Endocrine and ovarian changes in response to the ram effect in medroxyprogesterone acetate-primed Corriedale ewes during the breeding and nonbreeding season

Two experiments were performed to determine the endocrine and ovarian changes in medroxyprogesterone acetate (MAP)-primed ewes after ram introduction. Experiment 1 was performed during the mid-breeding season with 71 ewes primed with an intravaginal MAP sponge for 12 days. While the control (C) ewes (n = 35) were in permanent contact with rams, the ram effect (RE) ewes (n = 36) were isolated for 34 days prior to contact with rams. At sponge withdrawal, all ewes were joined with eight sexually experienced marking Corriedale rams and estrus was recorded over the next 4 days. The ovaries were observed by laparoscopy 4-6 days after estrus. Four weeks later, pregnancy was determined by transrectal ultrasonography. In eight ewes from each group, ovaries were ultrasonographically scanned; FSH, LH, and estradiol-17beta were measured every 12 hours until ovulation or 96 hours after estrus. The response to the rams was not affected by the fact that ewes had been kept or not in close contact with males before teasing. No differences were found in FSH, LH, estradiol-17beta concentrations, growth of the ovulatory follicle, onset of estrus, ovulation rate, or pregnancy rate. Experiment 2 was performed with 14 ewes during the nonbreeding season. Ewes were isolated from rams for 1 month, and received a 6-day MAP priming. Ovaries were ultrasonographically scanned every 12 hours, and FSH, LH, estradiol-17beta, and progesterone were measured. Ewes that ovulated and came into estrus had higher FSH and estradiol-17beta levels before introduction of the rams than did ewes that had a silent ovulation. The endocrine pattern of the induced follicular phase of ewes that came into estrus was more similar to a normal follicular phase, than in ewes that had a silent ovulation. The follicle that finally ovulated tended to emerge earlier and in a more synchronized fashion in those ewes that did come into estrus. All ewes that ovulated had an LH surge and reached higher maximum FSH levels than ewes that did not ovulate, none of which had an LH surge. We conclude that (a) the effect of ram introduction in cyclic ewes treated with MAP may vary depending on the time of the breeding season at which teasing is performed; (b) patterns of FSH, and estradiol-17beta concentrations, as indicators of activity of the reproductive axis, may be used to classify depth of anestrus; and (c) the endocrine pattern of the induced follicular phase, which is related to the depth of anestrus, may be reflected in the behavioral responses to MAP priming and the ram effect.     

Nephrotic syndrome: a platelet hyperaggregability state

Nephrotic syndrome characterized by hypoalbuminemia and hyperlipidemia is associated with an increased incidence of thromboembolism and increased platelet hyperaggregability. Although plasma coagulation proteins are also abnormal, changes are too inconsistent to attribute thromboembolic complications to the coagulation cascade alone. Antithrombin III (ATIII) has been shown to be deficient in nephrotic syndrome. There is, however, an increase in alpha 2 macroglobulin. It is clear that platelet to platelet interactions require exposure of platelet fibrinogen receptors, the binding of fibrinogen to these receptors, platelet crossbridging, and subsequent platelet aggregation. Fibrinogen is consistently elevated in nephrotic syndrome. Hyperlipidemia and hypoalbuminemia in nephrotic syndrome increases the availability of thromboxane A2 (TxA2) by increasing the availability of TxA2 precursors and the removal of TxA2 inhibitors. Thromboxane A2 is a known inducer of platelet aggregation probably through the exposure of platelet fibrinogen receptors. Recently, fibronectins a group of adhesive proteins, were implicated in platelet to platelet interactions. Since thrombin increases the expression of platelet surface fibronectin, fibronectin may be involved in thrombus formation in nephrotic syndrome. Thromboembolic formation in nephrotic syndrome is a composite mechanism involving the coagulation cascade, platelet-platelet interactions, and platelet-surface interactions.     

Suppressor activity of bovine Fc gamma positive cells during a persistent infection with Mycobacterium avium

The cell mediated immune response (CMI) was measured in calves after experimental infection with Mycobacterium avium. Using the tuberculin skin test a CMI response could be measured from four to 14 weeks after infection, and with a lymphocyte stimulation (LS) test from six to 40 weeks. One year after infection no CMI response was detected by either of the tests, in spite of the fact that in such calves M avium bacteria could be found in the intestinal lymph nodes at autopsy. After removal of mononuclear cells bearing receptors for the Fc part of IgG, the peripheral blood lymphocytes obtained from a calf infected one year earlier responded to M avium pure protein derivative in the LS test in contrast to lymphocytes obtained from uninfected calves.     

Toxicological effects of gamma-irradiated sewage solids fed as seven percent of diet to sheep for four years

Breeding ewes in drylot were fed pelleted complete diets with 3% cottonseed meal (CSM) or 7% dried, gamma-irradiated sewage solids (DGSS) for 4 yr. Cytochrome P-450 (P-450) content and enzyme activities for xenobiotics biotransformations were assayed in livers after 2 yr and in livers, kidneys and ileal tissue after 4 yr. Dietary DGSS caused no increase in P-450 and few changes in activities of oxidative, hydrolative and conjugative biotransformational enzymes. Consumption of DGSS for 4 yr caused slight enlargement of spleens (1.1-fold, P less than .10) and ovaries (1.3-fold, P less than .10), but no change in size of livers, kidneys, hearts, adrenals and thyroids (P greater than .10), nor liver vitamin A levels (P greater than .10). Of 22 refractory lipophilic residues assayed in abdominal adipose tissue, few were detected and of those detected DGSS caused none to exceed normal levels. Dietary DGSS increased (P less than .01) Fe in livers 1.5-fold and in spleens 5.6-fold, and increased Cu in livers 1.3-fold (P less than .01) and in kidneys 1.2-fold (P less than .05). Dietary DGSS increased Cd levels in livers (P less than .01) but not in kidneys or spleens (P greater than .10); yet all Cd levels were within ranges for livestock fed conventional feed. Dietary DGSS caused no increase (P greater than .10) in levels of Ag, Ca, Cr, Hg, K, Mg, Mn, Na, Ni, P, Pb or Zn in livers, kidneys or spleens. There were no histopathological lesions of toxicosis except mild hemosiderosis of spleens. Consumption of a diet with 7% DGSS throughout 4 yr caused no hazardous accumulation of toxic elements and little, if any, evidence of toxicosis.