Aspects of bacteriology and endocrinology of cows with pyometra and retained fetal membranes

In an effort to clarify the pathogenesis of pyometra, 20 cows with retained fetal membranes and 20 without, but with contemporary calving dates were studied. They were palpated and their uteri were subjected to sample collections for bacteriologic cultural examinations twice weekly for 4 weeks. Blood samples were obtained each day and evaluated for serum progesterone concentration. Three cows without and 3 with retained fetal membranes developed pyometra during the study, resulting in 3 groups designated control (CON), cows with retained fetal membranes (RFM), and cows with pyometra (PYO). Bacterial isolations occurred less frequently in the CON group than in the PYO and RFM groups. Growth patterns of bacteria also varied between groups. Coliform and incidental bacteria disappeared from the uterus of the PYO group by the end of the 3rd week. In contrast, heavy growth of Corynebacterium pyogenes and gram-negative anaerobic bacteria developed during this same period in the PYO group. In cows with pyometra, the significant persistent pathogenic bacteria recovered were C pyogenes and gram-negative anaerobic bacteria, especially Fusobacterium necrophorum and Bacteroides melaninogenicus. Anaerobic bacteria were isolated simultaneously with C pyogenes in most cows of the PYO group, but less often in CON and RFM groups, and highest growth levels were present near the time of ovulation. Clinically, pyometra usually developed about 10 days after observation of concurrent ovulation and high growth levels of C pyogenes and gram-negative anaerobic bacteria. A hypothesis is presented for development of pyometra in the cow.     

Cervical vertebral interbody fusion in the horse: a comparative study of bovine xenografts and autografts supported by stainless steel baskets

A modified form of the Cloward technique for anterior cervical fusion in human beings was used in the application of different grafts for evaluation of their effectiveness in stabilizing equine cervical vertebrae. Results of bovine xenograft implants in 8 horses were compared with results of stainless steel baskets (SSB) packed with cancellous autogenous bone in 8 horses. Graft material was incorporated in all cases. Evidence of graft rejection was not present. Both forms of implants decreased the mobility of the intervertebral space in which they were implanted. A fibrous connective tissue union was prevalent after xenograft implantation. Osseous union was prevalent after implantation of the SSB. Reduction in range of motion was greatest at those sites with the SSB.     

An evaluation of bias in estimated breeding values for weaning weight in Angus beef cattle field records. II. Estimates of bias due to genetic trend

Field records (53,989) from the American Angus Association were used to evaluate the impact of bias associated with genetic trend in estimated breeding values for weaning weight. Annual estimates of breeding values were calculated using the reported weaning weight ratios and ratios adjusted for estimated genetic trend. Genetic gains were assumed to be consistently linear. Bias was estimated as the difference between the two estimates, and herd averages across years for dam's bias ranged from .38 to 3.86 ratio units. The bias was a function of the magnitude of the estimated trend and the generation interval. The impact of this bias was small in young cows, but increased rapidly after diet fourth or fifth calves. When annual genetic trend was less than .75 ratio units, the loss in selection response (based upon selecting the top 10 and 50% of males and females, respectively) did not exceed 2.5%. In herds with trends between .75 and 1.1 units/yr, the loss was 6 to 8%. In the five herds where estimated trend exceeded 1.1 units/yr, the loss ranged from 10.8 to 25.2%).     

Teratological examination of the insecticide methylparathion (Wofatox 50 EC) on pheasant embryos. 1. Morphological study

Teratogenic effects of methylparathion / Wofatox 50 EC/ and Parathion 20 WP as positive control material were tested in pheasant embryos. On the 12th day of incubation 0.1 ml of the emulsions or suspensions of the insecticides at different concentrations was inoculated into the air space of embryonated eggs. The following dose levels were employed: 27 and 270 mg/kg egg of Wofatox 50 EC, and 10 mg/kg of Parathion 20 WP. Morphological changes were evaluated by macroscopic, skeletal staining and light microscopic examinations of the embryos. Primary hypoplasia or atrophy developed in the cervical musculature /m. longus colli/ accompanied by lordosis and scoliosis of the cervical spine. In most cases we also found cyllosis .     

Trials of an inactivated equid herpesvirus 1 vaccine: challenge with a subtype 1 virus

Vaccinated yearlings , two-year-old and in-foal pony mares with appropriate controls were exposed to aerosols of a subtype 1 virus one to two months after two or three vaccinations; all became infected. No obvious differences in the febrile responses, clinical signs and subsequent abortions were found between vaccinated and control mares. All vaccinated yearlings and two-year-old ponies developed a febrile respiratory disease but this was less severe than that suffered by the controls and the amounts and duration of virus shedding were reduced.     

Dexamethasone and prednisolone in the horse: pharmacokinetics and action on the adrenal gland

Pharmacokinetics of dexamethasone and prednisolone were studied in 6 horses given dexamethasone alcohol (IV or IM) or dexamethasone 21-isonicotinate as a solution IV or IM (50 micrograms/kg of body weight), prednisolone 21-sodium succinate IV or IM (0.6 mg/kg of body weight), or prednisolone acetate IM (0.6 mg/kg of body weight). Plasma concentrations were determined using a high-performance liquid chromatographic method. After dexamethasone alcohol (IV) or dexamethasone 21-isonicotinate (IV), the half-life of elimination was similar (53 minutes) for both formulations. After dexamethasone (alcohol and isonicotinate, IM), concentrations were low or nondetected. After prednisolone 21-sodium succinate (IV), the half-life of elimination (99.5 minutes) was significantly (P less than 0.01) longer than that for dexamethasone. After prednisolone 21-sodium succinate (IM), absorption was rapid and bioavailability was high. After prednisolone acetate (IM), absorption was slow and prednisolone was present in plasma for about 7 days. Due to the nonlinearity of prednisolone kinetics, a bioavailability higher than 100% was obtained. The basal plasma hydrocortisone concentration was approximately 70 ng/ml. After dexamethasone (IV or IM), plasma hydrocortisone values decreased after a 2-hour delay and returned to base line after a 3 to 4 day delay. After prednisolone 21-sodium succinate (IV or IM), plasma hydrocortisone decreased immediately (IV) or rapidly (IM) and returned to base line after a 24-hour delay. After prednisolone acetate (IM), plasma hydrocortisone decreased for up to 21 days.