Milk fever in cows usually occurs within 72 hr of parturition.
The disease can contribute to dystocia, uterine prolapse, retained fetal membranes, metritis, abomasal displacement, and mastitis. Milk fever develops in roughly three stages so that it should be observed by any competent herdsperson. In the first two stages, recovery can be obtained. In the third stage, recovery is doubtful as there is little time to deal with it.
By stage 3, cows are in a state of considerable distress and lose consciousness progressively to the point of coma. They are unable to maintain sternal recumbency, have complete muscle flaccidity, are unresponsive to stimuli, and can suffer severe bloat. As cardiac output worsens, heart rate can approach 120 bpm, and peripheral pulses may be undetectable. If untreated, cows in stage 3 may survive only a few hours. The farmer has the problem of feeding the new-born calf.
The distress of calcium deficiency is a nutrient disease caused not only by inadequate nutrition but by insufficient nutrition and it is contrary to the first of the Five Freedoms: “Freedom from thirst, hunger and malnutrition- by ready access to fresh water and a diet to maintain full health and vigour.”
Magnesium deficiency (grass staggers or hypomagnesaemia) causes similar diseases and is primarily associated with low levels of magnesium (Mg) in spring pasture. This can be exacerbated by the application of artificial fertilizers that can reduce magnesium availability. Early clinical signs of acute magnesium deficiency include hyperexcitability and a 'staggering' gait. The condition can proceed to death within hours, so prevention is critical. Supplementing the diet or water with magnesium is typically used as a preventive for magnesium deficiencies in spring.
The risk of milk fever can be greatly reduced by attention to feeding practices during late pregnancy and transition from dry to lactating. Offering cows low levels of calcium and potassium during the late dry period enables cows to begin mobilizing body reserves of calcium from bone and thus prevent sudden plasma calcium deficiencies (hypocalcaemia) during early lactation. A more recent strategy for dry cows close to calving (3 to 4 weeks pre-partum) may involve manipulating the dietary cation:anion balance (DCAB) to induce a mild metabolic acidosis and thereby encourage calcium and phosphorus mobilization during late pregnancy.
Clinical milk fever is thought to affect between 4-9% of the UK’s dairy cows, while evidence suggests the subclinical form of hypocalcaemia, which causes significant production losses, can affect up to 39%. Intensive as well as extensive farming provide examples of milk fever and as the saying goes, the cow is often “milking off her own back” at the time of calving.
A recent study of the subject in the Veterinary Record describes Milk fever in cattle as “a serious health and welfare problem in dairy farming with considerable economic cost implications”. The disease involves the action of the parathyroid gland and can affect other species, such as sheep and goats.
At this time of year, cows are particularly troubled by nuisances such as flies and other insects, adding to their misery. The eye disease New Forest Eye (infectious keratoconjunctivitis) is transmitted by flies and is considered to be the most serious eye condition of cattle in the UK. Ear tags containing a fly deterrent have been used as a preventative measure. Other diseases of particular concern include Schmallenberg disease, blue tongue and lime disease, to name but a few.
To prevent disease or to revive animals requires various forms of vaccination or bolusses, usually provided by Big Pharma. For instance, Norbrook’s Calcitrace D3 bolus, which provides 48 hours of calcium release. The full page advert on the back of the Veterinary Record warns farmers that “it’s time to reduce the risk of milk fever”. Calcitrace contains calcium chloride, calcium sulphate, magnesium, phosphate and vitamin D3. The advert is illustrated by a picture of a cow and her newly delivered calf, with her grossly distended udder. The pictures don’t show the cow in her agony.
Cows are a subject of critical concern through their use as mere cogs in the machine of mechanised dairying. Supermarkets aren’t going to pay high prices for milk in bulk if they have to pay for such incompetence. So they are hoping that robotically milked cows will yield milk that can be tested for nutritional disturbances in the feed, saving herdspeople time. However, calcium deficiency is common in humans and is not fully understood in humans or animals, so there are likely to be serious accidents.
In any case, we want to get rid of the evils of the dairy industry. The Prime Minister has been commending British inventors. Why then does he let his Minister of Agriculture ignore the efforts going into investment in plant foods such as the Vegetarian Nutrition Research Centre (VNRC) which has provided exciting possibilities in alternatives to milk and related products and continues to do interesting work?
The Centre has revived research that was done after WW2 to widen agriculture to produce more variety in plant-derived eating rather than depending on methods that are clearly inadequate. Latterly ex-President Clinton has given a similar device to the American nation.
We also have some good news to celebrate: new non-dairy ice cream and chocolate, and now a product from Australia – yogurt made from coconut milk. So we think a more positive view can be taken in moderate amounts to meet the inefficiency and cruelty of dairy produce in an appropriate way.
 R. D. Murray et al (2008). Historical and current perspectives on the treatment, control and pathogenesis of milk fever in dairy cattle. Veterinary Record 163:561-565