Effects of Egg Yolk and Cooling Rate on the Survival of Refrigerated Red Deer (Cervus elaphus hispanicus) Epididymal Spermatozoa

Egg yolk is a common component to sperm refrigeration for most of the deer species, the role of which is to protect sperm membranes against cold shock. In addition, there have been many studies of conservation of ejaculated semen from stags, but few have been reported for epididymal spermatozoa. This work was designed to investigate the combined effects of cooling rates (slow: 0.23 degrees C/min vs rapid: 4.2 degrees C/min) from room temperature to 5 degrees C, and egg-yolk concentration (0, 5 or 20%) in the extender on the survival of Iberian red deer epididymal spermatozoa refrigerated at 5 degrees C. Heterospermic sperm samples were diluted to a final sperm concentration approximately 400x10(6) sperm/ml with a Tris-citrate-fructose (TCF)-egg-yolk diluent. Sperm quality was in vitro judged by microscopic assessments of individual sperm motility [sperm motility index (SMI)], and of plasma membrane (hypo-osmotic swelling test) and acrosome (NAR) integrities. Our results first showed that the presence of egg yolk in the extender significantly improves (p=0.01) the viability and sperm motility after sperm dilution. In addition, acrosome and plasma membrane integrities post-refrigeration did not differ significantly between cooling procedures; however, the SMI differed significantly between cooling procedures (slow: 46.6% vs rapid: 50.0%; p=0.01). Our results also showed that sperm quality was significantly (p<0.01) affected by the combined effects of egg-yolk concentration and cooling procedure, being rapid cooling with 20% of egg yolk the most suitable combination for epididymal sperm refrigeration. In conclusion, egg-yolk improved red deer epididymal spermatozoa characteristics after dilution. Rapid cooling protocol using TCF with 20% egg-yolk significantly improved sperm motility of red deer epididymal spermatozoa after cooling.     

Salmonella monitoring programs in Australian feed mills: a retrospective analysis

The availability of safe, commercially prepared stock feed for production animals is an important step in ensuring animal health and welfare and the safety of food animal products for human consumption. Animal feed quality assurance programs include microbiological monitoring of raw materials, mill equipment and finished feed. Over a period of 16 years, 23,963 samples for Salmonella culture and serotyping were collected from 22 stock feed mills. A multivariable generalized linear mixed model (GLMM) was used to identify mill and sample type factors that increase the odds of detecting Salmonella. The odds of detecting a Salmonella positive sample was greatest in samples from raw materials and in mills that processed restricted animal material (RAM). The percentage of positive samples ranged from 7.2% in 2003 to 2.8% in 2017. Of the 1,069 positive samples, 976 were serotyped with 61 different Salmonella serotypes isolated. The serotype most frequently isolated from raw materials was S. Agona, (n = 108) whilst S. Anatum was the serotype most frequently isolated from equipment and finished feed (n = 156). The diversity of Salmonella serotypes differed between mills and different stages of the production line. Microbiological monitoring in the commercial preparation of animal feed in Australian stock feed mills guides the implementation of quality control measures and risk mitigation strategies thereby reducing the prevalence and diversity of potentially zoonotic bacteria such as Salmonella, enhancing food safety for both animal and consumer.     

Effect of treatment with an internal teat sealant at drying-off in cows wintered on forage crops in New Zealand on clinical mastitis and somatic cell counts

AIMS: To determine the impact of treatment with internal teat sealant (ITS) compared to no treatment at drying-off on the incidence of clinical mastitis (CM) during the dry period and 84 days after calving, and the prevalence of cows with somatic cell counts (SCC) ≥200,000?cells/mL at the first lactation herd test, for cows wintered on forage crops.

METHODS: In four dairy herds in the South Island of New Zealand, cows with no history of CM or individual SCC >100,000?cells/mL during the 2015–16 season were randomly assigned to treatment with ITS in each quarter (ITS group) at drying-off or no treatment (Control group). Cows were otherwise treated similarly, wintered on forage crops and transferred to pasture for calving and lactation. Cows were monitored over the dry period and for 84 days after calving, and any case of CM recorded. Individual SCC were recorded at the first herd test after calving.

RESULTS: Between drying-off and 84 days after calving 36/470 (7.7%) cows in the ITS groups and 73/442 (16.5%) cows in the Control group were diagnosed with CM (RR=0.46; 95% CI=0.26–0.73). The final multivariable logistic regression model included an interaction between treatment group and length of dry period. For a Friesian/Jersey cow, aged 4–8 years, with a dry period of 30–80 days, dried off without ITS, the probability of CM in the study period was 0.12 (95% CI=0.09–0.16), and for such a cow treated with ITS the probability was 0.07 (95% CI=0.05–0.10). For an equivalent cow, with a dry period of 81–140 days, which was untreated, the probability was 0.21 (95% CI=0.14–0.29), and for such a cow treated with ITS it was 0.05 (95% CI=0.02–0.11). At the first herd test after calving 77/383 (20.1%) cows in the Control group and 57/425 (13.4%) cows in the ITS group had SCC ≥200,000?cells/mL (RR=1.51; 95% CI=1.10–2.06).

CONCLUSIONS AND CLINICAL RELEVANCE: For these farms, treatment of cows with no history of elevated SCC or CM with ITS at drying-off halved the incidence of CM between drying-off and 84 days after calving, and reduced by 33% the proportion of cows with SCC≥200,000 at the first herd test after calving, compared with untreated cows. Treatment with ITS reduced the risk of CM proportionally more for cows with a dry period of 81–140 days than for cows with a shorter dry period.     

Osteopetrosis in a neonatal donkey

Osteopetrosis is a rare disorder characterised by a defect in osteoclastic bone resorption. This report describes osteopetrosis in a neonatal donkey that suffered a displaced tibial fracture. Radiographic examination identified generalised reduction in medullary cavity size, thickened mid‐diaphyseal cortices and conical metaphyseal bone extending toward the mid‐diaphysis of long bones. Postmortem examination identified additional fractures and brittle bones. Histologically, osteoclasts were absent in multiple bone sections. Diaphyseal cortices consisted of concentric bone lamellae with marrow tissue infiltration. Large wedges of secondary spongiosa extended from the metaphyseal growth plate. Clinical and histopathological features were similar to an osteoclast‐deficient, autosomal recessive form of osteopetrosis in humans.