Antibiotic use is a topical subject. There is increasing concern about possible antimicrobial resistance and a commitment by the agriculture industry to reduce the amount of antibiotics used. Much of the media attention is focussed on human health but we also have a duty to preserve the effectiveness of treatments for animals under our care. There have been a few cases in the UK of fatal E.coli infections in new born lambs that are resistant to multiple antibiotics. Attention to basic principles and preventive medicine promotes responsible antibiotic use.
There is no single solution to reduce the use of antibiotics in animals. Antimicrobial resistance risk must be reduced through a number of measures. Work is underway on a Farming Connect Demonstration Site to reduce the use of antibiotics at lambing time. Closely monitoring ewe nutrition and management in late pregnancy and observing strict bio-security protocols at lambing should help reduce the use of antibiotics as a precautionary measure, encouraging more responsible use of medicines and offering significant cost savings.
The main uses of antibiotics in sheep flocks are for abortion outbreaks, lameness and at lambing (particularly in new born lambs).
The ewes at Plas are all vaccinated against Enzootic abortion and Toxoplasmosis so Enzootic abortion of ewes (the infection that is treated with antibiotics in an outbreak) is not a problem. The flock are also vaccinated against footrot and the booster timing was slightly altered this year to 3 to 4 weeks pre housing so the best effects were over the housing period. The extra attention to hygiene with lime used under fresh straw and the main pens being cleaned out between batches of ewes will have reduced footrot bugs as well as others that may affect lambs. There have been very few lame ewes, another bonus and one that affects body condition and milk production.
The flock of 1,100 Suffolk cross ewes and 350 mule type ewes at Plas, Llandegfan, Anglesey started lambing in the middle of January, with ewe lambs lambing from mid-March onwards. Previous outbreaks of Joint Ill, Watery Mouth and Coccidiosis meant use of oral antibiotics in newborn lambs was common on the farm, contributing to a significant vet and medicine cost. In order to try to eliminate this practice, the project began by focusing on ewe management. Having an active Animal Health Plan has allowed the farm to measure their usage of antibiotics and take measures to reduce usage.
Farmer Arwyn Jones always has his forage analysed and then formulates a ration accordingly. This year the ewes were also blood sampled three weeks before lambing and a metabolic profile created. The metabolic profile gives a more detailed insight into the ewe’s condition, measuring levels of energy, protein and minerals and enables adjustment of the diet prior to lambing. The metabolic profiles showed that the twin ewes were a little short of energy, which could lead to negative energy balance. Sheep in negative energy balance try to use body fat as an energy source and can develop pregnancy toxaemia (also known as twin lamb disease) due to the combination of low blood glucose and the toxic effects of the ketone bodies produced by fat breakdown. To avoid this, the concentrate in the ration - which would normally have been increased to 600g per day - was stepped up to 720g per day. Metabolic profiles of the last group to lamb showed good levels of energy and protein so adjustments were not needed providing confidence that the colostrum quality would be good.
According to independent veterinary surgeon and sheep consultant Kate Hovers working on this project at Plas,
“Nutrition is vital for producing good quality and quantity of colostrum, which contains antibodies that help prevent infection. Sufficient intake in the first few hours after birth is essential for performance, leading to heavier weaning weights and fewer days to finishing.”
To monitor colostrum absorption, blood samples were taken from 12 lambs in the first group and 42 in the last ewe group at 2 days old. They were tested for levels of immunoglobulin, which is an indication of the quality and volume of colostrum absorbed. The lambs will then be monitored for daily liveweight gain and worm burdens until they are sold as finished lambs. All lambs in the first group showed good levels of immunoglobulins and all but 3 in the second group. Two of the three lower levels were lambs that were considered at risk (small and slow to suck, sick ewe). Colostrum from the dams of these lambs was also measured on the farm using a Brix Refractometer. This is a simple device usually used in jam making, 2 or 3 drops of colostrum are dropped onto a plate then a reading is taken off a scale when looking down the eye piece. These are used by some dairy farmers to assess colostrum quality for their calves and a few sheep farmers have started trying in the sheep shed. While it would be impractical to test all ewes it is relatively simple to test a few ewes from different groups at lambing to give a guide to average levels and maybe give confidence that all lambs should not need antibiotics and they can be concentrated on higher risk individuals. The same applies to blood sampling lambs to check for protein in the blood as a guide to immunoglobulins from colostrum uptake. Sampling a few lambs, particularly multiples early in lambing can give confidence all is good or ring alarm bells to investigate before problems arise.
Observing strict hygiene protocols is another aspect of the project that also aims to reduce the routine use of antibiotics. The lambing sheds now have hand wash facilities with hot water, which is an area often overlooked although disease can quickly build up on hands, clothes and boots. Some individual pens have been set in a separate block for any aborting or sick ewes or sick lambs. Pens that have housed sick lambs will not be used again until after a complete clean out, wash and disinfection. Ewes and lambs go from individual pens to large nursery pens before turn out. These have been cleaned out between batches this year as have the main lambing pens. The sheds at Plas are traditional buildings but accessible to clean by tractor which took approximately 20 minutes before bedding down for the next batch.
The first 500 lambs born at Plas had no antibiotics, there was one case of watery mouth and one joint ill. Some antibiotics will be used in later lambs, targeted at higher risk lambs which are not so vigorous at birth, low or high birth weight (below 3.5kg or over 6kg) and poorer ewes or sick ewes.
The results, costs and savings will be analysed to see the impact of this new regime and to see where further improvements can be made.
For further information on all Farming Connect demonstration network projects please click here.