Age at first calving in UK Jersey cattle and its associations with first lactation 305-day milk yield, lifetime daily milk yield, calving interval and survival to second lactation.

BACKGROUND: The association between age at fist calving (AFC) and production, fertility and survivability in Jersey heifers requires evaluation and comparison with published literature on Holstein heifers. METHOD: Lactation records from 7256 pedigree Jersey heifers were grouped by AFC. Analysis comprised mixed effects multivariable regression modelling and binary logistic regression modelling. RESULTS: Increased lifetime daily yield (LDY) was significantly associated with a reduced AFC; calving UK Jersey heifers at 24 months or below is optimal. Heifers calving at 25-26 months had a significantly lower mean calving interval (391 days; 95 per cent CI 386 to 397) than those calving over 30 months (399; 95 per cent CI 394 to 405) (P=0.03). Heifers with an AFC over 30 months were less likely to survive to second lactation than those with an AFC 18-24 months. Spring calving heifers produced significantly less milk per day (9.87 kg; 95 per cent CI 9.64 to 10.1) than autumn (10.18; 95 per cent CI 9.94 to 10.41) or winter calvers (10.07; 95 per cent CI 9.84 to 10.3) (P≤0.01). Heifers that calved in the winter had a significantly shorter calving interval (389 days; 95 per cent CI 394 to 383) (P≤0.01) than heifers calved in other seasons. CONCLUSION: The impact of AFC on Jersey production, fertility and longevity traits shows a similar trend to that seen in the Holstein, potentially on a lesser scale.

Outcome of surgical treatment for umbilical swellings in bovine youngstock.

Umbilical swellings are commonly identified in calves and can be caused by hernia formation, infection of the remnants of umbilical vessels or a combination of both. Ninety-one cases with umbilical swellings were admitted to the Leahurst Farm Animal Practice (LFAP) between July 2004 and February 2012; 55 were simple hernias and 36 had associated infection. Eighty-seven cases underwent surgery of which 86 survived until discharge. Postoperative complications occurred in 65/86 animals (73 per cent). In 51 cases (81 per cent) this was classified as minor requiring no additional treatment. Placement of a prosthetic mesh was associated with a higher OR for developing severe postoperative complication when compared with those not receiving a mesh (OR=19.3; 95% CI 4.5 to 83.5). Long-term survival results were available for 49 animals, 22 of which were remaining in the herd with a median age of 1346 days (3.7 years). Of the 27 animals which had exited the herd, 16 were adult dairy cows, 7 were dairy heifers, 2 were beef animals and 2 exited at an unknown stage. Umbilical surgery in calves carries a good prognosis, although placement of a mesh increases the risk of complications occurring in the postoperative period.

Impact of footrot vaccination and antibiotic therapy on footrot and contagious ovine digital dermatitis.

Footrot and contagious ovine digital dermatitis (CODD) are common causes of foot disease of sheep in the UK. The study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a UK sheep farm affected by CODD and footrot. The sheep were randomly assigned to one of two treatment protocols. In protocol A, all sheep were given two doses of footrot vaccine (Footvax, MSD), plus targeted antibiotic therapy (long-acting amoxicillin, Betamox LA, Norbrook Pharmaceuticals) to sheep with foot lesions likely to be associated with a bacterial infection. In protocol B, the sheep only received targeted antibiotic therapy. Sheep were re-examined and foot lesions recorded five and nine weeks later. New infection rates in the footrot vaccinated group were lower compared with the vaccinated group for both CODD (18.2 per cent compared with 26.4 per cent, P=0.014) and footrot (12.55 per cent compared with 27.5 per cent, P<0.001). Recovery rates were unaffected for CODD (80.46 per cent compared with 70.97 per cent, P=0.14) but higher for footrot (92.09 per cent compared with 81.54 per cent, P=0.005) in sheep which received the vaccine. On this farm, a footrot vaccine efficacy of 62 per cent was identified against footrot and 32 per cent against CODD infection. An association between a sheep having footrot at visit 1 and subsequently acquiring CODD was identified (odds ratio [OR] 3.83, 95 per cent CI 2.61 to 5.62, P<0.001). These results suggest a role for infection with Dichelobacter nodosus in the aetiopathogenesis of CODD on this farm.

Effects of parenteral amoxicillin on recovery rates and new infection rates for contagious ovine digital dermatitis in sheep.

The present study is a randomised split-flock treatment trial, which compared the effect of foot bathing in a 1 per cent solution of chlortetracycline alone with a treatment protocol that added a single injection of a long-acting amoxicillin. Overall, the prevalence of contagious ovine digital dermatitis in the examined flock was 22 per cent, while 45.7 per cent of affected sheep had infections in two or more feet. Parenteral antibiotic treatment increased the odds of a recovery by 3.8 times (95 per cent confidence interval 1.05 to 14.0) (P=0.008). Moreover, the amoxicillin injection may also have had a preventative effect, reducing the rate of establishment of new infections from 2.5 per cent for foot bathing alone compared with 1.0 per cent with the addition of parenteral amoxicillin.