The influence of dry period feeding on liver fat and postpartum performance of dairy cows

Animal performances were monitored in 30 Friesean dry cows (18 multiparous, MP-cows and 12 primiparous, PP-cows) starting six weeks before calving to eight weeks after calving. The cows were kept indoors and fed individually with a prepartum diet containing either low, moderate or high energy (0.75, 1.00 or 1.25 of the calculated ME requirement) and supplemented with low ( 0.3 kg day(-1)) or high (1.5 kg day(-1)) rapeseed meal (RSM). The diets wer e consisted of 1.5 kg hay, 20-25 kg wilted grass silage and grain (barley a nd oat, 1 : 1 DM basis) with RSM. The average ME intake during six weeks of prepartum was 75, 97 and 123 MJ day(-1) on three different energy levels. After calving the cows were fed grass silage ad lib, 6.5 kg (primiparous) o r 8.5 kg (multiparous) grain and 1.5 kg RSM, Liver biopsy and blood samples were taken to determine differences in metabolites due to diet and parity. Reduction of prepartum energy allowance to 0.75 of the moderate level did not affect the calf's birth weight and colostrum composition. Cows fed prep artum low energy-high rapeseed meal diet (LEHR) showed a faster increase in feed intake and milk production after parturition. Continuous low feed int ake and milk production were observed in cows fed a prepartum high energy-l ow rapeseed meal diet (HELR). Milk yield was constantly lower for cows fed prepartum high energy diet, the difference being significant (p<0.01 and p< 0.05) at six and seven weeks of lactation. Overall milk yield also showed a linear decrease with energy feeding level and an increase (p<0.10) with RS M feeding levels. Prepartum high energy feeding increased (p<0.01) milk pro tein content. Neither energy nor RSM feeding level affected the liver fat i nfiltration of the experimental cows. Cow parity however showed a significa nt influence on liver fat content, beta-hydroxybutyrate (BHBA) and plasma g lucose. A week before calving, the plasma concentration of essential amino acids (EAA) was lower for cows fed prepartum low energy diet. During the fi rst four weeks of lactation, the concentrations of plasma non-esterified fa tty acids (NEFA) and insulin were similar for all the treatment group. (C) 1999 Elsevier Science B.V.