A tracheoscopic technique for obtaining uncontaminated lower airway secretions for bacterial culture in the horse

Transtracheal aspirate (TTA) aerobic microbiology culture results from 30 ponies were compared to protected catheter brush (PCB) culture results obtained from the same ponies. The PCB procedure resulted in significantly fewer (P less than 0.05) isolates than those obtained by the TTA procedure and the PCB procedure resulted in significantly more samples with no bacteria growth than the TTA procedure. To address the possibility that the volume of tracheobronchial secretion obtained by PCB was insufficient as a microbiological sample, a sterile, double-sheathed, protected aspiration catheter (PAC) was developed. Comparisons were made between TTA and PAC aerobic microbiology culture results from 18 pneumonic foals and weanlings. There were no significant differences between the PAC and TTA procedures with respect to the number of bacteria isolates. It was concluded that the PAC technique may be used as an alternative to TTA for isolation of equine pulmonary bacteria and may be the preferred procedure because of the reduced risk of complications associated with the TTA.     

Secretion of ovine lymphocyte suppressor factor from curetted uterine luminal cells.

The secretion of ovine lymphocyte suppressor factor from jugular vein (JV), uterine vein (UV), and curetted hemopoietic uterine luminal (UL) mononuclear cells was evaluated on d 14 of the cycle, following ovariectomy (OVX) and after 14 d of progesterone injections (OVX + P4, 1 mg/kg BW). Mononuclear cells (predominantly lymphocytes) were harvested by Ficoll-Paque and placed into culture (2.5 x 10(6).mL-1.well-1 in RPMI-1640). Cellular supernatants were obtained at 72 h and volumes (5 to 50 microL) were tested for suppression of phytohemagglutinin (PHA [.08 microgram l)-treated peripheral blood lymphocytes (1.0 x 10(5)). In a concurrent experiment, PHA-treated JV, UV, and UL cells (1.0 x 10(5)) were cultured singly and JV cells (1.0 x 10(5)) were also cocultured with each of 1.0 x 10(5), 5.0 x 10(4), and 2.5 x 10(4) UV and UL cells. The incorporation of thymidine into DNA was quantified at 60 h. For the cellular supernatant experiment, thymidine incorporation was affected by reproductive phase (P less than .036), lymphocyte source (P less than .0001), and phase x source (P less than .004). For UL cells, the degree of suppressor activity follows: d 14 greater than OVX greater than OVX+P4 (P less than .05). The UL supernatant from OVX+P4-treated ewes and supernatants of JV and UV cells, irrespective of reproductive phase, lacked suppressor activity. Sephacryl S-200 chromatography revealed that UL supernatant from d-14 ewes contained a greater than or equal to 248,000 molecular weight suppressor macromolecule. For the cellular coculture experiment, thymidine incorporation was affected by reproductive phase (P less than .05) and lymphocyte source (P less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Partial purification and characterization of proteins with growth promoting activities from ovine mammary gland secretions.

Developmental regulation of growth promoting activities in mammary secretions of pregnant Awassi ewes was defined, and growth factors contained in these secretions were partially purified and characterised. Mammary secretions from pregnant ewes enhanced fibroblast cell (AKR-2B) and mammary cell (CID-9 cell strain) proliferation to levels comparable to that induced by 10% Foetal calf serum. Major milk proteins in mammary secretions collected from pregnant ewes one month prior to lambing up to one week after lambing, were resolved by SDS-PAGE, while gelatinases were resolved by zymography. Gelatinase activity was noted prior to P134 and decreased thereafter to reach a minimum during lactation. This decrease was concomitant with the onset of casein production. It is during this critical developmental period that highest growth promoting activity in mammary secretions was detected.Secretions with highest growth promoting activity were fractionated by ion exchange and gel filtration chromatography. Two heat-resistant, trypsin/chymotrypsin sensitive, growth-promoting activities were characterised. The first, designated ovine mammary derived growth factor-1 (oMDGF-1), had around a 30 kDa molecular weight and eluted at 0.65 M NaCl gradient on cation ion exchange chromatography. The second, oMDGF-2, eluted under gel filtration conditions at a molecular weight of 50 kDa and 150 kDa. oMDGF-1 induced changes in Connexin 43, but not in beta-casein mRNA expression by CID-9 mammary cells.In conclusion, growth factor activities in ewe mammary secretions peak during gestation at a period that overlaps maximal gelatinase expression and precedes milk protein synthesis. The factors modulate mammary cell function and may play a role in mammary gland development.     

Variations in the virulence of strains of Chlamydia psittaci for pregnant ewes

Invasive and non-invasive strains of Chlamydia psittaci isolated from faeces of clinically healthy ewes and from vaginal swabs of ewes which had aborted were injected intravenously or intradermally into pregnant ewes. The results were studied by recording the ewes' thermal and serological responses, lambing performance and the excretion of chlamydia from the vagina. The differences between the effects of different invasive strains were greater after intradermal inoculation than after intravenous inoculation. After intradermal inoculation non-invasive strains did not disturb pregnancy (11 of 13 ewes lambed normally) whereas invasive strains induced abortion in 23 of 25 ewes, 24 of which excreted chlamydia in vaginal secretions.     

Effect of ovarian steroids on migration of uterine lumenal neutrophils and on chemokinetic factors in uterine secretions from mares

Incubation of blood neutrophils with uterine flushings collected from ovariectomised mares treated with oestradiol, stimulated migration under agarose, whereas flushings from mares treated with progesterone or oily vehicle, inhibited migration. After intra-uterine infusion of bacteria, however, flushings from oestradiol-treated and vehicle-treated mares inhibited migration, whereas progesterone treatment stimulated migration. Migration of uterine-derived neutrophils under agarose was less than that of blood neutrophils and was not influenced by treatment with ovarian steroids. Uterine susceptibility to infection in progesterone-treated mares was not, therefore, correlated with the migratory activities of uterine neutrophils or the chemokinetic properties of uterine secretions in vitro.     

Electronic feed stations for feeding concentrates to pregnant ewes on commercial sheep farms

ABSTRACT

The aim of this study was to investigate the use and capacity of electronic feed stations (EFS) on commercial sheep farms. The study was conducted on four commercial farms and the numbers of pregnant ewes per EFS were 36, 70, 72 and 80, respectively. Each farm was visited once and behavioural observations were carried out. In addition the date and time for both entering and leaving the EFS and the amount of concentrates dispensed at each visit for extracted. The vast majority of the ewes used the EFS regularly. The number of rewarded visits per ewe per day varied from 3.2 to 5.9, whereas the number of unrewarded visits ranged from 6.0 to 21.5 per ewe per day. We conclude that feeding concentrates to groups of pregnant ewes in EFS function satisfactory, but the design of the entrance and exit gate still have to be improved considerably.     

Method for obtaining bovine zygotes produced in vivo

A superovulatory and surgical protocol was developed for recovery of bovine zygotes. Holstein cows and heifers were given follicle-stimulating hormone and cloprostenol to induce superovulation. Surgical cannulation and lavage of the uterine tube was performed 40 to 48 hours after the start of standing estrus. In general, cows had more corpora hemorrhagica than did heifers, but a higher percentage (P less than 0.05) of ova recovered from cows were infertile. Several heifers were subjected to the procedure twice, and embryo recovery rates were equivalent both times.     

Evaluation of an enzyme immunoassay for detection of Chlamydia psittaci in vaginal secretions, placentas, and fetal tissues from aborting ewes

A commercially available enzyme immunoassay (EIA) for the detection of Chlamydia trachomatis in human urogenital and conjunctival specimens was compared with isolation in cell culture for the detection of Chlamydia psittaci in vaginal and placental swabs from aborting ewes and swabs of aborted fetal tissues. The EIA on vaginal swabs collected from 10 ewes experimentally infected with C. psittaci had a sensitivity of 85.7% and a specificity of 85.7%. Vaginal swabs collected at the time of abortion or within 3 days were the best samples for detection of chlamydial infection. The 29 vaginal swabs collected during this period from experimentally infected ewes were all strongly EIA-positive, and chlamydia were isolated from 28. The EIA on vaginal swabs from 78 field cases of abortion had a sensitivity of 78.0% and a specificity of 76.8%. The EIA on swabs of cotyledons from 65 placentas had a sensitivity of 100% and a specificity of 75.0% compared with isolation in cell culture. The EIA on 57 swabs of fetal tissues or body fluids from 10 aborted fetuses or weak lambs from experimentally infected ewes had a sensitivity of 26.6% and a specificity of 88.1% compared with isolation in cell culture. Limitations of the EIA are discussed.     

Elimination of [14C]heptachlor from body stores of lactating ewes treated with ovine growth hormone

Elimination of [14C]heptachlor from body burdens of sheep was measured using mature ewes nursing single offspring, and the influence of exogenous ovine growth hormone (oGH) on elimination was studied. Six ewes (62 +/- 2.5 kg BW) were dosed (i.p.) once with [14C]heptachlor (2.04 mg/kg Bw; .88 microCi/mg heptachlor) and three were treated additionally with oGH (oGH; 5 mg/d) for 21 d. Three additional ewes served as controls. Excreta were collected each day for 21 d. Milk and blood were collected every 3rd d until ewes were euthanized at d 21. 14C activity was measured in excreta, milk, blood and tissues. Total cumulative activity of [14C]heptachlor and(or) metabolites in excreta (21 d) did not differ (P greater than .20) in ewes given oGH (25 +/- 2%) vs none (23 +/- 2%). Milk yield and protein content were unaffected (P greater than .10) by oGH. Ewes given oGH eliminated 2.2 +/- 2% of total 14C dosage into milk during 21 d, whereas ewes untreated with oGH eliminated 1.3 +/- .2% (P less than .10); total 14C activity eliminated into milk plus excreta was similar for ewes given oGH or none (P greater than .10). For all six ewes, half-times (T1/2) for distribution and elimination of 14C activity (heptachlor and metabolites) were 1.5 d and 11.7 d, respectively. Blood concentrations of 14C activity during 21 d yielded elimination half-time as 23 d. Unlike bovines, which eliminate heptachlor slowly (T1/2 approximately 70 to 80 d) and mainly into milk fat, lactating ovines eliminated heptachlor and(or) metabolites mainly into excreta and about sixfold faster than bovines.     

Evaluation of sodium carboxymethylcellulose for prevention of adhesions after uterine trauma in ewes.

Efficacy of a 1% solution of sodium carboxymethylcellulose (CMC) infused into the peritoneal cavity of ewes was evaluated for prevention of intraperitoneal adhesions resulting from surgery of the reproductive tract. Six ewes were assigned to each of 4 groups. Group-1 ewes were controls that underwent ventral midline celiotomy and exploration of the abdominal viscera. Group-2 ewes were treated similarly to group-1 ewes, except that a 1% solution of CMC (14 ml/kg of body weight) was infused into the peritoneal cavity. This group was studied to determine whether CMC would cause changes in the peritoneal cavity. Group-3 comprised ewes representing a uterine trauma model. Ewes underwent abdominal exploration, but in addition had a standard embryo collection technique performed on 1 uterine horn and hysterotomy performed on the opposite uterine horn. Group-4 ewes were treated like group-3 ewes, except that, similar to treatment of group-2 ewes, CMC was infused into the peritoneal cavity. All ewes were euthanatized and necropsied 12 to 14 days after surgery. Abdominal adhesions were evaluated, and an adhesion severity score was assigned to each ewe on the basis of number and severity of the adhesions. Ewes of all groups had abdominal adhesions. Significantly (P less than 0.05) lower adhesion score was observed in ewes given CMC (groups 2 and 4) than in the adhesion model (group 3). Significant difference was not observed in adhesion score when groups 1, 2, or 4 were compared. Though not statistically significant, fewer adhesions were observed in ewes of groups 2 and 4 than in group-1 ewes.     

Accreditation for freedom from ovine brucellosis

The results of operating a voluntary ovine brucellosis accreditation programme in 14 stud and 9 commercial flocks in the Manawatu district is reported. From a total of 1992 CF test results there were 47 positive and 14 suspicious reactions; a total of 61 reactions (3.06%). Fifty six of these occurred in rams vaccinated during the previous 12 months, and only one further ram with epididymitis had a suspicious, and then a positive, CF test and is assumed to have had brucellosis (0.05%). One of the remaining three suspicious reactions was confirmed as a false suspicious, and the other two remain unclassified as either true or false. It was concluded the CF test is both highly sensitive and specific, and that the official acceptance of accreditation schemes is an urgent priority for the sheep industry.     

Experimental aerosol infection of cattle (Bos taurus) with ovine herpesvirus 2 using nasal secretions from infected sheep

Infection of clinically susceptible ruminants, including domesticated cattle and American bison, with ovine herpesvirus 2 (OvHV-2) can result in the fatal lymphoproliferative and vasculitis syndrome known as malignant catarrhal fever (MCF). A reliable experimental infection model is needed to study the pathogenesis of MCF and to develop effective vaccination strategies to control the disease. An experimental aerosol infection model using sheep, the natural carriers of OvHV-2, has been developed (Taus et al., 2005). Using the protocol and OvHV-2 inoculum established in the previous study, eight calves were nebulized with four different doses of OvHV-2 in nasal secretions from infected sheep. Two control calves were nebulized with nasal secretions from uninfected sheep. Infection status of all calves was monitored using competitive inhibition ELISA, PCR and clinical parameters. Six of eight nebulized calves became infected with OvHV-2. One calf receiving the highest dose of virus developed typical clinical, gross and histological changes of MCF. This study showed that nasal secretions collected from sheep experiencing OvHV-2 shedding episodes were infectious for cattle and capable of inducing MCF. The data also indicate that cattle are relatively resistant to disease following infection. The use of more susceptible species as experimental animal models, such as bison and selected cervid species should be examined.