Effect of dietary supplementation of organic chromium in lactating cows

Abstract

A study was conducted to assess the effect of dietary supplementation of organic chromium on the milk production and metabolic profile of the crossbred cows in early lactation. Twelve healthy crossbred cows having a peak yield of minimum eight litres in their previous lactation were divided into two groups of six each, as uniformly as possible with regard to age, milk yield and parity and were randomly allotted to two dietary treatments, T1 consisting of basal concentrate mixture and paddy straw/ grass as roughage and T2 consisting of basal concentrate mixture supplemented with organic chromium at 2 ppm level as chromium propionate and paddy straw / grass as roughage. All the experimental animals were fed as per ICAR standards (1985) and maintained on their respective feeding regime from the day of calving to 100 days of lactation. Average dry matter intake, body weight, milk yield, milk fat percentage, total solids, solids not fat, haematological parameters viz. haemoglobin, plasma urea nitrogen, serum cholesterol, glucose, triglycerides, serum minerals, incidence of metabolic disorders and reproductive performance were the criteria employed for evaluation. Average body weight of animals revealed no significant difference for the both groups during all the fortnight studied. The average daily dry matter intake linearly increased as the lactation progressed in both the groups. Dry matter intake by the animals of T2 was comparatively better than the animals of T1 with a significant increase (P<0.05) during the sixth fortnight. Average daily milk yield increased significantly during the seventh fortnight and for 100 days of lactation in T2 (P<0.05). The animals in T2 maintained the peak yield for a longer duration compared to the T1. There was no significant difference in any of the milk composition parameters between the treatments. The haematological parameters such as haemoglobin, plasma urea nitrogen, serum glucose, cholesterol, and triglycerides estimated at the first, seventh and fourteenth week of lactation were not significantly affected by the two dietary treatments. The serum mineral concentrations of calcium, magnesium and phosphorus showed no significant difference while serum chromium levels showed a significant increase (P<0.05) between the two groups in the fourteenth week. The digestibility coefficients of the nutrients viz. dry matter, crude protein, crude fibre, ether extract, nitrogen free extract, acid detergent fibre and neutral detergent fibre were not found to be influenced by the organic chromium supplementation. There was no incidence of metabolic disorders such as hypocalcaemia, hypomagnesaemia and ketosis in both groups of animals. The cows supplemented with organic chromium (T2) showed earlier postpartum heat signs which indicated that the postpartum reproductive performance was influenced by the supplementation. It could be concluded from the results obtained in the present study, that organic chromium supplementation at 2 ppm in the concentrate mixture improved the dry matter intake, total milk production and helped to maintain the peak yield as well as persistency of milk production in early lactating crossbred cows. The study also revealed that the postpartum reproductive performance has also been influenced favourably by the supplementation of organic chromium in crossbred cows