Potential

A field experiment was conducted with different nitrogen regimes to assess the growth and yield performance of wheat genotypes which differ in nitrate assimilation potential. Genotypic differences in biomass accumulation were observed at different growth stages. The nitrogen treatment had little effect on biomass accumulation at early stages of growth, while at later stages of growth there was enhanced biomass accumulation when N was applied in more than two splits. On an average, genotypes with high nitrate reductase activity (the 'HNR' genotypes) accumulated 14.2 % more biomass than the genotypes with low nitrate reductase activity ('LNR' genotypes) when an extra dose (40 kg N ha⁻¹) of nitrogen was given at the time of anthesis. The application of nitrogen in more than two splits increased grain yield of both 'HNR' and 'LNR' genotypes mainly by increasing grain weight per ear. The application of an extra dose of nitrogen (40 kg N ha⁻¹) at the time of anthesis increased grain yield of 'HNR' genotypes by 38.5 % as compared to 'LNR' genotypes.