Effect of Farm Management Practices on Morbidity and Antibiotic Usage on Calf Rearing Farms.

Antimicrobial resistance has been recognized as one of the top health threats to human society. Abundant use of antibiotics in both humans and animals has led to ever-increasing antibiotic resistance in bacteria. In food production, decreasing morbidity in beef herds would be an effective way to reduce the use of antibiotics. The objective of this retrospective observational study was to determine overall morbidity on calf rearing farms and to identify associated risk factors. Data were collected by questionnaire, meat companies' databases and the national cattle register for 28,228 calves transported to 87 calf rearing farms. All medications given to these calves were retrospectively followed for 180 days from calf arrival to the farm. In total, 34,532 parenteral antibiotic medications were administered to the 28,228 study calves (122.3%), and 17,180 calves (60.9%) were medicated with antibiotics at least once during the follow-up. Higher numbers of calves transported to the same farm and larger age variation in calves in the same arrival batch were both associated with increased morbidity. In contrast, higher arrival age of individual calves was associated with decreased morbidity. Our study identifies several factors to consider in decreasing morbidity and antibiotic usage on calf rearing farms.

Effect of farm and animal-level factors on youngstock mortality and growth on calf rearing farms.

Both calf mortality and daily weight gain have a crucial impact on profitability of calf rearing farms. In addition, high calf mortality rates represent an animal welfare problem. Mortality rates on calf rearing farms have been reported in several studies in different countries, but scant data regarding daily weight gain of the calves are available. The objectives of this observational retrospective study were to determine the average mortality and daily weight gain of calves and youngstock on Finnish calf rearing farms and to identify factors associated with these production parameters. National cattle register and national herd health register databases together with meat companies' databases were used to collect weight, age, breed, medication, and origin farm data for 28 228 calves transported to the 87 calf rearing farms between 1 January and 1 October 2016. A telephone questionnaire was completed by selected farms to collect management and farm-specific data. Calves were retrospectively followed for maximum 180 days since arrival to the farm. Average arrival age of the calves were 24 days (SD 14). Average calf mortality on Finnish calf rearing farms was 4.5 %. Mortality was 5.3 % on fattening farms buying milk calves, 4.6 % on specialized calf rearing farms, and 2.5 % on fattening farms buying weaned calves. Size of the calf rearing farms varied, being smallest on fattening farms for weaned calves and largest on specialized calf rearing farms. Average daily gain of the study calves was 1.074 kg/day (SD 0.166). Multilevel mixed effects logistic and linear regression models, where herd and calf batch were used as random effects, were generated to study calf level mortality and daily gain, respectively. Activities preventing transmission of pathogens between arrival batches and different age groups of animals, including application of the all in/all out principle and proper washing and disinfection of compartments for milk feeding calves between arrival batches, were associated with lower mortality and increased daily gain. In addition, higher arrival age was associated with lower mortality during the rearing period and relatively higher arrival age of the calf, compared to other calf in a same arrival batch, was associated with higher daily gain. By contrast, increased number of individual medications during the rearing period was associated with both increased mortality and decreased daily gain. There was no significant difference in mortality between farm types. Current study highlights several factors that can be affected in future to further develop the beef production chain.

Field trial to evaluate the effect of an intranasal respiratory vaccine protocol on bovine respiratory disease incidence and growth in a commercial calf rearing unit.

BACKGROUND: Bovine respiratory disease (BRD) continues to be great challenge in calf rearing units. The urgent need to decrease the use of antibiotics and increase animal welfare in beef production has forced us to introduce new preventive methods. Vaccinations could contribute to the solution, but the high incidence of BRD already at an early age has made it difficult to introduce suitable vaccination programs. Challenge studies have shown promising results in 3-14 day old calves vaccinated with intranasal BRD vaccine, but very few field trials are available to assess the efficacy of the intranasal vaccines in field conditions. We evaluated the effect of one dose of commercial intranasal vaccination on calf mortality, daily gain, and treatment incidence for BRD in one calf rearing unit. In total, 497 calves (mean age 19 days) were included in our study, 247 of which were vaccinated at the time of arrival to the unit and 250 served as negative controls (unvaccinated). Vaccinated and unvaccinated calves were situated in separate compartments until weaning. Daily gain, treatment incidence, and mortality were recorded until the calves were transported to the finishing unit, which averaged 154.5 days from arrival. RESULTS: Average daily gain over the complete study period was 1151.9 g/day (SD 137.9) for the vaccinated calves and 1139.5 g/day (SD 135.9) for the unvaccinated calves. Intranasal vaccination combined with older arrival age (17 days or older) resulted in a higher daily gain (47.8 g/day) compared with unvaccinated calves (coef. 0.0478, p = 0.003). This association was not recorded in calves that were younger than 17 days upon arrival. Intranasal vaccination was not significantly associated either with mortality (OR 0.976, p = 0.968) or treatment incidence for BRD (OR 1.341, p = 0.120). In total, six vaccinated calves (2.43%) and six unvaccinated calves (2.40%) died during the study period. CONCLUSIONS: Vaccinating arriving calves with intranasal vaccine in the calf rearing unit did not decrease the mortality or treatment incidence for BRD, but it significantly improved the weight gain in calves transported to the unit at the age of 17 days or older.

In frame exon skipping in UBE3B is associated with developmental disorders and increased mortality in cattle.

BACKGROUND: Inherited developmental diseases can cause severe animal welfare and economic problems in dairy cattle. The use of a small number of bulls for artificial insemination (AI) carries a risk that recessive defects rapidly enrich in the population. In recent years, an increasing number of Finnish Ayrshire calves have been identified with signs of ptosis, intellectual disability, retarded growth and mortality, which constitute an inherited disorder classified as PIRM syndrome. RESULTS: We established a cohort of nine PIRM-affected calves and 38 unaffected half-siblings and performed a genome-wide association study (GWAS) to map the disease to a 700-kb region on bovine chromosome 17 (p = 1.55 × 10-9). Whole genome re-sequencing of an unaffected carrier, its affected progeny and 43 other unaffected animals from another breed identified a G > A substitution mutation at the last nucleotide of exon 23 in the ubiquitin protein ligase E3B encoding gene (UBE3B). UBE3B transcript analysis revealed in-frame exon skipping in the affected animals resulting in an altered protein lacking 40 amino acids, of which 20 are located in the conserved HECT-domain, the catalytic site of the UBE3B protein. Mutation screening in 129 Ayrshire AI bulls currently used in Finland indicated a high carrier frequency (17.1%). We also found that PIRM syndrome might be connected to the recently identified AH1 haplotype, which has a frequency of 26.1% in the United States Ayrshire population. CONCLUSION: We describe PIRM syndrome in cattle, which is associated with the mutated UBE3B gene. The bovine phenotype resembles human Kaufman oculocerebrofacial syndrome, which is also caused by mutations in UBE3B. PIRM syndrome might be connected with the recently identified AH1 haplotype, which is associated with reduced fertility in the US Ayrshire population. This study enables the development of a genetic test to efficiently reduce the high frequency of mutant UBE3B in Ayrshires, significantly improving animal health and reducing economic loss.