Feeding behaviour and metabolic condition of dairy cows during early lactation.

In dairy cow the transition period often results in enormous stress and may negatively impac��t Dry Matter Intake (DMI), milk production and herd health. The aim of this research was to study the feeding behaviour of dairy cows in early lactation and the relationship with the metabolic and health conditions. The trial was carried out on 14 multiparous Italian Friesian cows raised in an experimental free-stall barn. Animals were fed Total Mixed Ratio (TMR) once daily (at 07:30 a.m.) and raised, from 7 to 60 d after calving, in a pen equipped with 24 electronic feeding stations connected to a central computer (Bio Control A/S, Rakkestad, Norway) capable to record individual data on feeding behaviour. The data on feeding behaviour (number of meals, eating time per meal, feed intake per meal and rate of intake) were expressed per day and per day-time (from 07:00 a.m. to 07:00 p.m.) and nighttime (from 07:00 p.m. to 07:00 a.m.) period. Cows were bled, before TMR distribution, at -14, -7, 1, 3, 7, 14, and 30 d from calving and samples analyzed for the parameter of the Piacenza Metabolic Profile together to NEFA, BHBA, and creatinine. The BCS was evaluated at -7, 0, 30 and 60 d from calving, while milk yield and body weight were daily recorded. The animals were subdivided in two groups (G and L) according to the Liver Functionality Index (LFI), based on the behaviour of plasma albumin, total cholesterol and bilirubin in early lactation. The results were subjected to ANOVA (Mixed procedure of SAS), including LFI, DIM, period of the day, their interactions, and cow as random effect. During early lactation the behaviour of DMI was mainly related to the eating time per meal and the feed intake per meal; on the contrary, the number of meals per day changed only slightly. The DMI during the day-time period was on average 66% of daily DMI, this proportion did not change significantly during lactation. The animals with lower (worse) LFI (L) compared to the animals with higher (better) LFI (G) have shown: a) lower milk yield (P<0.01); b) lower DMI, mainly as consequence of a lower eating time per meal (25.0 vs. 32.7 min in L and G, respectively; P<0.05) and of a lower feed intake per meal (2.89 vs. 3.82kg DM in L and G, respectively; P<0.10), despite a greater number of meals per day (6.3 vs. 5.6 meals in L and G respectively; n.s.); c) lower values of plasma albumin and cholesterol, and greater of bilirubin, as consequence of LFI classification, together to greater values of the positive acute phase proteins (AAP+: haptoglobin and ceruloplasmin) before (n.s.) and after calving; d) greater values of plasma NEFA before calving and of NEFA and BHBA after calving; e) some health troubles after calving (mastitis and lameness). In conclusion our data show that feeding behaviour and daily DMI in early lactation was mainly related to the eating time and DMI per meal. An increase of plasma APP+/APP- ratio around calving was associated with a lower DMI in early lactation, together to a reduction of milk yield and a worsening of health condition.