Prevalence of Mycoplasma bovis Infection in Calves and Dairy Cows in Western Australia.

Mycoplasma bovis (M. bovis) can cause a multitude of diseases in cattle, with detrimental effects on the farm economy and the welfare of both adult and young cattle. The objective of this study was to determine the prevalence of M. bovis in adult cows and calves in the south-west region of Western Australia. A cross-sectional study was conducted on 29 dairy farms with 699 apparently healthy adult lactating cows and 495 young calves during 2019-2020. Nasal swabs and blood samples collected from the animals and bulk tank milk (BTM) samples were assessed for M. bovis-specific proteins and antibodies by using polymerase chain reaction (PCR) and Mycoplasma immunogenic lipase A- Enzyme-Linked Immune Sorbent Assay (MilA ELISA). A seroprevalence of 42.5% (95% CI: 38.9-46.2) and 61% (95% CI: 56.6-65.2) was found in adult lactating cows and calves, respectively. The herd-level seroprevalence of M. bovis ranged from 4% (95% CI: 07-19.5) to 92% (95% CI: 75.0-97.8) in adult lactating cows and 25% (95% CI: 10.2-49.5) to 87% (95% CI: 67.9-95.5) for calves in these farms. None of the BTM and nasal swab samples were positive for M. bovis, indicating an absence of any current active infections on the farms. The female calves and pure Holstein-Friesian animals are twice as likely to be seropositive for M. bovis compared to male calves (OR 2.4; 95% CI: 1.7-3.5) and Holstein-Friesian crossbred calves (OR 2.4; 95% CI: 1.7-3.5). The high seroprevalence in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms.

Characterization of metabolic and inflammatory profiles of transition dairy cows fed an energy-restricted diet.

Periparturient diseases of dairy cows are caused by disproportionate energy metabolism, mineral imbalance, and perturbed immune function. The aim of the present study was to characterize metabolism, innate immune endometrial gene expression, and uterine microbial populations of transition animals receiving normal or restricted energy diets. Pregnant multiparous Holstein cows (n = 14) were randomly assigned to one of the two dietary treatments from 20 d prepartum until 35 d postpartum (DPP). One group was fed a diet providing 100% energy requirements (NE), whereas the other received an energy-restricted diet providing 80% energy requirements (RE). Feed intake, milk yield, body weight, body condition score, temperature, respiratory, and pulse rate were recorded. After calving, blood was collected weekly to analyze nonesterified fatty acids (NEFAs), ß-hydroxybutyrate (BHB), and total cholesterol (TC). Endometrial cytobrushes were collected for gene expression analysis of inflammatory markers, microbial populations determination, and cytological evaluation. The restricted energy diet did not alter feed intake or milk yield but changed energy balance and metabolites levels (P < 0.05). In fact, RE animals had high NEFA and BHB levels, and low TC concentrations (P < 0.05). Moreover, RE animals had upregulated gene expression of serum amyloid A3 (SAA3) at 35 DPP (P < 0.05) and CXC chemokine receptor 2 (CXCR2) at 14 DPP (P < 0.01). Interleukin (IL) 1 and IL8 genes were downregulated 14 DPP but upregulated 35 DPP in RE animals, whereas IL6 and lipopolysaccharide-binding protein (LBP) genes were upregulated at 14 DPP (P ≤ 0.05). The most abundant phyla in RE animals (n = 3) were Bacteroidetes and Fusobacteria, whereas Proteobacteria was the least abundant at both 14 and 35 DPP. In conclusion, it can be speculated that energy balance is one of the main drivers for uterine inflammation by affecting metabolism, immune function, and uterine microbiota. However, these findings should be validated in a larger sample size.

Beliefs, Attitudes and Self-Efficacy of Australian Veterinary Students Regarding One Health and Zoonosis Management.

This study aimed to explore the beliefs and attitudes of a group of senior veterinary students regarding One Health and to evaluate their levels of confidence in advising the general public on preventative health issues at the human-animal interface. An online survey was communicated to senior veterinary students who were in their last two years of study. The questionnaire covered beliefs and attitudes, issues concerning the animal-human interface and participants' confidence in diagnosing zoonoses. In total, 175 students from five Australian veterinary schools/colleges completed the online survey. The majority (96%) of students considered it their duty to promote the One Health approach, but only 36% believed there were sufficient practical frameworks for Australian veterinarian graduates to promote One Health. Interestingly, 81% (142/175) of respondents believed that veterinarians were more knowledgeable than physicians in managing zoonotic cases. Of the final-year students (n = 77), only 39% and 36% were confident in their ability to diagnose zoonoses in common companion animals and production animals, respectively. However, the number of those confident to diagnose zoonoses transmitted from wildlife was notably lower (22% (17/77)). Next-generation Australian veterinarians are keen to embrace their role in interprofessional collaboration; however, training efforts are required to reassure future veterinarians on aspects of zoonoses and One Health.

Comparative aspects of immunity and vaccination in human and bovine trichomoniasis: a review.

Trichomonas vaginalis and Tritrichomonas foetus are important extracellular protozoans that cause, respectively, human and bovine venereal diseases. Trichomonads are extracellular parasites that primarily inhabit the genital tracts of the mammalian hosts where they overcome the mucus barrier and parasitize mucosa by contact-dependent or contact-independent cytotoxicity. Transient immunity is usually achieved by the host after clinical infection. At present, vaccination in cattle reduces infection rates and reproductive wastage in affected herds. After vaccination, immunoglobulin G (IgG) levels increase in systemic circulation while immunoglobulin A (IgA) levels rise in the vagina. Only moderate protection is conferred by means of vaccination. Future vaccine development strategies are needed for cattle to enhance the antigenic component or use adjuvant that strongly activates the innate immune response to produce safe and potent vaccines. This paper reviews the current knowledge of the immunology of trichomoniasis infection and the challenges and potential of vaccines in the control of the infection in human and bovine trichomoniasis.

Interactions between negative energy balance, metabolic diseases, uterine health and immune response in transition dairy cows.

The biological cycles of milk production and reproduction determine dairying profitability thus making management decisions dynamic and time-dependent. Diseases also negatively impact on net earnings of a dairy enterprise. Transition cows in particular face the challenge of negative energy balance (NEB) and/or disproportional energy metabolism (fatty liver, ketosis, subacute, acute ruminal acidosis); disturbed mineral utilization (milk fever, sub-clinical hypocalcemia); and perturbed immune function (retained placenta, metritis, mastitis). Consequently NEB and reduced dry matter intake are aggravated. The combined effects of all these challenges are reduced fertility and milk production resulting in diminishing profits. Risk factors such as NEB, inflammation and impairment of the immune response are highly cause-and-effect related. Thus, managing cows during the transition period should be geared toward reducing NEB or feeding specially formulated diets to improve immunity. Given that all cows experience a reduced feed intake and body condition, infection and inflammation of the uterus after calving, there is a need for further research on the immunology of transition dairy cows. Integrative approaches at the molecular, cellular and animal level may unravel the complex interactions between disturbed metabolism and immune function that predispose cows to periparturient diseases.