Biotin and lameness in ewes

The trial was carried out in a commercial North Country Mule flock with a history of white line disease in replacement ewe lambs. During the year of study the feet of 302 animals were repeatedly scored using a categorical scoring scale. Animals with WL lesions in one or more feet (n=260) and those without lesions (n=42) were randomly allocated to one of three treatment groups in January 2012: 1) Control – no supplementation, 2) Zinc – zinc-based rumen bolus, 3) Biotin – a biotin and zinc bolus.

Sheep were managed as a single group throughout the study. At four-monthly intervals, sheep were weighed, re-bolused and individual feet scored. They were subsequently mated to lamb in March 2013. Lamb performance data from birth (March 2013) to weaning (July 2013) was assessed for ewes scanned as carrying twins.

The majority of sheep were observed with WL lesions at the start of the study (86%) and throughout the trial period although few were recorded with severe lesion scores at any assessment visit. Ewe lambs were sourced from three farms and there was some evidence that the proportion of sheep observed with white line lesions in January 2012 differed depending on their farm of origin. Regression analysis identified no significant difference (p>0.05) between the proportion or severity of WL scores recorded in Control, Zinc or Biotin groups at any of the four assessment visits. In feet observed with lesions in January 2012 (n=763) there was some reduction in the percentage of WL lesions across all three treatment groups, although significant treatment differences were not observed.

Similarly an analysis of feet with no lesions present (score 0) in January 2012 (n=445) looked at the proportion that subsequently developed lesions (Score 1-5). Treatment differences were not observed at any sampling date with 25 – 30% being observed with lesions by the end of the study. An analysis of the foot data for 42 sheep that were lesion free at the start highlighted that by January 2013 just under half (48%) had retained their lesion-free status throughout the whole study period and these were evenly distributed across the treatment groups.

Analysis of live weight and live-weight gain data for study ewes confirmed that there were no treatment effects on ewe performance at any point during the study.

Twin-bearing ewes lambed indoors from 27th February 2013 and at birth lambs averaged 4.4 kg with weights being similar for all treatments. All lambs were creep fed. Lambs were weighed in May at 10 weeks of age and prior to weaning in July 2013. Lambs from ewes supplemented with biotin were significantly heavier at 10 weeks of age (23.7 kg) than Zinc (22.3 kg) or Control (21.8 kg) lambs (p=0.002) and
had significantly higher growth rates (269, 251 and 245 g/d respectively) (p=0.003) from birth to 10 weeks.

The value of the additional live weight seen in Biotin lambs compared to Control lambs was estimated to be worth £4.60/lamb (assuming £2.42/kg lwt) at 10 weeks of age. By weaning however the advantage to the Biotin treatment had disappeared with DLWG from 10 weeks to weaning (252 g/d) and weaning weight (36.1 kg) being similar for all treatments. Greater dependence on creep feed rather than milk may explain this levelling off in performance across treatments by weaning but the results do indicate superior performance in lambs born to ewes that received biotin which is likely to have been due to higher milk yield in the first 10 weeks of lactation.

Overall there appeared to be no benefit of bolusing ewes with Biotin +- zince on foot health or ewe performance.

The Problem:

Lameness is a common problem in the UK sheep flock and causes significant loss of production and poor welfare. The recent Farm Animal Welfare Council Opinion on Lameness in Sheep (FAWC March 2011), states that further research into lameness in sheep is required and that an overall aim of reducing the national prevalence of lameness from around 10% to 5 % should be achieved within 5 years.  A longer term aim of reducing prevalence to 2% or less should be achievable within 10 years.

In 80% of flocks, foot rot and scald (interdigital dermatitis with or without under-running separation of hoof horn from the underlying sensitive tissue) are the most common causes of lameness accounting for approximately 90% of foot lameness in the national flock. However white line disease (or shelly hoof) is common in many flocks and poor hoof integrity may be a precursor to other infections including foot rot.

Aims and Objectives:

Aims

• To investigate if ewes supplemented with biotin have improved hoof health and fewer cases of lameness

Deliverables

• The results will be disseminated to the industry and incorporated into the BRP lameness manual.

Approach:

A farm with history of lameness problems will be recruited.  200 sheep with and without white line lesions (100 with white line lesions and 100 sound sheep) will be selected. 50 lame and 50 sound ewes will be given a biotin bolus, while the others will receive a bolus with no biotin (control). All feet will be scored by a vet, and any problems will be treated to best practice standards.  The ewes on trial will be run with the rest of the flock.  Lameness will be monitored and treatments recorded.  The vet will return every 3 months to re-score the ewes‘ feet.