Identification of a mutant bovine herpesvirus-1 (BHV-1) in post-arrival outbreaks of IBR in feedlot calves and protection with conventional vaccination.

Outbreaks of infectious bovine rhinotracheitis (IBR) have recently been observed in vaccinated feedlot calves in Alberta a few months post-arrival. To investigate the cause of these outbreaks, lung and tracheal tissues were collected from calves that died of IBR during a post-arrival outbreak of disease. Bovine herpesvirus-1 (BHV-1), the causative agent of IBR, was isolated from 6 out of 15 tissues. Of these 6 isolates, 5 failed to react with a monoclonal antibody specific for one of the epitopes on glycoprotein D, one of the most important antigens of BHV-1. The ability of one of these mutant BHV-1 isolates to cause disease in calves vaccinated with a modified-live IBR vaccine was assessed in an experimental challenge study. After one vaccination, the majority of the calves developed humoral and cellular immune responses. Secondary vaccination resulted in a substantially enhanced level of immunity in all animals. Three months after the second vaccination, calves were either challenged with one of the mutant isolates or with a conventional challenge strain of BHV-1. Regardless of the type of virus used for challenge, vaccinated calves experienced significantly (P < 0.05) less weight loss and temperature rises, had lower nasal scores, and shed less virus than non-vaccinated animals. The only statistically significant (P < 0.05) difference between the 2 challenge viruses was the amount of virus shed, which was higher in non-vaccinated calves challenged with the mutant virus than in those challenged with the conventional virus. These data show that calves vaccinated with a modified-live IBR vaccine are protected from challenge with either the mutant or the conventional virus.

Clinical efficacy and tolerance of meloxicam in dogs with chronic osteoarthritis.

A clinical trial was conducted to evaluate the safety and efficacy of the nonsteroidal anti-inflammatory drug meloxicam in dogs with chronic osteoarthritis. Forty clinical cases were enrolled in the 2-phase study. Phase 1 compared therapeutic efficacy and tolerance of meloxicam or placebo for 1 week. Phase 2 involved a 4-week evaluation of the drug's clinical efficacy and tolerance. Clinical efficacy was evaluated by using a scoring system that assessed specific lameness, general stiffness, painful rise, exercise intolerance, and behavior. Evaluations demonstrated significant reductions (P < 0.05) in clinical signs of osteoarthritis following 4 weeks of drug therapy. Side effects were minimal in extent and duration. The drug was accepted without problems in the majority of cases. The findings of this investigation suggest that the efficacy, tolerance, and formulation of meloxicam oral suspension make it well suited for the treatment of chronic osteoarthritis in the dog.

The effect of intrauterine inoculation with Ureaplasma diversum on bovine fertility.

To determine the influence of Ureaplasma diversum on bovine fertility 11 uninfected virgin heifers with normal ovarian cyclic activity were randomly allocated to test or control groups. At a synchronized estrus, five test heifers were given an intrauterine broth inoculum containing 1.09 x 10(8) to 1.4 x 10(9) colony forming units of U. diversum and six control animals were infused with sterile ureaplasma broth medium. All animals were artificially inseminated within one hour of infusion. Pregnancy was diagnosed in one of five test heifers and all of six controls by serum progesterone concentrations measured to 25 days postinsemination. The difference in pregnancy rates between the two groups was statistically significant (p = 0.0152). It was concluded that under the conditions of this experiment U. diversum is capable of causing infertility in cattle.

Effects of gonadotrophin releasing hormone on reproductive performance of dairy cows with retained placenta.

The effects of gonadotrophin releasing hormone (GnRH) on the reproductive performance of dairy cows with retained placenta were studied. Three hundred and seventy-eight cows diagnosed as having retained placenta received intramuscular injections of either 2 mL sterile water or 200 micrograms of GnRH in 2 mL sterile water between day 8 and day 14 postpartum. Rectal palpation was performed at the time of treatment and ten to 20 days after treatment in order to determine the rate of uterine involution. Thereafter, monthly rectal examinations were carried out until insemination. Pregnancy diagnosis was made by rectal palpation at 40 days or more after breeding. Using the entire experimental population, there were no significant differences between GnRH-treated and control cows for the rate of uterine involution, the occurrence of reproductive problems, the interval from parturition to first observed estrus, the interval from parturition to first insemination, the interval from parturition to conception, the number of services per conception, the total number of services per cow regardless of conception and the incidence of culling for infertility. When the data for herds in which breeding began earlier in the postpartum period (herds having a mean less than or equal to 80 days from parturition to first service for retained placenta cows) were considered, the GnRH treatment resulted in a significantly shorter (p less than or equal to 0.01) calving to conception interval as compared to control cows. Also, there was a significant reduction (p less than or equal to 0.05) in the total number of services per cow regardless of conception and a significant reduction in the interval from parturition to first service.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproductive performance in dairy cows following postpartum treatment with gonadotrophin releasing hormone and/or prostaglandin: a field trial.

Three hundred and five Holstein Friesian cows were given either 250 micrograms gonadotrophin releasing hormone (GnRH) or saline on day 15 postpartum followed by 500 micrograms cloprostenol or saline on day 24 postpartum. Four treatment groups were formed using random allocation: Group I -- placebo (Day 15)/placebo (Day 24), Group II -- GnRH (Day 15)/placebo (Day 24), Group III -- placebo (Day 15)/cloprostenol (Day 24), Group IV -- GnRH (Day 15)/cloprostenol (Day 24). Double blind techniques were used during the follow-up period. Rectal palpation, to assess uterine involution and ovarian activity was performed just prior to each treatment and again at 28 days postpartum. In addition blood samples were collected at 15, 24 and 28 days postpartum for measurement of plasma progesterone. There were no significant differences among treatment groups with respect to services per conception, number of heats detected before first service and culling for infertility. Cows treated only with GnRH had an increased calving to first estrus and calving to first breeding interval, and tended to have an increased calving to conception interval. Treatment with cloprostenol significantly decreased calving to conception and calving to first observed estrus intervals. Treatment with GnRH on day 15 postpartum resulted in a significant increase in the subsequent incidence of pyometra and prebreeding anestrus. On the other hand, cloprostenol treatment on day 24 postpartum resulted in a decreased incidence of pyometra, regardless of GnRH treatment and a decreased incidence of prebreeding anestrus in GnRH treated cows compared to cows receiving only GnRH at day 15 postpartum.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine abortion and neonatal death associated with Ureaplasma diversum.

Ureaplasma diversum was isolated from the lungs and/or stomach fluid and placentas of five aborted bovine fetuses and four newborn calves. All isolates were serotype D48. Placentitis was observed in all instances in which the placenta was examined. Gross lesions consisted of focal or diffuse reddening of the chorioallantois and amnion and thickening of the amnion. Microscopically there were fibrosis, edema and inflammation of the amnion. Microscopic lesions in the lung consisted of diffuse pneumonitis with thickening of the alveolar walls and in some cases peribronchiolar lymphoid accumulations. Macrophages and granulocytes were present in the alveoli. Inoculation of the vulva of a virgin heifer with one of the isolates from a fetal lung produced hyperemia and profuse purulent discharge with slight granularity.

The effects of Ureplasma diversum inoculated into the amniotic cavity in cows.

Ureaplasma diversum was inoculated into the amniotic cavity in four cows. Two calves were aborted and two were born alive. One of the latter died shortly after birth and the other was killed. The cows remained clinically normal except that three retained their placenta. On microscopic examination there was a severe placentitis and an alveolitis was present in the lungs of all calves. Ureaplasma was recovered from four placentas and three lungs. Cows remained infected for a maximum of 132 days following inoculation and the organism was recovered in urine and vulvar swabs for a maximum of 17 and 60 days respectively following expulsion of the calf. Ureaplasma diversum has been isolated from natural cases of abortion with similar lesions. This experiment strongly supports a causal relationship between abortion, birth of calves with pneumonia and U. diversum infection.

Prevalence and distribution of Haemophilus somnus in the male bovine reproductive tract.

"Haemophilus somnus' was isolated from 77% of 31 reproductive tracts of bulls from an Ontario slaughterhouse. Identification of H somnus was based on morphologic and cultural characteristics and on fluorescent antibody and immunodiffusion tests, using antisera prepared against a known pathogenic encephalitic isolate of H somnus. The infection rate and distribution of H somnus within the tract were as follows: preputial orifice--71% preputial cavity--71%; urinary bladder--26%; accessory sex glands--19% and ampulla of ductus deferens--10%. Isolates were not obtained from the testes or epididymides. On 2 occasions, H somnus was isolated in pure culture from the preputial cavity. A higher prevalence of infection was found in young bulls. There were no differences found in infection rates between breeds. Differences in hemolytic activity and minor antigenic variation between isolates indicated that a series of biotypes within the species H somnus may exist. The study indicates that organisms presently identified as H somnus may normally form part of the flora of the bovine prepuce and that dissemination from the male bovine reproductive tract is one possible means of infection in H somnus-associated diseases. The pathogenic significance of genital isolates of H somnus awaits further study.

Occurrence of "Haemophilus somnus" in bovine semen and in the prepuce of bulls and steers.

Haemophilus somnus was isolated from 40 of 79 unprocessed bovine semen samples, 14 of 23 preputial washings of bulls and three of eight preputial washings of steers. The results indicate nonvenereal colonization of the male urogenital tract. It is suggested that dissemination of H. somnus from the urogenital tract may be of significance in the epizootiology of H. somnus associated diseases.

A quantitative study of the histological morphology of the endometrium of normal and barren mares.

The density of uterine glands, height of surface epithelium, numbers of hemosiderin laden macrophages, inflammatory cells and layers of periglandular fibrosis were evaluated in uterine biopsies from 40 mares. These features were found to be highly variable in normal equine endometrium. Minor pathological changes appeared to be masked by this normal variability. Atrophy of uterine glands was recognized in mares which had been barren for more than three years. No significant differences were found between barren and normal mares in the height of epithelium, number of hemosiderin laden macrophages, inflammatory cells or layers of collagen surrounding glands in the superficial portion of endometrium. The number of layers of fibrosis surrounding glands in the deep part of lamina propria were found to be correlated with years of barrenness. This finding appears to have prognostic potential.

Bovine genital mycoplasmosis.

Infection, lesions and clinical significance of Acheloplasmas, Mycoplasma bovis and Mycoplasma bovigenitalium in genital disease of cattle are described. A more detailed account is given of ureaplasma infections. Acute and chronic forms of granular vulvitis in both field and experimental disease are described as well as the role of the organism in abortion. Recovery rates of ureaplasma and mycoplasma from semen and preputial washings in bulls are outlined and their significance in disease is discussed. There are problems in differentiating pathogenic from nonpathogenic isolates. Methods are being developed to treat semen for these organisms. This paper provides a concise summary of clinical and microbiological aspects of bovine genital mycoplasmosis.

The genital Mycoplasma and Ureaplasma flora of healthy and diseased dogs.

The genital mycoplasma and ureaplasma flora was compared in 136 dogs with varied reproductive histories. Mycoplasmas were recovered from 88% of vulvovaginal swabs, 85% preputial swabs and 72% semen samples. Isolation rates were slightly higher from dogs that were infertile or had evidence of genital disease but the differences from those that were fertile or clinically normal were statistically significant only in the male. Ureaplasmas were recovered from half the females sampled. Higher, but not statistically significant isolation rates (75%) were made from infertile females with purulent vulvar discharge versus those that were clinically normal and fertile (40%). In the male dog there was a significantly higher incidence of ureaplasmas in the prepuce of infertile animals (69%) than those that were fertile (0%) (p less than or equal to 0.05). Semen isolations although not significantly higher in infertile males, were all made from ejaculates, with subnormal motility, low sperm counts and/or a high percentage of midpiece and tail abnormalities (bent or tightly coiled).

The use of endometrial biopsy in the infertile mare.

The results of a study on endometrial biopsies obtained from 700 infertile mares are reported. Infiltrative endometritis was present in 51% consisting of a combination of an acute and chronic cellular response in 6%, mild chronic infiltrations in 35% and moderate to severe chronic infiltrations in 10%. Demonstrable endometrial fibrosis was found in 88% of the mares with the majority having mild (51%) or moderate (35%) changes. The age of the mares and the average number of years barren gradually increased with the severity of endometrial fibrosis, as did the combined incidence of fetal loss (early embryonic death and abortion) during the three year period preceding the biopsy.A significant decrease in foaling percentage for the year following the biopsy was observed with increasing severity of endometrial fibrosis. Chisquare analysis projected a decrease in foaling rate of 22.8% for each category increase in severity. The number of years barren and the farm management system used also had a significant effect on foaling probability. The foaling rates for mares that were bred artificially (82%) under strict veterinary supervision using an extender incorporating gentamicin were significantly (P < 0.05) higher than for mares bred in a conventional manner under average management conditions (48%). It was concluded that endometrial biopsy is a valuable diagnostic and prognostic technique. When the degree of fibrosis is used to predict foaling probability, the number of years barren and the breeding method to be used should also be considered to arrive at a more accurate prediction.

Pregnancy and peripheral plasma progesterone levels in cows inseminated after synchronization of estrus with prostaglandin F2 alpha.

Fifteen Holstein cows were treated with two doses of 25 mg of a prostaglandin F(2)alpha (PGF(2)alpha as dinoprost tromethamine) administered intramuscularly 11 days apart. The cows were then divided into three groups and inseminated either at 72, 80 or 72 and 96 hours after the second dose of PGF(2)alpha. Thirteen cows ovulated after the second prostaglandin treatment. Eight cows were diagnosed pregnant by rectal palpation 42 days after insemination but only five calved. PGF(2)alpha induced luteolysis in cows with active corpora lutea as evidenced by the dramatic decreases in the plasma progesterone concentrations after treatment. In contrast, following PGF(2)alpha administration to cows in follicular or late luteal phase the concentrations of plasma progesterone either increased gradually or remained low for several days before increasing to maximal levels. The ovulatory rate after the two doses of PGF(2)alpha11 days apart was high. However, the pregnancy rate after this treatment was influenced by other factors including abnormal ovarian function.

Experimental bovine genital ureaplasmosis. I. Granular vulvitis following vulvar inoculation.

Granular vulvitis was reproduced in ten virgin heifers following vulvar inoculation with strains of ureaplasma previously isolated from natural cases. The disease appeared one to three days postinoculation and was characterized by vulvar swabs but not from the upper mucopurulent discharge. At necropsy 13 to 41 days later, ureaplasmas were recovered consistently from vulvar swabs but not from the upper reproductive tract. It was concluded that some strains of ureaplasma are pathogenic and should be viewed as a cause of bovine granular vulvitis.

Experimental bovine genital ureaplasmosis. II. Granular vulvitis, endometritis and salpingitis following uterine inoculation.

Twenty-three virgin Holstein heifers received uterine inoculations with ureaplasma and were necropsied one to thirteen days later. Three heifers inoculated intracervically were necropsied on days 3, 5 and 11.Granular vulvitis was produced on average by 3.6 days in fourteen of sixteen uterine inoculated heifers monitored for four or more days. Two cervically inoculated heifers monitored for over four days also developed granular vulvitis by the fourth day. At necropsy, ureaplasma was recovered from 94% of uterine horn cultures for the first four days postinoculation and 50% during days 5 to 7. Thereafter all uterine cultures were negative. The percentage of positive ureaplasma recoveries from uterine tube flushings was lower than for uterine horns but remained positive for a longer period. By day 7, three of four uterine tube flushings were still positive. No bacterial pathogens were isolated from the uterine horns or uterine tube flushings. On histopathology 50% of uterine inoculated heifers had endometritis up to six days postinoculation and a slightly higher percentage (58%) had salpingitis. Endometritis was not found in any heifers after day 6. Residual salpingitis was present in one heifer on day 7. Endometritis was present in cervically inoculated heifers necropsied on days 3 and 5 but not on day 11. Salpingitis was not found in any of the three cervically inoculated animals. The study concluded that some strains of ureaplasma are pathogenic for the upper reproductive tract of the cow and should be considered significant when isolated from cases of granular vulvitis, endometritis or salpingitis.