Staphylococcus-associated abortions in ewes with long-term central venous catheterization.

Forty-two ewes had an intravenous catheter sewn in place in a prepared area over the jugular vein and beginning at 60 days of gestation received an infusion 3 times daily. The infusion consisted of sterile saline or sterile saline containing arginine. Twenty-six ewes in both control and treatment groups aborted between 81 days of gestation and term. Fetuses from 16 ewes that aborted were examined. Most were autolyzed or had early mummification. Macroscopic placentitis and noncollapsing lungs were noted. Large numbers of coagulase-positive Staphylococcus were isolated from fetal abomasal content, lungs, brains, or placentas. Histologically, suppurative placentitis with necrosis and pulmonary aspiration of meconium and amniotic debris often with suppurative bronchopneumonia were observed in abortuses. Four ewes euthanized and examined after abortion had suppurative endometritis. Three ewes had severe, chronic, jugular thrombophlebitis from which coagulase-positive Staphylococcus was isolated. The fourth ewe had mild phlebitis, and Staphylococcus aureus was isolated from both the catheter and the blood. Catheter-associated staphylococcal abortion was diagnosed.

Testosterone immunization blocks the ovulatory process in laying hens without affecting ovarian follicular development.

The role of testosterone in the ovulatory process in hens has been largely neglected. The aim of the present study was to evaluate if testosterone plays an important role on the ovulatory process in laying hens. The effect of active and passive immunization against testosterone on ovarian follicular development and oviposition was studied. Egg laying percentage was evaluated in hens actively immunized against testosterone-BSA (T-AI; n = 6) or BSA (BSA-AI; n = 6). Oviposition was reduced as antibody titer increased in T-AI hens (r = -0.67; P < 0.01). Ovarian structures were assessed in three animals from each group. Follicles reached preovulatory size in both groups, nonetheless, in T-AI hens follicles at different stages of regression indicated that ovulation was blocked by treatment. In the remaining animals, preovulatory concentrations of progesterone and testosterone were determined. A preovulatory surge release of progesterone, preceded by a testosterone peak, was observed in the BSA-AI group (P < 0.05). In contrast, progesterone in T-AI animals remained at basal concentrations. Whereas, testosterone concentrations were significantly greater in T-AI as compared with BSA-AI animals (P < 0.05). Finally, to study the effect of passive immunization on oviposition, hens were passively immunized (PI) on four occasions, on alternate days with anti-T serum (T-PI; n = 10) or anti-BSA serum (BSA-PI; n = 8). During the 13-day period that preceded treatment, oviposition averaged 94.1%. Forty-eight hours after the first immunization, no egg was laid by 8 out of the 10 T-PI hens. During the 10 days following the first passive immunization, there was a reduction in the laying percentage that was significantly greater in T-PI hens (reduction of 52% in T-PI versus 29% in P-BSA, P < 0.01). In summary, these studies show that testosterone immunization hampers egg-laying without affecting ovarian follicular development, suggesting that testosterone has an important role in the ovulatory process in laying hens.

The influence of the corpus luteum on ovarian follicular dynamics during estrous synchronization in goats.

Ovarian follicular dynamics and fertility are unaffected by the presence or absence of a corpus luteum during synchronization of estrus with progestins in goats. On day 5 of the estrous cycle (estrus= day 0), a gestagen-containing sponge was inserted in the vagina for 11 days. To remove corpora lutea, one group of goats (CL-, n=41) received 7.5 mg of luprostiol on days 7 and 8 of the estrous cycle. The second group of goats retained the CL (CL+, n=38). Growth and development of follicles > or =4 mm in diameter were measured daily from onset of estrus to 2 days after subsequent ovulation in seven goats from each group, using rectal ultrasonography. Estrus was detected by the use of a reproductively sterilized buck and estrous does were subsequently mated. The number of waves of follicular development (CL- =3.57+/-0.2 versus CL+ =3.14+/-0.14; P>0.05) did not differ between groups. The second wave of follicular development was present at the time of progesterone decline in the CL- group and neither its duration (CL- =4.8+/-0.4 versus CL+=5.6+/-0.7 days; P>0.05) nor the day of commencement of the third wave of follicular development (CL -=11.6+/-0.7 versus CL+=11.8+/-0.6; P>0.05) were altered by the concentration of endogenous progesterone. The pregnancy rate was similar between the two groups. (CL-=68.29% versus CL+=65.79%; P>0.05). Thus, in goats, ovarian follicular dynamics and fertility were not altered by the presence or absence of a corpus luteum during estrous synchronization.