Assessment of mineral status of cattle in Kerala

Abstract

To assess the present feeding conditions as well as the mineral status of cattle in Kerala, a survey work was conducted covering all the districts under the different agro-climatic regions in the state. From each district, 50 per cent of the taluks and from each taluk, two villages were selected for the survey work. From each village, nine samples of blood were collected from lactating cattle maintained by three categories of farmers (large, medium and marginal) based on socio-economic conditions. 'Samples of soil and feeds and fodders fed to cattle were also collected from different regions for the estimation of major as well as trace elements. Nutritional status of animals and incidence of nutritional deficiency conditions were assessed by using a proforma supplied to each farmer and also from the clinical cases recorded in various veterinary institutions in the concerned districts. Dietary intake of minerals by lactating cattle was calculated from the, information gathered during the survey work on the quantities of feeds and fodders fed and from the results on the mineral analysis of samples of feeds and fodders collected. The results on the nutritional survey indicated that majority of farmers maintained crossbred cows and a small proportion in all districts practised fodder cultivation for

feeding their animals. The animals in all districts received both straw and grass as roughage. As concentrate feeds, majority of farmers used a mixture of compounded feed and concentrate feed ingredients. Feeding of separate mineral mixture was practised in all the districts. From the results of analysis of soil, it was seen that while the level of iron in soil from all the districts was much higher and level of magnesium and zinc adequate, there was a general deficiency of copper and manganese. Phosphorus deficiency was noticed only in Kottayam district, but levels of calcium were low throughout the state except in Kasargod district. The results of analysis of concentrate mixtures revealed that the levels of iron in all the districts were much higher, phosphorus, magnesium and copper adequate, calcium adequate except in Idukki and Kasargod, zinc adequate except in Palakkad and manganese adequate except in Alleppey, Kozhikode and Kasargod. But the levels of sodium and potassium were found to be lower in all the districts. The mineral levels in the various concentrate feed ingredients collected from the different districts were found to be within the normal range. The mineral concentration in the different mineral mixtures collected during the present study revealed that none of the mineral mixtures analysed, was found to conform fully to the BIS Standard, the contents of most of the minerals

being either higher or lower, an observation which warrants strict regulations of quality control of all mineral mixtures marketed in the country. Analysis of local grasses collected during the survey work revealed that manganese levels were lower in all districts except Kottayam. Deficiency of phosphorus and copper were more wide spread, followed by calcium and deficiency of zinc, sodium and potassium scattered in nature, while the iron levels in all districts were much higher. Wide variations were observed in the mineral concentration of paddy straw collected from different districts, the variations being mainly attributable to the differences in the variety of straw fed to the animals. Analysis of blood serum collected from lactating cattle from different districts revealed a normal mineral status in regard to all the minerals except calcium for which slightly lower levels were observed in animals from Kottayam, Wyanad and Kasargod districts. More cases of reproductive disorders other than abortion and dystocia were recorded in the areas surveyed than either metabolic or nutritional deficiency. The dietary intake of minerals by lactating cattle in regard to all major and minor elements was not only satisfactory but was much higher in all districts except for

calcium, the intake of which was relatively inadequate in Pathanamthitta, Kottayam, Idukki, Malappuram, Kannur and Kasargod districts. From an overall evaluation of the results obtained in the present study, it can be inferred that the animals in all districts maintained a satisfactory mineral status for all minerals except for calcium, in spite of a generalised deficiency of copper and manganese and a scattered deficiency of calcium, phosphorus and magnesium in soils and local grasses. Slightly lower blood calcium values were recorded from Kottayam, Wyanad and Kasargod districts. The lower dietary intake of the element in these areas, probably is due to the differences in the type of feeds and quality of mineral mixture provided to them. However, marginal deficiencies of minerals which may go undetected, lower utilisation of minerals due to their interactions or imbalances or deficiencies of major nutrients particularly energy, might also be probable contributory factors for the higher incidence of reproductive disorders reported from veterinary institutions in the surveyed areas.