The Effects of Cryopreservation on the Morphometric Dimensions of Iberian Red Deer (Cervus elaphus hispanicus) Epididymal Sperm Heads

Computer-automated sperm-head morphometry was used in this study to determine the effects of cryopreservation on red deer sperm-head morphometry. Epididymal sperm samples were collected from 40 mature stags and were divided. One portion was diluted at room temperature in a Tris-citrate egg yolk medium, containing 6% glycerol. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours. After thawing, sperm smears were prepared as described above. All slides were air dried and stained with Hemacolor. The sperm-head dimensions for length, width, area, perimeter and shape factor (length/width), for a minimum of 135 spermatozoa were determined for each slide by means of the Sperm-Class Analyser (SCA). Firstly, our results show that cryopreservation substantially reduced (p < 0.001) sperm motility and plasma membrane and acrosome integrities. In addition, sperm heads were significantly smaller in cryopreserved spermatozoa than in the companion extended samples for area (32.05 microm2 vs 32.56 microm2; p < 0.05), length (8.46 microm vs 8.53 microm; p < 0.0001) and shape factor (1.833 vs 1.849; p < 0.0001) for all stags. These differences were found within 29 of 40 stags (75%) for at least three of the morphometric parameters. The individual variability (CV) of sperm head measurements from extended samples was negatively correlated (p < 0.005) with the per cent of change in sperm head measurements after cryopreservation for area (r = -0.465), width (r = -0.483) and perimeter (r = -0.375). Thus, the lower the sperm head variability in the extended samples, the greater the sperm change as a consequence of the cryopreservation. These results suggest that the variability (heterogeneity) in sperm head dimensions of individual stags may be a good indicator of sperm freezability.     

The effect of feeding on the pharmacokinetic variables of two commercially available formulations of omeprazole

The objectives of this study were to investigate the impact of formulation (enteric coated and buffered) and feeding on pharmacokinetic variables associated with the oral administration of omeprazole in the horse. Six thoroughbred racehorses were studied in a crossover design. Each received 2 g of an enteric coated or buffered formulation in both the fed and fasted state. Plasma omeprazole concentrations were determined by UHPLC‐MS. The effects of feeding or formulation on AUC_{0‐inf_obs}, half‐life, T_max or C_max were not statistically significant. However, a wider‐than‐expected degree of variation was present and examination of the raw data suggests that an effect of feeding, wherein the bioavailability of omeprazole may be reduced in the fed animal, may be present. Further investigation in a larger population of animals to assess the factors that contribute to the wide degree of absorption observed is warranted.     

Effect of passive stretching on the range of motion of osteoarthritic joints in 10 labrador retrievers

Ten labrador retrievers and their owners undertook a programme to determine the effect of passive stretching on the dogs' osteoarthritic joints, which had a restricted range of motion. The range of motion of the joints was measured before and after the 21-day study, during which the owners performed 10 passive stretches for a hold of 10 seconds twice daily. Goniometric measurements showed that the passive stretching had significantly increased the range of motion of the joints.     

Magnetic microstructure of magnetotactic bacteria by electron holography

Off-axis electron holography in the transmission electron microscope was used to correlate the physical and magnetic microstructure of magnetite nanocrystals in magnetotactic bacteria. The magnetite crystals were all single magnetic domains, and the magnetization directions of small superparamagnetic crystals were constrained by magnetic interactions with larger crystals in the chains. Shape anisotropy was found to dominate magnetocrystalline anisotropy in elongated crystals. A coercive field between 300 and 450 oersted was determined for one chain.     

Health status of bulls used for natural breeding on farms in south west Scotland.

One hundred and nine breeding bulls were examined during the period November 1992 to June 1993 on farms in south west Scotland for evidence of infectious diseases associated with breeding. Preputial washings were collected to screen for Campylobacter fetus venerialis, together with serial blood samples to assess their seroprevalence to Bovine Virus Diarrhoea virus (BVDv), Bovine Herpes Virus-1 (BHV-1), Leptospira hardjo and Bovine Herpes Virus-4 (BHV-4). The possible impact of natural mating on the epidemiology of these diseases is described. Evidence of infections with Campylobacter fetus and BVH-4 were not found in this sample. The overall seroprevalence to BVDv was 78%, for BHV-1 49%, and L. hardjo 27% at titres of > or = 1/400. This study shows that bulls may be responsible for the introduction and dissemination of these diseases when moved from farm to farm as part of normal cattle breeding in this area. Young unproven bulls may be particularly susceptible to endemic diseases associated with lowered reproductive performance.     

POWER CORE SAMPLING OF FRESH FORAGE IN SMALL PLOT EXPERIMENTATION

A power-driven corer, designed to collect internally samples cored from small plot forage cuts of about 5–15 kg, is described. Sampling errors for percentage DM are shown to be lower than those associated with conventional practices; smaller than usual sample weights (200 g) which are less demanding on oven space are shown to be feasible, and the tedium of the sampling procedure is alleviated.     

THE ASSESSMENT OF THE NUTRITIVE VALUE OF SILAGE BY DETERMINATION OF IN VITRO DIGESTIBILITY ON HOMOGENATES PREPARED FROM FRESH UNDRIED SILAGE

A report is presented on studies on the relationship between in vitro digestibility of 18 silage samples and their in vivo digestibilities. Various analytical techniques are compared and the method adopted, on grounds of suitability for routine operation and accuracy of prediction of in vivo data, is based on analysis of homogenates of fresh silage. The homogenates, sufficiently uniform to permit of volumetric subsampling at acceptable error levels, are prepared in a new design of homogenizer. The impact of the % dry matter of the silage, as fed, on the accuracy of in vitrol in vivo relationships is considered and a bivariate regression plane is proposed.