The transition period in cows is a critical time for herds in Ireland aiming to avoid clinical disease in early lactation.
Milk somatic cell count (SCC) levels above 100,000 mean you are losing money. On average, mastitis costs farmers €60/cow/year. The major loss for high cell count is milk yield and milk quality penalties.
Subclinical mineral deficiency can adversely affect immunity in Irish herds leading to increased levels of transition diseases like mastitis. Addressing this issue could improve herd health nationally.
Years of research has documented how trace minerals are vital for disease prevention in cattle. Animals that are in poor mineral status may have poorer immunity.
Reduced zinc (Zn) levels have been linked to increased SCC; copper (Cu) deficiency causes a decrease in the resistance to diseases; Zn and selenium (Se) deficiency has been shown to impair immune response; and manganese (Mn) deficiency can result in reduced enzyme levels increasing the risk of cellular damage.
Subclinical disease is illness that is staying below the surface of detection, meaning there are no recognisable signs but the disease can still be adversely affecting the cow.
With subclinical mineral deficiency, cows may appear healthy but reproduction performance and immunity may be impacted meaning increased diseases like mastitis during the transition period.
Trace minerals are vital for udder health in dairy cows, but in Ireland herd cases of trace mineral deficiency arise frequently but are often not reported.
Rogers and Murphy in 2000 found that within Irish grass silages, 63% are low in Cu, 69% are very low in Se and 29% are low in Zn. This means a lot of cattle are on the threshold of subclinical deficiency as they are not offered silage with adequate minerals.
Furthermore, even cattle fed adequate oral mineral requirements may simply not eat enough under times of stress. In the pre-calving period, dry matter intake falls by 30-35% meaning cows do not take in enough trace minerals orally.
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Adequate trace mineral levels in cows is essential to prevent mastitis and raised SCC, but decreased food intake means cows need to use up their mineral reserve stores e.g. from the liver pre calving.
Pre-calving mineral status
In the weeks coming up to calving, the unborn calf is growing rapidly and its only supply of minerals is across the placenta from the dam.
Unfortunately, during this period there can be an increase in excretion of minerals which can be made worse by stress, but there is also a massive increase in demand for minerals.
All these processes mean there is a huge spike in mineral demand while intake is reduced, meaning mineral stores of cows can become depleted.
This is how even seemingly well-fed cows and herds can fall into subclinical mineral deficiency and fail to fight off infections in the transition period.
Other issues complicate the situation further at this time. Oral minerals are poorly absorbed by cattle.
Only 1-5% of oral Cu is absorbed by adult cattle, for Zn 10-20% and Mn only about 1% is absorbed. Therefore, even using silage that has adequate minerals can take weeks to months to build back up the mineral store in cattle.
Rumen antagonism and low oral absorption
Rumen antagonism further hampers mineral absorption.
Antagonists are minerals like sulphur (S), calcium (Ca), iron (Fe) and molybdenum (Mo), that despite being essential parts of the bovine diet, when supplied above certain levels, they adversely affect the absorption of other minerals like Cu, Zn, Mn or Se.
This means that even though diets appear to have adequate levels of trace minerals, they may not be effective in maintaining cows’ mineral levels, as the antagonists are blocking the minerals being absorbed.
Cook and Green in 2010 reported treatment of trace mineral boluses at dry-off to dairy cattle showed an unreliable trace mineral release. In some situations, they can be regurgitated and lost or, within the rumen, they can become coated with a deposit of calcium phosphate and fail to dissolve properly.
Oral supplements like drenches and boluses are subject to poor oral absorption and antagonism and thus may not effectively improve trace mineral status pre calving.
Preventing trace mineral deficiency
Strategic trace mineral injections bypass the harsh rumen environment and antagonists, rapidly raise circulating mineral levels in cows within eight-to-10 hours, and after 24 hours, the key minerals are at raised concentrations in the vital storage organs like the liver.
From here, the minerals can be incorporated into the different body systems to help maintain immunity, fertility and performance.
Strategic trace mineral injections are a fast and effective way for farmers to enhance their cows’ mineral status in the pre calving window.
Strategic trace mineral injections are a popular way to improve herd performance in the US, Australia, South Africa and New Zealand. Strategic trace mineral injections could help to improve the disease status and transition cow performance in your herd.
Years of research from leading animal health and veterinary universities from around the world have demonstrated the potential benefits of strategic mineral injections at key points of demand in the production cycle.
Teagasc speculates that in Ireland the incidence of mastitis is approximately 25%/year, costing approximately €20 million for the national dairy herd.
Pre-calving supplementation by injection helps to raise not only the trace minerals, but also the essential enzyme levels rapidly and effectively, which could help farmers reduce mastitis in their herds.
Several studies have researched the potential benefits of injectable trace mineral supplementation in cows in the transition period, with improvements in clinical mastitis, cell counts and uterine disease.
Ask your vet how an injectable trace mineral supplement could help improve transition performance in your herd.
Further Information
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References available from Virbac on request.
