Effect of different mini‐volume colloid centrifugation configurations on flow cytometrically sorted sperm recovery efficiency and quality using a computer‐assisted semen analyzer

Straws of sex‐sorted sperm are usually packaged at a low concentration (e.g., ~2.1 × 10⁶ sperm/ml) and cost significantly more than unsorted conventional semen from the same sire. In order to maximize the efficiency of using sex‐sorted sperm under in vitro fertilization conditions, the selection of an appropriate sperm separation technique is essential. In this study, the effect of using different silane‐coated silica colloid dilutions and layering configurations during centrifugation of sex‐sorted sperm was examined over an extended period of incubation time. Sperm recovery and viability after centrifugation using the colloid separation technique were measured along with several sperm motility parameters using CASA. For this purpose, frozen and thawed sex‐sorted sperm samples were centrifuged using mini‐volume single‐layer (40%, 60% and 80%) and mini‐volume two‐layer (45%/90%, 40%/80% and 30%/60%) separation configurations using PureSperm^®. A single layer of 40% PureSperm^® recovered significantly more sex‐sorted sperm (78.07% ± 2.28%) followed by a single layer of 80% PureSperm^® (68.43% ± 2.33%). The lowest sperm recovery was obtained using a two‐layer PureSperm^® dilution of 45%/90% (47.57% ± 2.33%). Single‐layer centrifugation recovered more sorted sperm (68.67% ± 1.74%) than two layer (53.74% ± 1.74%) (p < .0001). A single layer of 80% PureSperm^® exhibited the highest sorted sperm viability (72.01% ± 2.90%) after centrifugation (p < .05). The mini‐volume single layer of 80% PureSperm^® was determined to be an effective alternative to a two‐layer centrifugation configuration for sex‐sorted sperm selection. In addition, single‐layer colloid dilution of 80% performed either as well as or significantly outperformed the other treatments, as well as the control, with regard to motility (MOT) for all time periods of analysis.     

Hyperostotic polyarthropathy in a rabbit - a suspected case of chronic hypervitaminosis A from a diet of carrots

Chronic hypervitaminosis A can occur in many species after excessive dietary intake of Vitamin A (retinol). The most common presentation of chronic hypervitaminosis A is a polyarthropathy with hyperostosis and ankylosis of various joints. This case report describes a probable case of naturally occurring hypervitaminosis A-induced polyarthropathy in a rabbit after chronic ingestion of a diet made up almost exclusively of carrots. Carrots do not contain retinol, but are rich in provitamin A (or beta-carotene). Rabbits are unique in that they can convert 100% of dietary beta-carotene into retinol. A syndrome of naturally occurring hypervitaminosis A-induced polyarthropathy has not been described in a rabbit before.     

Local Effect of the Corpus Luteum on Ovarian Follicular Functional and Morphological Features in the Goat

Ovaries of unilaterally ovulated goats (n=21) were used to study follicular morphological features (proportion and degree of atresia, oestradiol production in vitro and progesterone production of granulosa cells in culture). Follicles were dissected out and classified as small (1–2 mm), medium (2–4 mm) and large (>4 mm). Morphological and physiological features were compared in each size class between ovaries bearing and not bearing corpora lutea (CLO and NCLO, respectively). Within the same size class, there was no difference in proportion or in degree of atresia, between CLO and NCLO. A significant effect of follicular size on oestradiol production in vitro was detected, but no effect of the corpus luteum was found. Finally, progesterone production of granulosa cells in culture was significantly higher in CLO than in NCLO after 24 h (p < 0.05) and also after 90 h (p < 0.01) of culture. This higher progesterone production by CLO granulosa cells in culture could be explained by local influence of the corpus luteum stimulating the steroidogenic activity but not aromatase activity. Further studies are needed to clarify possible factors and pathways for this local effect of the corpus luteum upon follicular physiology.     

Effect of lasalocid on the GnRH-induced LH and testosterone release during puberal development in the Brahman bull

To determine the effect of lasalocid on endocrine patterns associated with puberty, 12 half-sib prepuberal Brahman bulls were allotted by age and weight (174 to 256 d of age; 141 to 243 kg) to control or lasalocid treatments. Bulls in the control treatment were fed a 4:1 corn:cottonseed meal concentrate plus Coastal bermudagrass hay to which the bulls were given ad libitum access. The lasalocid treatment was identical except for the addition of 200 mg of lasalocid.animal-1.d-1. Blood samples were collected frequently before and after GnRH (200 micrograms, i.m.) on d 7, at 28-d intervals thereafter, and within 14 d after puberty (defined as 50 x 10(6) sperm cells with 10% motility). By d 7, bulls fed lasalocid released more LH (P less than .05), but not testosterone (T;P greater than .10), in response to GnRH than controls. At the time that the first sperm cells were observed in an electroejaculate (FS), lasalocid-fed bulls released more (P less than .05) LH and T than controls. At puberty, there was no difference (P greater than .10) between treatments in amount of T released, although lasalocid-fed bulls released more LH (P less than .05). Before puberty, concentrations of LH were positively correlated with concentrations of T in samples collected 1 and 2 h later. Both groups of bulls exhibited a linear increase in T response with advancing age (P less than .005). Release of LH decreased with age in the control bulls (P less than .10) but was unaffected by age in lasalocid-fed bulls. Both groups showed a decreased (P less than .001) LH:T response ratio with advancing age. Results of this study with bulls confirm previous reports in heifers of the enhancing effect of an ionophore on reproductive function.     

Characterisation of porcine haemophili isolated from Australian pigs between 1988 and 1992

SUMMARY A total of 362 haemophili, isolated from pigs throughout Australia, were characterised by phenotypic properties. Most were identified as Actinobacillus pleuropneumoniae (296 isolates) or Haemophilus parasuis (52 isolates). The remaining isolates were identified as Haemophilus Taxon ‘minor group’ (12 isolates) and Haemophilus Taxon D (two isolates). All 296 A pleuropneumoniae isolates were serotyped by slide agglutination and/or gel diffusion, using rabbit antisera against all 12 recognised serovars. Of these, only 156 (52.7%) could be assigned to a single serovar as follows: serovar 1–85 isolates, serovar 2–4 isolates, serovar 3–2 isolates, serovar 5–10 isolates, serovar 7–51 isolates, serovar 11–2 isolates and serovar 12–2 isolates. Of the remaining 140 isolates, 91 gave cross-reactions with serovars 3 and 6, one cross-reacted with serovars 9 and 10, one cross-reacted with serovars 9 and 11 whereas 47 gave no reaction with any of the antisera.     

Comparison of methods for the sampling and isolation of toxigenic Pasteurella multocida from the nasal cavity of pigs

The efficacy of detecting toxigenic Pasteurella multocida from nasal swabs of slaughtered and live pigs was assessed. The isolation of toxigenic P multocida from nasal cavities of slaughtered bacon pigs from two herds with atrophic rhinitis was reduced by immersion in the hot water tank by 25 per cent and 75 per cent. Individual sows from one of the infected herds were repeatedly swabbed to find the best method of isolating toxigenic P multocida. Toxigenic P multocida were isolated from 50 per cent of cotton swabs inoculated on to selective medium the same day. After 24 hours in the post, 45 per cent of cotton swabs placed in transport medium, 38 per cent of alginate swabs dissolved in transport medium and inoculated into mice, and 36 per cent of the dissolved swabs inoculated directly on to selective medium yielded toxigenic P multocida. These bacteria were isolated from only 25 per cent of cotton swabs held in transport medium at 10 degrees C for 48 hours to simulate prolonged postage times; from slaughtered pigs a similar reduction in isolation was seen with swabs kept for 24 or 48 hours. The reduced isolation caused by a delay before culture was associated with an overgrowth of other flora. The development of this flora was prevented by storage of swabs at 4 degrees C in the laboratory or by the use of cool boxes for postage.