Effect of energy sources (starch or fat) on high energy diet and chromium supplementation on serum concentrations of glucose, insulin, and non-esterified fatty acids on lactating dairy cows

• Grant number: 16/18991-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2016
• End date: October 31, 2017
• Field of knowledge: Agronomical Sciences - Veterinary Medicine
• Principal Investigator: José Luiz Moraes Vasconcelos
• Grantee: Ana Beatriz Montevecchio Bernardino
• 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 is to evaluate the influence of the energy source of the diet and chromium supplementation on serum concentrations of glucose, insulin, and non-esterified fatty acids (NEFA) on lactating cows. Cows 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. Serum concentrations of glucose, insulin, and non-esterified fatty acids (NEFA) will be evaluated before feeding. All variables will be analyzed using the MIXED procedure of SAS. Serum concentrations of glucose, insulin, and non-esterified fatty acids will be analyzed as repeated measures. (AU)