Prevention of Milk Fever: A Herd Health Approach to Dairy Cow Nutrition

The large increase in milk yield and the structural changes in the dairy industry of the world have caused major changes in the management and feeding of dairy cow. This increase has led to the development of a sustainable herd of health consciousness. Veterinarians working in such cattle farms have begun to realize the importance of preventive medicine services in terms of effective herd health management in order not to consider themselves as a physician dealing with treatment alone. Herd health and production management program represent the first level to optimize dairy farm performance. One of the most important keys to optimize performance is nutrition. There are a few diseases in dairy cattle which occur due to improper feeding or nutritional management. Milk fever is one of such disorders which occurs due to faulty feeding practices during the pregnancy and/or immediately after calving of dairy cattle [1-3]. Milk fever can also be called the “gateway disease” as it increases the risk of other diseases such as acidosis, ketosis, mastitis, retained placenta, displaced abomasum and metritis [4]. De Garis & Lean [5] have reported that the incidence of hypocalcemia in dairy cows is 3.45% in North America, 6.17% in Europe, and 3.5% in Australia [5]. The economic losses caused by milk fever have been reported as 334 USD for each case including the estimated production losses and treatment costs [6]. However, losses from subclinical hypocalcaemia are estimated to be several times more than clinical cases in a herd [7]. Therefore, prevention of milk fever or subclinical hypocalcaemia in periparturient animals has significant importance in finance and welfare.

Milk fever (hypocalcaemia) is caused by the disturbance in “Ca homeostasis”. Mainly three factors influence calcium homeostatic mechanism:

a. Excessive loss of Ca++ in the colostrum beyond the capacity of absorption from intestine,

b. Impairment of absorption of Ca++ from intestine at parturition, and

c. The slowness of the mobilization of Ca++ from storage in skeleton that leads to problems in maintaining normal serum levels [8].

The key to prevention of milk fever is management of a closeup dry cow or management during late pregnancy. The traditional way of preventing milk fever is to limit Ca intake during the dry period. Several methods have been proposed to prevent milk fever. These include: regulation of the ratio of rations Ca and phosphorus (P), feeding the animals with different mineral salts, vitamin D, metabolites or synthetic analogues, intramuscular and intravenous parathyroid hormone (PTH)applications and increasing the rate of ration acidity [9] (Table 1).

Table 1: Nutritional factors responsible for milk fever [16].

There are different control methods to prevent milk fever related to herd management practices such as [10]:

a. Dietary magnesium level control peripartum.

b. Body condition control.

c. Controlling dietary carbohydrate intake peripartum.

d. Shortening of the dry period

e. Prepartum milking.

f. Reduced milking in early lactation.

In this review, nutritional approach for the prevention of milk fever will be explained briefly in terms of the most commonly used.

Dietary calcium restriction in the close-up dry period

This has been the traditional approach and the principle is based on the theory of preventing the calcium homeostatic mechanisms from becoming quiescent during the dry period. According to the National Research Council [14], the recommended Ca and P ratios for a mature cow during the dry period should be 0.39% (33-43g) and 0.24% (20-26g) in the dry matter. However, for this method to be successful, prenatal Ca consumption should not exceed 10-30g per day [11]. It is difficult to formulate such low calcium diets unless whole crop or corn silage is being fed and the animal still requires a certain level of dietary calcium to maintain bone integrity. In such a situation supplementation of zeolite and vegetable oils can be done as both are known to reduce the absorption of calcium sufficiently.

Dietary Cation-Anion Difference (DCAD)

Dietary cation-anion difference [DCAD = (Na + K) – (Cl + S)] of ration is directly related to milk fever. The DCAD of ration can easily be calculated if percentages of concentrations of sodium (Na), potassium (K), chlorine (Cl) and sulphur (S) ions of the ration are known [12,13]. This strategy was developed in order to combat the high potassium in their forages, which makes the low calcium strategy ineffective. This can be very effective, but it is more difficult to undertake than the low calcium strategy. Potential problems include low palatability of some anionic salts and the requirement for regular urine pH testing.

A negative DCAD (-50 -100mEq/kg DM) has been shown to have an effect on calcium metabolism [11,14]. It can induce a more acidic intestinal pH for calcium absorption and facilitate recruitment of bone reserves, increase the excretion of calcium in urine and consequently activate calcium reabsorption and recruitment processes [11, 15]. In a recent study, Bani Hassan et al. [1] reported that adjusting DCAD at neutral values (0, -30mEq/ kg range) may both lower the milk fever prevalence and increase ration palatability by lowering acidogenic salts in the ration. A useful method for determining whether an animal is responding to added dietary anions is to monitor urinary pH. Urinary pH between 5.5 and 6.2 is associated with effective administration of anions [16-18]. If urinary pH is <5.5 dietary anions should be reduced to avoid severe metabolic acidosis [11].Additional oral calcium supplementation

It is not advisable to use this method as a first line of milk fever prevention. Supplementation should be done depending on the quality of ration provided and the level of calcium in it, as there are chances of negative effects for breaking of calcium homeostatic pathways in the body of animal. The commercially available forms of calcium chloride decrease the incidence of milk fever and abomasum displacement when given within 12-24 hours following delivery [19]. However, it should be kept in mind that preparations containing calcium chloride may cause ulcers in the mucous membranes of the mouth and digestive tracts.

In the prevention of milk fever in high-milk cows, the following measures can be taken with regards to nutrition in view of the above information:

1. During the dry period, for example, a cow weighing 600 kg should consume 30-40 g Ca / day, 20-25 g P/ day, with Vitamin A, Mg, K, Se (maximum 50.000 IU), vitamin D (15.000-25.000 IU). and vitamin E requirements must be met [14].

2. If milk fever is a problem of the herd, daily Ca consumption in the last weeks of the dry period should be limited to 20-25 g per animal. In this way, high P and low Ca intake activates the parathyroid gland, contributing to Ca mobilization faster than the postnatal bones of the animal and reduces the risk of milk fever.

3. The most important cause of milk fever is the high Ca and K in the dry period due to the use of high amounts of leguminous roughages or unsuitable mineral additives. Foods rich in calcium should not be fed before calving particularly during the last trimester of pregnancy period. In order to prevent milk fever, keeping the ration K level below 1.8% is extremely important [17].

4. Magnesium also plays an important role in maintaining calcium homeostasis around calving. Total intakes of about 40 to 50 grams of dietary Mg (about 0.30 to 0.45% of diet dry matter) have been suggested [5].

5. In cases where high rumen pH is suspected, 100g/day ammonium chloride (or ammonium sulfate) may be given by mixing the concentrate before the first two days before and after the delivery.

6. If milk fever is common in the herd, feeding with a ration of DCAD= -150, -200mEq/kg DM with anionic salt additive in the last 3-4 weeks of the dry period contributes to the control or prevention of milk fever.

7. The most important finding that can show the adequacy of nutrition-related measures is the urinary pH to be taken 1-2 weeks before delivery. If the urine pH is greater than 8, the possibility of milk fever is high. The optimum urinary pH with low probability of milk fever has been reported to be 6.0-6.5 for Holstein cows and 5.5-6.0 for Jersey cows [18].

8. The blood Ca level within 24 hours before delivery is above 8 mg/ 100 ml, indicating that there is no problem with milk fever.9. The administration of 75g of CaCO₃ after delivery may also reduce the risk of milk fever.

There are different control methods to prevent milk fever related to nutrition. However, there is only limited information about how the different methods are most efficiently implemented as detailed strategies. Hopefully, the future will bring more detailed information on the optimal use of control methods under different management conditions.

1. Goff JP, Horst RL (1997) Effect of dietary potassium and sodium, but not calcium, on the incidence of milk fever in dairy cows. J Dairy Sci 80(1): 176-186.
2. Kocabagli N (2012) Nutritional Approach for Prevention of Parturient Paresis in High Producing Dairy Cows. Turkiye Klinikleri J Vet Sci 3(1): 26-31.
3. Mulligan FJ, O Grady L, Rice DA, Doherty ML (2006) A herd health approach to dairy cow nutrition and production diseases of the transition cow. Animal Reproduction Science 96(3-4): 331-353.
4. Ryan EG, O’Grady L (2004) The economics of infectious and production diseases in dairy herds. In: Herd Health Planning. Veterinary Ireland Publishers PP (3-50).
5. De Garis PJ, Lean IJ (2008) Milk fever in dairy cows: A review of pathophysiology and control principles. Vet J 176(1): 58-69.
6. Guard C (1996) Fresh cow problems are costly: Culling hurts the most. Page 100 in Proc. 1994 Annu. Conf. Vet., Cornell Univ., Ithaca, NY.
7. Houe H, Ostergaard S, Thilsing-Hansen T, Jørgensen RJ, Larsen T, et al. (2001) Milk fever and subclinical hypocalcaemia: an evaluation of parameters on incidence risk, diagnosis, risk factors and biological effects as input for a decision support system for disease control. Acta Vet Scand 42(1): 1–29.
8. Sharma N, Gupta SK, Soodan JS, Singh R (2006) Important production diseases of dairy animals-A review. Dairy Planner 2(11): 6-8.
9. Patel VR, Kansara JD, Patel BB, Patel PB, Patel SB (2011) Prevention of milk fever: nutritional approach. Veterinary World 4(6): 278-80.
10. Thilsing-Hansen T, Jørgensen RJ, Østergaard S (2002) Milk fever control principles: a review. Acta Vet Scand 43(1): 1-19.
11. Horst RL, Goff JP, Reinhardt TA, Buxton TR (1997) Strategies for preventing milk fever in dairy cattle. J Dairy Sci 80(7):1269-1280.
12. Goff JP (2008) The monitoring, prevention and treatment of milk fever and subclinical hypocalcaemia in dairy cows. Vet J 176(1): 50–57.
13. Overton TR, Waldron MR (2004) Nutritional Management of Transition Dairy Cows: Strategies to Optimize Metabolic Health. J Dairy Sci 87: E105–E119.
14. Kocabağlı N, Kahraman R, Abaş İ, Eseceli H, Alp M (2001) The effects of anionic salts and probiotic in prepartum diets on milk production and quality and incidence of milk fever in dairy cows. Tr J Vet Anim Sci 25(5): 743-51.
15. Leno BM, Ryan CM, Stokol T, Kirk D, Zanzalari KP, et al. (2017) Effects of prepartum dietary cation-anion difference on aspects of peripartum mineral and energy metabolism and performance of multiparous Holstein cows. J Dairy Sci 100(6): 4604-4622.
16. Kocabağlı N, Kahraman R, Abaş İ, Eseceli H, Alp M (2001) The effects of anionic salts and probiotic in prepartum diets on milk production and quality and incidence of milk fever in dairy cows. Tr J Vet Anim Sci 25(5): 743-51.
17. (1989) National Research Council. Nutrient Requirements of Dairy Cattle. 6th Rev Upd ed. Washington, DC: National Academy Press P 168.
18. Gaynor PJ, Mueller FJ, Miller JK, Ramsey N, Goff JP, et al. (1989) Parturient hypocalcemia in Jersey cows fed alfalfa haylage-based diets with different cation to anion ratios. J Dairy Sci 72(10): 2525-2531.
19. Jardon PW (1995) Using urine pH to monitor anionic salt programs. Compend Contin Educ Pract Vet 17: 860.