The number of fully-matured lambs per ewe is the most important factor in the profitability of lamb-meat production. Methods of raising the number of lambs per litter in an artificial way - genetically or hormonal may - may not result in an increased lamb mortality. Limiting sheep mortality therefore is the first step to raise production.
Resistance
Apart from the infection risks, the resistance of the lamb plays a major role.
Lambs obtain their specific immunity through the ewe's colostrum.
Insufficient colostrum intake will make the animals more susceptible. This passive immunity will pass away in the course of about 8 weeks.
Therefore it is crucial for lambs to gradually build up their own resistance.
In the first 8 weeks lambs are vulnerable and it is therefore important to take extra care of hygiene, nutrition, health care and farm feeding practices.
If growth stays behind in the milk-feeding period, it usually cannot be compensated after weaning.
Body temperature
In case of doubt, it is recommended to check the body temperature. This normally lies between 38.5 and 39.5°C.
When the temperature is around 39.5 and 40°C it is said to be high. A temperature above 40°C is called fever.
Mortality
The lamb mortality rate in Northern Europe is approximately 13%, showing a big variation between individual farms.
Mortality amongst lambs has many causes, such as:
- infectious diseases
- factor other than infection, such as poor hygiene, nutrition, housing, improper management and breeding
In most cases a combination of the above factors has a significant impact on the mortality rate of lambs.
Three different stages can be distinguished:
1. During and immediately after birth
Almost 50% of total mortality occurs in this period. Most often due to heavy and long-lasting births and improper help.
In the first 24 hours hypothermia and dehydration are the main cause.
2. The first week after birth
Problems in the first week after birth cause about 35% of the mortality and are maily ascribed to malnutrition, overlying (smothering of calf by lying on top of it) and various infections. Often the problems are birth-related (such as infections).
3. After the first week of life
In this stage, mortality primarily is the result of various infections.
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