By Vet Diane Watson
We are aware of a reduced availability and high cost of strong iodine (10%) used for navel dressing of new-born lambs this spring.
This has arisen due to production ceasing at the main source in Chile, causing prices to quadruple. Lower iodine concentrations (often below 7%) may be available but are considered to be less effective at drying and disinfecting the navel.
Dipping the navel of a new-born lamb with strong iodine is a useful tool at preventing entry of bugs, which might cause various diseases. However, it is important to remember that most cases of joint ill and other infectious conditions are a result of bacterial invasion via the tonsils or the intestinal tract due to a heavily contaminated environment.
The most important things that farmers can do to avoid disease outbreaks and high mortality rates this lambing time are:
Ewe nutrition in the last three weeks of pregnancy has a direct impact on colostrum quality and the quantity produced, and so it is important to monitor ewe body condition and their nutrition closely.
Lambs are born with low immunity and low energy stores and so are completely dependent on good quality colostrum to provide energy and immunoglobulins/ immunity. As well as negatively impacting the quality and quantity of colostrum, under-nutrition of ewes pre-lambing delays the onset of lactation and increases the density of colostrum, which makes suckling for the lamb more difficult.
For optimum colostrum production, research shows that the ewe must have the correct balance of protein and energy in their ration. The demand for metabolisable energy and protein levels increases with ewe live weight, number of lambs carried and as lambing approaches. Metabolic profiling should be completed on sheep two to three weeks before lambing to check the ration being supplied in late pregnancy is meeting requirements.
Lambs require 50ml/kg colostrum within the first four to six hours of life and must receive the equivalent of 200ml/kg in the first 24 hours of life.
Immunoglobulins in colostrum act as the lamb’s primary immune defence against bacterial challenges, and so are important to avoid disease. After six hours of birth, the lamb’s ability to absorb the immunoglobulins into its bloodstream has reduced and after 23 hours the immunoglobulin concentration in milk has diminished, which is why it is important to get colostrum in quickly.
It is not appropriate to use tetracycline antibiotic sprays (“blue spray”) for treating the navels of new-born lambs as they do not dry them very effectively and it is an unnecessary use of antibiotics.
Similarly, it is not appropriate to use blanket systemic/oral antibiotics as a preventative to control neonatal diseases in lambs. Antibiotics should only be used if they are needed; using them as a preventative is unnecessary, a short-term solution and increases bacterial resistance on your farm.
There are registered alternatives on the market, but there is limited data available on their use in lambs. It has been shown that the speed of drying is critical to reducing infections such as joint ill and navel ill. So, when choosing alternatives, it is important to consider the drying time, the effectiveness and the safety of the product.
In summary, ensuring an adequate supply of quality colostrum through management of the body condition and nutrition of pregnant ewes, ensuring good colostrum intake and providing a clean and dry lambing environment are the most important management strategies you can implement to compensate for the low iodine supplies.