Impact of negative energy balance on production and fertility in Slovenian brown-breed dairy cows

Abstract

The aim of this study was to investigate the production and reproduction ability of Slovenian brown-breed dairy cows according to their exposure to negative energy balance (NEB). Body condition score (BCS), concentrations of metabolites such as non esterified fatty acids (NEFA), beta hydroxy butyrate (BHB), cholesterol and urea were measured on day 14 postpartum and progesterone profile was determined for each animal. The postpartum period was closely monitored from day 14 to conception by ultrasound examination in 10 day intervals. Reproductive parameters were followed up, also. Cows were divided in two groups according to NEFA and BHB concentrations with a threshold of 0.5 and 1.4 mmol/L, respectively. Cows with elevated NEFA and BHB levels (Group 2) in comparison to Group 1 expressed a higher decrease in BCS 30 days postpartum (0.64 vs 0.33 point; P<0.01), more abnormal progesteron patterns (P<0.001) and had a significantly longer interval to first progesteron rise (49.54 vs 33.82 days; P<0.05). Milk protein concentrations 30 days postpartum were significantly lower in Group 2 comparing to Group 1 (3.08 % vs 3.36 %, P<0.001) and protein ratio (FPR) 30 days postpartum was significantly higher in Group 2 (1.37 vs 1.21; P<0.05) comparing to Group 1. Measurement of NEFA and BHB concentrations, body condition scoring and milk data recording are found to be good criteria for the recognition of NEB in dairy cows in the early postpartum period. .