The reversal of xylazine/ketamine immobilisation of fallow deer with yohimbine

Fallow deer were immobilised using a combination of xylazine and ketamine. Adult males (n = 10) and adult females (n = 10) received 4 mg/kg of each drug intramuscularly. Juveniles (n = 11) received 2 mg/kg of each drug, intravenously. Times to recumbency were as follows: adult males 4.9 +/- 2.9 min, adult females 4.1 +/- 1.9 min, juveniles 2.3 +/- 1.1 min. After 30 min each deer received 0.2 mg/kg of yohimbine, or an equal volume of sterile diluent intravenously. Yohimbine substantially reduced the recovery times of treated deer. Adults males were releasable 7.2 +/- 4.3 min after yohimbine administration, whereas control males were not releasable until 165 +/- 18 min. Treated adult females were releasable after 6.6 +/- 4.3 min, while control females were not releasable until 84 +/- 29 min. Juveniles were releasable 2.1 +/- 0.8 min after administration of yohimbine but control juveniles were not releasable until 62 +/- 16 min. Xylazine/ketamine administration produced statistically significant changes in packed cell volume, total plasma protein, albumin, sodium, glucose, creatine phosphokinase and inorganic phosphate values after 30 min. Yohimbine administration had no effect on these changes.     

Electrolytes Changes in Mammary Secretions Before Foaling in Jennies

No knowledge regarding the peripartum changes in mammary secretions in the jenny are presently available in literature. In the mare, instead, several studies report the role of these changes as indicators of foetal readiness for birth and impending parturition. This experiment was designed to determine calcium, sodium, potassium concentrations, and the value of sodium/potassium ratio in mammary fluids during prepartum in the jenny. Samples were daily collected by hand milking, after mammary gland size increased noticeably, from 17 Martina Franca jennies. Prepartum mammary secretions were analysed every other day between day 10 and day 2 antepartum, and then once a day from the day before to the day of parturition. Calcium concentration showed a significant increase between day 10 and day 6 antepartum and then between day 6 and days 4 and 2. Afterwards, another statistical significant increase was observed at parturition. Sodium concentration significantly decreased from day 10 to day 2 prepartum. Potassium concentration significantly increased between day 10 and day 8 before parturition, then showed a further increase at day 4, followed by none significant changes until foaling. All jennies showed a reversal in sodium/potassium ratio between 2 days antepartum and the day before. In conclusion, the evaluation of mammary fluid calcium concentrations and the reversal of sodium/potassium ratio could be used as good indicators of foetal maturity in the jenny. As far as the prediction of parturition is concerned, the reversal of sodium/potassium ratio is the best parameter, since it was detected 48–24 h before parturition in all considered animals.     

Heterologous In Vitro Fertility Evaluation of Cryopreserved Iberian Red Deer Epididymal Spermatozoa with Zona-intact Sheep Oocytes and its Relationship with the Characteristics of Thawed Spermatozoa

A heterologous in vitro system, using zona‐intact sheep oocytes, was used to evaluate the relationship between sperm factors of Iberian red deer thawed epididymal sperm and the percentage of cleaved oocytes. Epididymal spermatozoa were recovered from six males, diluted with freezing extender and cryopreserved. After thawing sperm motility (SM) and acrosome and membrane integrities were evaluated. Again, these parameters were assessed after incubation in freezing extender at 37°C for 2 h. After cryopreservation the values for SM and acrosome and membrane integrities were high (～80, 80 and 70% respectively). However, these values significantly decreased after incubation (～59, 62 and 47% respectively). Red deer thawed epididymal sperm fertilized zona‐intact sheep oocytes, although the percentage of cleaved oocytes was low (～22%). No relationship was found between sperm parameters assessed after thawing and the percentage of cleaved oocytes. Likewise, any sperm parameter evaluated after incubation was assessed in relation to the percentage of cleaved oocytes. However, acrosome and membrane integrities were near to significance (p = 0.06 and p = 0.09 respectively). Then, we conducted a reduced model with these two variables and both were related to the percentage of cleaved oocytes (p = 0.02 and p = 0.04 respectively). Thus, acrosome and membrane integrities were related to the percentage of cleaved oocytes negatively and positively respectively. It was concluded that the classical parameters assessed in deer thawed sperm samples can be good predictors of the ability to fertilize zona‐intact sheep oocytes.     

Redox cycling induces spermptosis and necrosis in stallion spermatozoa while the hydroxyl radical (OH•) only induces spermptosis

Oxidative stress is a major factor explaining sperm dysfunction of spermatozoa surviving freezing and thawing and is also considered a major inducer of a special form of apoptosis, visible after thawing, in cryopreserved spermatozoa. To obtain further insights into the link between oxidative stress and the induction of apoptotic changes, stallion spermatozoa were induced to oxidative stress through redox cycling after exposure to 2‐methyl‐1,4‐naphthoquinone (menadione), or hydroxyl radical formation after FeSO₄ exposure. Either exposure induced significant increases (p < 0.05) in two markers of lipid peroxidation: 8‐iso‐PGF_2α and 4‐hydroxynonenal (4‐HNE). While both treatments induced changes indicative of spermptosis (caspase‐3 activation and decreased mitochondrial membrane potential) (p < 0.01), menadione induced sperm necrosis and a dramatic reduction in motility and thiol content in stallion spermatozoa. Thus, we provided evidence that oxidative stress underlies spermptosis, and thiol content is a key factor for stallion sperm function.     

Probing soil physical and biological resilience data from a broad sampling of arable farms in Scotland

Physical and biological soil stabilities (i.e. resistance and resilience) were measured on a range of arable farms across eastern Scotland under a range of management practices, with the objective of using a geographically restricted set of soils under similar land use to detect any underlying associations between soil stability, management factors and soil properties. Data were analysed using a combination of a stepwise fixed effects model selection within a linear mixed‐model framework (LMM) and neural network analysis using a Kohonen self‐organising map (KSOM). In general, physical and biological measures of stability were associated with both physical and biological soil properties, particularly bulk density, water retention characteristics, soil carbon and bacterial community structure. A strength of KSOM is its ability to fit more flexible models than the linear relationships of LMM. However, a weakness is that it does not have the ability of LMM to model the sampling design, which is likely to lead to overstating statistical significance. Consequently, KSOM identified more significant associations between soil properties and stability than LMM, while the latter identified significant associations at the between‐farm level. The high‐level land management decisions of farm type (conventional, organic, integrated), crop type or underlying soil type were not associated with stability at this regional scale, thus indicating that the effects of different management practices between farms were overridden by the soil properties on each farm. Management decisions on improving soil stability therefore need to be taken at the individual field scale.     

Practices and opinions of New Zealand beef cattle farmers towards bovine viral diarrhoea control in relation to real and perceived herd serological status

ABSTRACT

Aims: To investigate the seroprevalence of infection with bovine viral diarrhoea (BVD) virus among 75 beef herds and seroconversion in cattle during early pregnancy, and to determine the practices and opinions of farmers towards BVD control and their association with real and perceived herd serological status.

Methods: Blood samples were collected before mating in 75 beef herds across New Zealand from 15 unvaccinated heifers that had delivered their first calf that season. Serum samples were tested for BVD antibodies using ELISA individually, and after pooling samples for each farm. Animals that were antibody-negative were retested at either pregnancy diagnosis or weaning. Farmers were asked to complete a detailed survey about herd demographics, BVD testing and vaccination practices, and opinions towards national BVD control.

Results: Based on the pooled serum antibody ELISA results, there were 28/75 (37%) negative herds, 15/75 (20%) suspect herds, and 32/75 (43%) positive herds. Of 1,117 animals sampled 729 (65.3%) tested negative for BVD virus antibodies; when retested, 47/589 (8.0%) animals from 13/55 (24%) herds had seroconverted. Among 71 famers providing survey responses 11 (15%) believed their herd was infected with BVD, 24 (34%) were unsure and 36 (51%) did not think their herd was infected. Only 19/71 (18%) farmers had performed any BVD testing within the past 5 years and 50/70 (71%) had not vaccinated any cattle for BVD. Support for national BVD eradication programme was strong in 51/71 (56%) respondents, but the biggest challenge to BVD control was considered to be famer compliance. Compared to farmers who did not think their herd was infected, more farmers who thought BVD was present in their herds had previously tested for BVD, would consider testing all replacement calves, and would support establishing a national BVD database; fewer would consider purchasing BVD tested or vaccinated cattle only.

Conclusions and clinical relevance: Only 15% of the beef farmers in this study believed their herds were infected with BVD virus and few of them had undertaken BVD screening. Nevertheless many were supportive of implementing a national BVD control programme. It is likely that the lack of farmer awareness around BVD and the failure of farmers to recognise the potential impacts in their herds are hindering progress in controlling the disease in New Zealand. There are opportunities for New Zealand veterinarians to be more proactive in helping beef farmers explore BVD management options.