June 2023
Mastitis in ewes: culling selection
Mastitis is a common issue in sheep during and after the lambing season, and also around weaning. Research has shown that lambs from ewes with udder problems are 2-3 times more likely to die, and average 2 kg lighter at weaning.
The timing of your udder examination is important as you may cull the wrong ewe, 4-6 weeks post-weaning is ideal. You are looking for hardness in one or two quarters as well as lumps in their udder. Check each half by feeling it. Roll the teats between your fingers. Don’t rely on a visual inspection at shearing
You should cull ewes with:
Udder:
Hardness in one or two sides
Various size lumps
Signs of a burst abscess
Teat:
Hard core in the middle when rolled between your fingers
Missing or very damaged teats
When not to cull ewes:
Lumps just in front of, or just behind the udder but not in the udder tissue.
Slight abrasions and scarring on teats
Flock incidence of clinical mastitis ranges from 0–6.6 per cent per year. It is a contagious disease and one case increases the risk for the rest of the flock. More than 30 bacterial species have been isolated from sheep milk.
Risk factors for mastitis are:
Underfeeding protein and energy in pregnancy and lactation
Low body condition score (BCS) at lambing
Poor hygiene at lambing time will allow environmental bacteria to multiply, which increases the chance of infection
Ewes of any age rearing two or more lambs
Ewes and lambs that stay indoors longer
Good udder conformation is associated with decreased risk of mastitis. Although knowledge has increased, there is still no effective control strategy to prevent mastitis. The recommended treatment is injectable antibiotics (not cow mastitis tubes as they can damage the teat canal) and anti-inflammatory medicines given as soon as possible. It is unlikely that any one vaccine will prevent mastitis. Focus on hygiene, nutrition and prevention of spread will always be critical for control.
Fly Control
With cases of blowfly strike already being reported in the area it is worthwhile ensuring you have an adequate fly control policy in place. Flies can lead to serious welfare concerns by making cattle or sheep uncomfortable, spreading disease such as infectious conjunctivitis (Pink Eye) or summer mastitis in cattle and causing blowfly strike.
Flies impact growth rates with a loss up to 0.3kg/day in cattle and up to 5.5kg bodyweight loss in sheep in just 4-6 days.
Measures to reduce the reproductive opportunities for the flies include homemade fly traps, swift removal and disposal of carcases, ensuring sheds are kept clean through regular mucking out and maintaining muck stores away from livestock. Ensuring lame sheep are promptly treated and avoiding routine tasks that will cause wounds such as castration or disbudding in the warmer weather will help reduce attractiveness to flies. Good parasite control and timely shearing will reduce faecal soiling of fleeces. Any animals suffering from diseases spread or caused by flies should be housed to help reduce the spread of infection to other animals in the group.
Preventative treatments should be applied early in the season to reduce reproductive opportunities for the flies and reduce the risk of infection spread between animals. Options for cattle include medicated ear tags and pour-on treatments, remembering that the pour-ons require repeated applications. For sheep, short and long acting topical sprays are available, and dipping can also be used. Please speak to one of our vets if you would like to discuss your fly control policy.