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.     

Selection of red deer spermatozoa with different cryoresistance using density gradients

The objective of sperm selection media is selecting the best spermatozoa and to remove seminal plasma and diluent for using them in assisted reproductive techniques. It is known that individuals show different cryoresistance in response to the same freezing procedure. Our hypothesis was that the efficacy of selection media could be dissimilar for samples with different sperm quality after thawing. Epididymal sperm samples from mature Iberian red deer were collected and frozen. Males were classified as with high post‐thaw sperm quality when sperm motility (SM) ≥ 70%, or as with low post‐thaw sperm quality when SM ≤ 69%. Samples were centrifuged using the following density gradients (DG): Percoll^®, Puresperm^® and Bovipure^?, and several functional sperm parameters were assessed after sperm selecting and washing. Males classified with high sperm quality had higher post‐thawing values (p > .05) for all parameters evaluated, except for linearity index, than those categorized as low sperm quality. After selection, some sperm characteristics improved (viability, apoptosis and mitochondrial activity) for both groups, showing the males with high sperm quality higher values in all sperm parameters except for kinematic traits and DNA fragmentation index (%DFI), regardless of DG. Bovipure^? yield lower values of sperm motility, viability, apoptosis and mitochondrial activity in relation to Percoll^® and Puresperm^® considering both quality groups. There was an interaction between the type of DG and sperm quality group for sperm viability (p = .040) and apoptosis (p = .003). Thus, Percoll^® selected less live and more apoptotic spermatozoa than Puresperm^® and Bovipure^? for males with low sperm quality. In conclusion, the DG are more efficient selecting spermatozoa from samples with high sperm quality, acting differently depending on initial sperm quality.     

不同Rht基因在冬小麦育种中的利弊分析

利用携带不同的Ｒｈｔ矮秆基因的６个冬小麦近等基因系,进行了两年试验,研究了不同矮秆基因在育种中的利用价值,结果表明,Ｒｈｔ１和Ｒｈｔ２两个半矮秆基因提高了单株（或单穗）粒数和粒重,经济系数和倒二叶面积。产Ｒｈｔ３和高秆系显著降低了千粒重,Ｒｈｔ３矮秆基因对单株粒数,单株产量和穗粒数均负向作用,显著提高了千粒重;Ｒｈｔ１＋Ｒｈｔ２较高秆系和Ｒｈｔ２＋Ｒｈｔ３系比较显著提高了经济系数,Ｒｈｔ２＋Ｒｈ５     

Effect of reducing inspired oxygen concentration on oxygenation parameters during general anaesthesia in horses in lateral or dorsal recumbency

Objective

To compare the effects of two concentrations of oxygen delivered to the anaesthetic breathing circuit on oxygenation in mechanically ventilated horses anaesthetised with isoflurane and positioned in dorsal or lateral recumbency.

Methods

Selected respiratory parameters and blood lactate were measured and oxygenation indices calculated, before and during general anaesthesia, in 24 laterally or dorsally recumbent horses. Horses were randomly assigned to receive 100% or 60% oxygen during anaesthesia. All horses were anaesthetised using the same protocol and intermittent positive pressure ventilation (IPPV) was commenced immediately following anaesthetic induction and endotracheal intubation. Arterial blood gas analysis was performed and oxygenation indices calculated before premedication, immediately after induction, at 10 and 45 min after the commencement of mechanical ventilation, and in recovery.

Results

During anaesthesia, the arterial partial pressure of oxygen was adequate in all horses, regardless of position of recumbency or the concentration of oxygen provided. At 10 and 45 min after commencing IPPV, the arterial partial pressure of oxygen was lower in horses in dorsal recumbency compared with those in lateral recumbency, irrespective of the concentration of oxygen supplied. Based on oxygenation indices, pulmonary function during general anaesthesia in horses placed in dorsal recumbency was more compromised than in horses in lateral recumbency, irrespective of the concentration of oxygen provided.

Conclusion

During general anaesthesia, using oxygen at a concentration of 60% instead of 100% maintains adequate arterial oxygenation in horses in dorsal or lateral recumbency. However, it will not reduce pulmonary function abnormalities induced by anaesthesia and recumbency.     

Infection of pigs with transmissible gastroenteritis virus from contaminated carcases

Sixteen 6-month-old pigs were exposed to transmissible gastroenteritis (TGE) virus by placing them in close contact with piglets infected at 1 week of age. Fourteen of the older pigs were slaughtered between 1 and 5 d after exposure to infection and their carcases dressed in simulated abattoir conditions. Samples of muscle, bone marrow and carcase lymph nodes were stored at -25 degrees C for at least 30 d and then homogenised and fed to groups of 1-week-old and 3-week-old pigs. Four of 12 one-week-old pigs died and TGE virus was isolated from intestinal contents of one of these. All pigs of both age groups developed neutralising antibody to TGE virus over the ensuing 4 w. The results indicate that carcases from pigs infected with TGE virus can represent a source of infection for susceptible pigs given access to them.     

Nonsurgical management of type II fractures of the distal phalanx in 48 Standardbred horses

OBJECTIVE: To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses. DESIGN: Retrospective study of 48 affected horses. RESULTS: Most fractures occurred on the lateral palmar process of the left forelimb or the medial palmar process of the right forelimb; 81% of horses were considered sound enough to return to training and 63% raced. Of those returning to racing, 41% competed in > 10 races, 37% in 2 to 10 races and 22% in only 1 race. There was no difference in performance before and after fracture. Twenty-four of 25 horses had a bar shoe fitted for > 50% of the treatment phase. Of those horses returning to training without a bar shoe, 89% refractured at the same site. Sixty percent of horses returning to training with a bar shoe raced successfully. The total convalescent time, the time rested in a box and the time spelled in a paddock were similar for horses returning to racing and those that did not. The age of the horse had no effect on the ability to return to racing. CONCLUSION: The prognosis for type II fractures of the distal phalanx is guarded. It is advisable to fit a bar shoe on the horse during convalescence. Horses returning to training and racing with a bar shoe appear less likely to refracture the distal phalanx. Those horses that return to racing can perform at a level similar to that prior to fracture.