Use of metabolic profiles in dairy cattle in tropical and subtropical countries on smallholder dairy farms

Metabolic profile testing has generally been used as part of a multi-disciplinary approach for dairy herds in temperate climates. Our goal was to evaluate the effectiveness of the technique for identifying constraints on productivity in small herds in environments less favourable for milk production. Metabolites tested were chosen for stability in the sample after collection of blood, ease of analysis and practical knowledge of the meaning of the results. Blood levels of five different metabolites in low producing dairy cows belonging to smallholders in tropical and subtropical environments were measured. The study involved 13 projects with 80 cows in each, carried out in six Latin American, six Asian and one southern European country. Data was also collected on feeding, body condition (BCS) and weight change, parasitism and reproduction. In Chile, Mexico, Paraguay, Philippines, Uruguay and Venezuela globulin levels were high in more than 17% of cows sampled on each occasion. Globulin levels were also high in Turkey and Viet Nam on one or more occasions. In Paraguay 49% of cows had high globulin levels at 2-3 months after calving. These results suggest that inflammatory disease was present to a potentially important degree, although this was not always investigated and not always taken into account. In all countries except Mexico and Venezuela high β-hydroxybutyrate (BHB) levels before calving in many cows highlighted the presence of condition loss in late pregnancy, an important potential constraint on productivity and fertility. Fewer cows showed high BHB levels in lactation where change in BCS and weight was more sensitive for measuring negative energy balance. Urea concentrations were only found to be low in small numbers of cows suggesting that dietary protein shortages were not common. Albumin values were low mainly in cows where globulin values were high and so did not generally provide additional information. The exception was in China where pregnant yaks over Winter had high BHB and low albumin values suggesting that they were seriously underfed. This observation stimulated a successful nutritional intervention in the following winter. Inorganic phosphate values were within the reference range in most countries most of the time suggesting, contrary to expectation, that this mineral was not commonly a constraint. The use of metabolic profile testing proved valuable in drawing attention to important potential constraints on productivity in dairy cows in tropical and subtropical environments and in confirming those which were not. (author)