Prevalence of subclinical diabetes in a commercial flock of dairy goats in India and its interaction with milk quality

Abstract

Blood plasma concentrations of random glucose, fasting glucose, intravenous glucose tolerance test (IVGTT) glycated haemoglobin, fructosamine, cholesterol, triglycerides and insulin were measured 5 times in 379 goats in 5 different days in order to evaluate the prevalence of subclinical diabetes in the commercial flock of dairy goats. Milk composition and milk antioxidant capacity was also evaluated after screening. Of the 379 goats that were screened for diabetic biomarkers, 45 animals had abnormal levels of the above mentioned indices. 16 animals out of the 45 had normal values on subsequent tests and in 5 animals out of the 45, only one or two diabetic biomarkers slightly elevated at a particular measurement; hence these goats were considered as normal. 24 animals (6.3%) were diagnosed a subclinical diabetic, based on the clinicopathological findings and subsequent monitoring: these goats had significantly higher levels of random glucose, fasting glucose, IVGTT, glycated haemoglobin, fructosamine and lower levels of insulin in all measurements. Milk of the subclinical diabetic goats had higher milk fat and lactose concentrations in comparison to non-diabetic goats (P<0.05). No significant difference between subclinical diabetic goats and non-diabetic goats (P≥0.05) in solid not fat, protein, total solids and ash contents were found. A positive and significant correlation (P<0.05) was found between fat content in milk and plasma concentrations of fructosamine (r=0.794) and triglycerides (r=0.715), and between milk lactose and plasma triglycerides (r=0.669). The antioxidant capacity of milk was lower in subclinical diabetic goats than in non-diabetic goats and the content of lipid peroxides was higher in subclinical diabetic goats than in non-diabetic goats (P<0.05). Our study revealed the prevalence of subclinical diabetes in commercial flock of dairy goats and showed that it is associated with impairment of milk quality, which was most likely associated with oxidative stress.