Tamil Nadu contributes more than 5 % of total milk production in the country and ranked 10th among high milk producing states in India (Policy note 2022). Healthy cows are highly essential to augment milk yield. High yielding cows are prone for metabolic disorders in the transition period. The time period from 3 weeks before calving to 3 weeks after calving is defined as the transition period. During transition period, managing right nutrition improves milk production and reproductive performance. Milk fever is the one of transition period diseases which is most common in mature dairy cows around 5 - 10 years of age (Suttle 2010). Older animals are more susceptible and the incidence of milk fever increases to above 10% from 3rd to 7th calving (Radostits et al. 2000). The economic importance of milk fever is reduction in quantity of milk yield which is around 142 kg per lactation (Bar et al 2005). Prevalence of milk fever in cattle is 13.67% and for buffalo it is 11.99%. Death arises in dairy cows if not treated in time. The treatment is expensive for recovery of animals. Total economic losses of the farmer due to milk fever is Rs. 1068 /- per affected animal (Thirunavukkarasu et al 2010).
To overcome this problem, an innovative low cost approach in transition cows to reduce the incidence of milk fever through feeding anionic salts was carried out at the Institute of Animal Nutrition, Kattupakkam, Chengalpattu district, Tamil Nadu, India which is located 83.2 meters above mean sea level, at 12.98 °N Latitude and 79.71 °E Longitude and this region generally experiences hot and humid climatic conditions throughout the year.
The feeding practices adopted by the farmers for the animals affected by milk fever were documented in Kancheepuram district of Tamil Nadu. The raw feed ingredients and the fodders were analyzed for sodium, potassium, chloride and sulphur contents and the Dietary Cationic and Anionic Difference was calculated as per the formula: DCAD mEq/100g DM = (Na + K) – (Cl + S).
The common feeding regimen followed in the affected animals are paddy straw, bajra napier hybrid grass, cooked rice, groundnut oil cake, bengal gram chunnies, wheat bran, black gram apart from grazing in the community land. Based on the feeding practices of the affected animals, DCAD value was found to be positive (2035.64±144.58 mEq in Kg DM feed). This could be the reason for the animals to be affected by milk fever. For close up cows, DCAD value in feeds should be negative for higher serum calcium levels. For DCAD to have an effect on blood pH and hence milk fever, it must be at 0 mEq/100 g DM or below (Roche et al 2003). Anionic salts activates calcium metabolism through bone resorption and increased calcium absorption. Hence, supplementing anionic salts (calcium sulphide and magnesium chloride) in the existing feeding practices is imperative in improving serum calcium level of dairy cows in transition period. Data collected were analyzed using analysis of variance (ANOVA) using IBM SPSS statistics 20.
DCAD value of hydroponic fodder bajra was calculated with the above formula and was found to have negative value (-5.45 mEq/100g DM) whereas concentrate feed, paddy straw and cumbu napier hybrid grass analysed value is 2.97, 40.47 and 18.71 mEq/100g DM respectively. Thus the negative DCAD value of hydroponic fodder bajra can reduce the requirement of anionic salts in achieving the higher calcium status in dairy cows.
For conducting trial with anionic salts, seven pregnant cows in farm and nine pregnant cows in field conditions approximately three weeks before calving were selected. The selected cows were supplemented with anionic salts along with concentrate feed / bran and oil cakes during the last three weeks before parturition. DCAD value of the ration to be fed to experimental cows in transition period was adjusted to -15 to -10 mEq / 100 g dry matter by feeding anionic salts viz., calcium sulphide and magnesium chloride along with hydroponic fodder bajra to achieve the urine pH around 6.0 - 6.5.
Anionic salts supplementation for three weeks prior to calving resulted in significant (P<0.05) increase in the serum calcium level. In post supplementation, average increase in the serum calcium level is 0.93 mg/dl presented in table 1. Anionic salt supplementation resulted in increased serum calcium level by 10.80 per cent. The negative DCAD value contributed by feeding hydroponic fodder bajra (9 Kg / animal /day) to transition cowsis -6.13 mEq/100g DM, which level could also be obtained by feeding 0.26 grams of calcium sulphide at the cost of Rs.0.49 paise only.
Table 1
Effect of anionic salts on serum calcium level (mg/dl) in transition cows
Animal from
|
Pre supplementation calcium level (mg/dl)
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Post supplementation calcium level (mg/dl)
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Institutional farms*
|
9.17a±0.39
|
9.94b±0.42
|
Farmers field**
|
8.80a±0.58
|
9.85b±0.61
|
Overall mean
|
8.96a±0.36
|
9.90b±0.38
|
*Mean of 7 samples, **Mean of 9 samples
a,b Means bearing different superscripts within row differ significantly (P<0.05)
Hence, anionic salts supplementation helps in increasing the serum calcium levels and reduces the incidence of milk fever in transition cows. Further, the feeding cost of anionic salts (Calcium sulphide and magnesium chloride) for three weeks (21 days) is Rs.55.65/. The low cost approach has to be validated in more number of animals so that the technology developed can be further propagated on a large scale basis to reduce the occurrence of milk fever in dairy animals and thus increasing milk production.