Also called hypocalcaemia, milk fever is due to low blood calcium. Calcium is important for many bodily processes including heart and muscle function and the animal’s body works very hard to maintain blood levels in the normal range. Late in pregnancy when the foetus is growing rapidly and early in lactation, the cow’s or ewe’s calcium requirement increases significantly and she needs to maintain blood levels by mobilising calcium from bone. Milk fever occurs if this mobilisation process is too slow to keep up with need. Older and/or more productive animals are more prone and stress, sudden changes to grazing, lush, low roughage feed or plants high in oxalates (chemicals which bind calcium to form insoluble salts) can all predispose to milk fever.
Affected animals can show signs such as a stiff or staggery gait, muscle tremors, weakness, tendency to lie down on their chest or their side, difficulty in getting up, depression, bloating and ultimately, death.
Preventing Milk Fever
Late in pregnancy, cows and ewes should be kept on low calcium feed to encourage their own ability to mobilise their bone stores more efficiently. At this time avoidance of any form of stress is important. Good quality hay and/ or grain should be supplied. After calving or lambing calcium intake should be increased and supplements such as loose licks can be provided and grazing of pastures higher in calcium (e.g. clover) is recommended. Vitamin D encourages absorption of calcium and mobilisation from bone and can also be given to cows before calving.
Treating Milk Fever
Treatment needs to be given as soon as possible but happily response is often very quick and complete. The treatment is calcium borogluconate solution (Flopak 4 in 1) by subcutaneous injection over a number of spots on the animal and is readily absorbed into the bloodstream. It can also be given intravenously under veterinary supervision if deemed necessary. As stated, affected animals will improve quickly although several treatments may be required. General nursing is also important such as keeping the animals in a warm, dry place, close to supervision and preventing them from lying flat on their side to avoid bloat. Access to clean water and good feed and calcium supplements all help.
- Calcium 27.5g/L (equivalent to 330gL calcium borogluconate)
- Magnesium 4.7g/L
- Phosphorus 12.2g/L
- Glucose 182g/L
By subcutaneous injection (or by intravenous injection by or under veterinary supervision).
- small cows: 500mL,
- Heavier cows: 500-1,000mL