Lamb losses can have a huge impact on welfare, production and farmer morale. It can be multifactorial but also highly variable depending on the individual farm and production system.
Lamb losses can have a huge impact on welfare, production and farmer morale. It can be multifactorial but also highly variable depending on the individual farm and production system. Some of the major risk factors associated with losses are birthweight, colostrum intake (quantity and quality), dystocia, indoor versus outdoor lambing, hygiene, litter size, genetics, mis-mothering etc. Many factors can be interlinked, for instance, ewe nutrition and litter size, or low birthweight and colostrum intake. It is important to assess this every season as it may change depending on circumstances to target the areas that need improving.
Lamb mortalities are highly correlated with low lamb birthweights. The most common causes for this is poor ewe nutrition pre-lambing, litter size and ewe illness. Ewes giving birth to triplets and quads are more likely to produce smaller lambs which have less brown fat and are at a greater risk of not feeding, losing heat and becoming hypothermic. Poor ewe condition and nutrition in late pregnancy causes poor udder development, milk quality and quantity, milk let down with deprived feed intakes/ poor growth rates in lambs.
Prevention of low birthweight
A 4kg lamb should have 200 mls of colostrum in the first 2 hours of life and 800 mls in the first 24 hours.
Litter size is mainly determined by body condition at tupping and genetics. Breeds, such as Lleyn, Blue Faced/mules and Dorsets, are known for large liter sizes. Multiples need extra colostrum and are more at risk of starvation and mis- mothering, through lack of attention, teats and colostrum quantity.
Genetics play an important role influencing mortality in your flock. EBVs (Estimated Breeding Values) are values assigned to animals that predict the likely performance of offspring for various traits. They are calculated from the animals own performance and from the performance of its relatives recorded by pedigree breeders. 1 Ram EBV’s traits can be found in sales catalogues and can include:
Active decision making can start with record keeping on lambing assistance, lamb mortality (reasons) and mothering ability. You can use your records for genetics management, culling and ram selection. EBV’s are a tool that offers an opportunity of using information in conjunction with your standard ram selection.
Lambs are born with NO immunity. Colostrum is the first form of milk produced that contains antibodies (and other essential nutrients) to build up the neonate’s immune system.
Causes of low colostrum intake can be due to poor supply (amount, quality or let down) from the ewe. It can also be due to low lamb birthweights, hypothermia, mis- mothering, traumatic birthing and multiples. Colostrum supply from the ewe can be lower in volume per lamb, delayed let down and poorer quality when ewes are in low BCS and/or deficient in protein and energy in the last 4 weeks of pregnancy. Mis-mothering can delay or prevent colostrum intake due to high stocking density, disturbance during lambing, first time mothers, movements and hungry/thirsty/ill ewes. #COLOSTRUMISGOLD
The lambing season can already be tiring, but adding in lamb losses can be downright stressful and demoralising. There are many management changes you and your vet can make when you are suffering from a large amount of early lamb losses. The immediate focus may be colostrum intake, hygiene and vaccinations but there may also be a wider focus, for instance, ewe nutrition, practicing more body condition scoring and scanning your flock after tupping. These management tools will all indirectly reduce the amount of antibiotics you are using on farm. If you have any queries or would like to discuss your lambing losses, please phone the practice to speak to one of our vets.