Sheep breeding
Unsound udders cause lamb loss
Dave Jordan, Agency for Food and Fibre Sciences
Key points
- Teat and udder damage in ewes can cause reduced milk production, lamb deaths and slower growth in surviving lambs.
- Causes of teat and udder damage include shearing cuts, mastitis, abnormally large teats and blocked teats.
- Cull ewes with damaged teats and udders.
Introduction
Teat and udder damage in ewes can be an important cause of lamb deaths in Queensland. Investigations found some flocks with up to 25% of ewes with teat and udder damage in some age groups, increasing at an average 2.2% per year of age. Experiments have shown that teat and udder damage in ewes could result in up to:
- 42% less milk
- 42% lower lamb survival
- 21% slower growth in surviving lambs.
A few simple procedures can reduce the incidence of ewes with damaged teats and udders, and the subsequent adverse impacts on reproduction rates and lamb growth.
Causes of udder damage
Causes of teat and udder damage, and malfunction include shearing cuts, mastitis, abnormally large teats, and blocked teats. Newborn lambs that do not obtain milk because of attempting to suckle damaged teats rapidly lose their urge to suckle (by about six hours after birth) and subsequently die.
Shearing cuts
Shearing cuts, which later result in infection or in mechanical obstruction from scar tissue, are the main cause of damage to teats. In one study, examination of 5 452 ewes in 16 flocks in western Queensland showed that the incidence of udder damage ranged from 4-19% within flocks, with up to 25% in some age groups. Up to 10% damage was found following the weaner shearing when the teats were not as well developed. Higher incidences were found when the weaners were shorn as mixed sexes rather than in separate sex groups. On average there was a 2.2% increase in each subsequent age group.
Observations found the damage mostly occurred at shearing (especially with learner shearers) and was lessened when supervision was good, and when belly wool was not removed from immediately in front of the udder. Most damage was caused by cuts to the actual teat canal, which when healed did not let milk pass down the duct past the scar tissue. Often these healed, but non-patent, teats appeared normal to the casual observer. Close examination was necessary to reveal the extent of the damage.
Mastitis
Infection of the udder (mastitis) causes the affected side of the udder to become hard, swollen and painful, often drying up. In general there is a low incidence of mastitis in sheep, so it has little impact on rates of lamb loss.
Abnormally large teats
Abnormally large teats ('bottle teats') make it difficult for newborn lambs to commence suckling. These can be caused by the teats being 'blind', eg by having the ends cut off during shearing or crutching, or because they have wax plugs that the lamb has been unable to remove. Ewes with bottle teats are easy to recognise and can be culled.
Reducing the incidence of damaged udders
Culling of ewes with damaged udders and teats is a good management practice in flocks particularly where the incidence of damaged udders is high.
Close examination of the udder is necessary to detect damage, as small, less apparent shearing wounds can stop milk flow out of the teat. Adult ewes are best checked at shearing time when the shearer is on the long blow. The teats are then clearly visible and the shearer is not inconvenienced. Any udders with scars should be stripped to detect if the canal is blocked. All faulty ewes should be raddled and removed. Maiden ewes can be checked at classing.
The higher incidence of udder damage in ewes more than 5½ years old, together with their lower net reproductive performance, makes it beneficial to cull at 5½ to 6½ years of age.
Where there is a high incidence of udder damage in maiden ewes, culling those ewes would be beneficial. The increase in incidence with age (average 2.2% per year) thereafter is relatively low.
The high incidence of udder damage at weaner shearing can be reduced by delaying the first shearing until 12 months of age when the teats are better developed and by shearing weaners in separate sex lines.
General recommendations to reduce damage at shearing and crutching include having better supervision and instruction of shearers (especially learner shearers) so they take more care when shearing or crutching, and not taking the blade of the handpiece right through the belly wool immediately in front of the udder.
Further information
For further information contact the DPI Call Centre on 13 25 23 (Queensland residents) or (07) 3404 6999 (non-Queensland residents) between 8 am and 6 pm weekdays, or e-mail callweb@dpi.qld.gov.au.
This DPI Note is also published on the DPI's PrimeNotes CD-ROM .
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
File No: SW0022 . Created: July 1999 . Reviewed: April 2003
