Milk Fever Farm Trial Shows Importance of Monitoring Bloods and Diet
Results from a three year EBVC trial has demonstrated that all dairy farmers could benefit from regularly testing transition cow diets for macro-minerals and monitoring fresh cow blood calcium levels as part of their milk fever prevention strategy.
Data collected by James Husband from 15 of EBVC's client's farms suggests more than half (57%) of cows are experiencing hypocalcemia (milk fever) post calving. A large proportion of these are subclinical cases which will be going undetected without blood sampling.
James says there is no way to tell if cattle are experiencing sub clinical effects of the disease without testing.
"Sub clinical milk fever is highly prevalent and the only way to know if it's occurring is to blood sample fresh calved cows. If blood calcium levels are below 2 mmol/litre in the first 24 hours after calving then subclinical milk fever is occurring. Usually at 1 mmol/litre, clinical milk fever will occur" he says.
Blood testing strategy will vary from farm to farm, but subsequent results should be used to discuss appropriate management changes with a vet and nutritionist.
Forages used in dry cow diets represent a significant contributory factor to subclinical milk fever. As a result, forages and the transition cow TMR should be tested regularly to assess macro-mineral levels. High levels of calcium and potassium in particular can predispose cows to milk fever.
James explains: "Potassium blocks magnesium absorption and affects important hormonal mechanisms, which effects how well a cow mobilises calcium after calving. As a result, feeding low potassium diets of under 1.4%DM of potassium is crucial to prevent milk fever, unless using a calcium binder. However our farm trial showed half of dry cow rations had higher than recommended levels of potassium and a third of TMR samples had dietary calcium of over 0.9%."
To address this, farmers could consider producing a low potassium haylage on ground that has little or no slurry applied or incorporating wholecrop into the diet.
If you would like to discuss milk fever prevention on your farm, contact James on 07977 027 855.
Find out how EBVC client, Robert Mallett has benefitted from regularly testing the ration to help control milk fever.