Evaluation of numbers of microscopic and macroscopic follicles in cattle selected for twinning

We hypothesized that the number of microscopic follicles present in the ovaries of cattle selected for twin births (Twinner) would be greater than in the ovaries of contemporary Controls. Ovaries were collected from seven Control and seven Twinner cows at slaughter. The number of Small (1 to 3.9 mm), Medium (4 to 7.9), and Large (> 8 mm) surface follicles was counted and one ovary was fixed for histological evaluation. Fifty to sixty consecutive 6-microm slices were taken from a piece of cortical tissue, approximately 1 cm x 1 cm in area, located between the surface follicles. Microscopic follicles were classified as primordial (oocyte surrounded by a single layer of squamous pregranulosa cells), primary (oocyte surrounded by a single layer of one or more cuboidal granulosa cells), secondary (oocyte surrounded by two or more layers of granulosa cells), or tertiary (oocyte surrounded by multiple layers of granulosa cells with initiation of antrum formation to < or = 1 mm in diameter). The total number of follicles was counted in 200 fields (2 mm x 2 mm) per ovary. A field containing no follicles was classified as empty. There were significantly more secondary follicles in Twinner compared with Control ovaries (12.9 vs 6.3; P < .05). Twinners also tended to have more small surface follicles (35.4 vs 49.0; P < 0.1). We conclude that ovaries of Control and Twinner cows do not differ in the number of primordial follicles or in the number of follicles activated into the growing pool; however, Twinner cows are able to maintain more growing follicles at the secondary and subsequent stages of development.     

Initial results of genomic scans for ovulation rate in a cattle population selected for increased twinning rate

Genomic scans were conducted with 273 markers on 181 sires from a cattle population selected for increased twinning rate to identify chromosomal regions containing genes that influence ovulation rate. Criteria used for selecting markers were number of alleles, ease of scoring, and relative position within linkage group. Markers were multiplexed or multiple-loaded on the gels to reduce the costs and labor required to obtain genotypic data. This approach reduced the number of gels by 45% when compared with running each marker independently. Male animals selected for the genomic scan sired the majority of the population. A modified interval analysis was used in a granddaughter design to compare effects of each allele within sire for 10 different sire families. The midparent deviation of the son's estimated breeding value for ovulation rate was used as the phenotype. Forty-one potential peaks were identified with a nominal significance level < or = 0.05. The 10 peaks with the highest significance levels (P < 0.02) were selected for further analysis. Markers were genotyped across daughters of the sire where nominal significance was found for each of the 10 peaks. One peak (BTA5, relative position 40 cM) was found to be nominally significant in the daughters. The nominal significance levels were P = 0.01 for the sons (n = 32) and P = 0.02 for the daughters (n = 94) of sire 784403. A combined genomewide significance value (P = 0.07) was calculated that accounted for the 10 analyses with sons and the 10 analyses with daughters. These results strongly suggest that this region contains a gene(s) that is involved in the follicular recruitment and development process.     

Expression of the porcine beta2-adrenergic receptor in Chinese hamster ovary cells

The gene for the porcine beta2-adrenergic receptor (pbeta2AR) was transfected into Chinese hamster ovary (CHO) cells for expression. Fourteen stable cell lines were obtained and exhibited receptor densities ranging from 12 to 2,371 fmol/mg membrane protein. The receptor density was not correlated with estimates of gene copy number obtained by Southern hybridization. The pbeta2AR in CHO cells exhibited saturable binding of [125I]CYP (Kd = 14.5 pM) and stereospecificity for (-)- and (+)-isoproterenol. The relative affinities for (-)-isoproterenol (ISO), (-)-epinephrine (EPI), and (-)-norepinephrine (NEPI) were ISO > EPI > NEPI, which are characteristic of beta2AR. The affinity values for these ligands were similar to those in other species. Binding of ISO, EPI, and NE revealed two affinity states of the betaAR; the high-affinity state was eliminated by adding Gpp(NH)p, a nonhydrolyzable GTP analogue. Binding of the antagonist propranolol modeled to only one affinity state, and Gpp(NH)p did not affect binding. Multiple affinity states are characteristic of agonist-induced coupling of betaAR with G-proteins, and the data suggest that the cloned pbetaAR is functionally competent. Data confirm that the pbeta2AR is the pig version of beta2AR. Stable CHO cell lines will be useful for characterization of pbeta2AR and screening and designing potential drugs that may be used to enhance pig production.     

Effects of food withdrawal and transport on 5- to 10-day-old calves

The effects of food withdrawal for 30 hours and transport for up to 12 hours on 5- to 10-day-old calves were determined by monitoring plasma concentrations of glucose, beta-hydroxybutyrate, urea, lactate and creatine phosphokinase. In addition gamma-glutamyl transferase activity, packed cell volume, total plasma protein concentration, bodyweight and rectal temperature were recorded. Food withdrawal for 30 hours caused hypoglycemia but calves maintained normothermia and although their beta-hydroxybutyrate level increased indicating lipid mobilisation, the changes in blood urea level were minimal indicating low amino acid catabolism. When calves were transported for 12 hours in addition to having food withdrawn for 30 hours, they remained normoglycemic for six hours longer than non-transported calves, probably due to an effect of muscular activity during bracing against truck movements. Stocking calves at a lower density during transport apparently had a beneficial effect, as calves were able to lie down throughout the journey and therefore produced a similar metabolic profile to resting, non-transported animals. Transport and food withdrawal had no obvious effects on calf hydration. The results of this study suggest that food withdrawal for up to 30 hours and transport for up to 12 hours had no detrimental effects on the metabolism of healthy and clinically normal calves. With correct feeding regimes and transport protocols, welfare compromise in young, healthy calves being transported for up to 12 hours can be minimised when they are slaughtered within 30 hours of the start of transport.     

The virulence and protective efficacy for chickens of pasteurella multocida administered by different routes

The relative virulence for chickens of five strains of Pasteurella multocida was evaluated. Twenty groups, each of ten chickens, were inoculated with a standard dose of 10(5) of each of five strains by the intramuscular (I.m.), intravenous (I.v.), intratracheal (I.tr.) or conjunctival (Co) routes. The highest mortality occurred in the groups dosed I.m. and I.v., followed by I.tr. inoculation. The relative virulence of each strain did not change when inoculated by the different routes. The most virulent strain, VP161, caused 100% mortality by all except the Co route. The least virulent strain, VP17, caused a single mortality by the I.v. route, but gave a high level of protection to birds inoculated by both the I.m. and I.v. routes, when challenged by intramuscular injection with (VP161). There was no protection against I.m. challenge in the birds inoculated by the I.tr. or Co routes. Serum antibody levels measured by ELISA correlated with the level of protection against virulent challenge for groups inoculated I.m. or I.v., but not I.tr. Western blots of pooled sera from each group did not show any specific antigen recognition that might explain the observed differences in protection. Inoculation with strain VP17, (both I.m. and I.tr.) also gave a high level of protection to birds challenged with strain VP161 by intratracheal instillation.     

Clinical evaluation of methoximorpholino-doxorubicin (FCE 23762) in dogs with spontaneous malignancies

We conducted a clinical evaluation of FCE 23762, a methoxymorpholino analog of doxorubicin, in 48 dogs with metastatic, nonresectable, or chemotherapy-resistant spontaneous malignancies at an initial dosage of 50-60 microg/kg IV every 3 weeks. Clinical evidence of toxicity was minimal; 6 dogs developed grades I, II, and III hematologic toxicities after the 1st treatment, and 1 dog developed grade II gastrointestinal toxicity. One dog became pancytopenic 4 months after discontinuation of FCE 23762. No other adverse effects were noted. Partial or complete remissions were observed in 32% of the dogs. Responses were observed both in previously untreated dogs and in those that had received prior chemotherapy, including doxorubicin. FCE 23762 is a promising new antineoplastic agent that can be used safely in dogs with cancer; doses higher than those used in this study may be used eventually in practice.     

Posterior lamellar keratoplasty for treatment of deep stromal absesses in nine horses

OBJECTIVE: To describe and evaluate the use of posterior lamellar keratoplasty as a surgical treatment for deep corneal stromal abscesses in horses. Animals studied Nine horses of various breeds and ages that presented with corneal stromal abscesses located in the posterior one-third of the cornea. Procedure Retrospective medical record study. RESULTS: Nine horses had deep corneal stromal abscesses that were treated with posterior lamellar keratoplasty. Median patient age was 3 years. Six patients were females and three were geldings. Medical therapy alone had been attempted prior to surgery in all nine animals. Corneal abscess culture and histopathology were performed in 8/9 horses. Cultures were positive for an infectious etiology in 4/8 (50%). Histopathology was positive for an infectious etiology in 5/8 (62.5%). Mean surgical time was 71.0 +/- 18.8 min and the average healing time was 23.7 +/- 5.2 days. Visual outcome was positive in 8/9 cases. Conclusion Posterior lamellar keratoplasty is a promising procedure for treatment of deep corneal stromal abscesses in horses. The procedure resulted in considerable shorter surgery time and healing time than had been observed with full-thickness penetrating keratoplasty. Scar formation with this procedure was not significantly different than with penetrating keratoplasty.