Effect of energy sources (starch or fat) and chromium supplementation, on high energy diet, on insulin resistance parameters on lactating dairy cows

• Grant number: 16/18287-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2016
• End date: October 31, 2017
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: José Luiz Moraes Vasconcelos
• Grantee: Leticia Aparecida Casarin Lourenço
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

The objective of this study was to evaluate the influence of the energy source of the diet and chromium propionate supplementation on insulin resistance parameters using glucose tolerance test on lactating dairy cows and receiving in a 2 × 2 factorial arrangement design: : 1) concentrate based on ground corn (CRN; n = 20) or fat (GP; n = 20), and 2) supplemented (n = 20) or not (n = 20) with 2.5 g/day of Cr-propionate. During the experiment (day 0 to 200), 40 multiparous, non-pregnant, lactating Gir × Holstein cows (initial days in milk = 80 ± 7) will be offered corn silage for ad libitum consumption, and individually received concentrate formulated to allow diets to provide 160% of their daily requirements of net energy for lactation. Cow BW will be recorded weekly and body condition score (BCS) will be recorded each 15 days. Milk production will be recorded daily and milk samples will be collected weekly. Glucose tolerance tests (GTT; 0.5 g of glucose/kg of BW) will be performed on days -3, 100, and 200, blood samples will be collected -15, 0 (prior of glucose infusion), 10, 20, 30, 45, 60, 90 and 120 minutes after beginning of glucose infusion. All data will be analyzed using the SAS procedures.