Feeding a free choice energetic mineral-vitaminsupplement to dry and transition cows:effects on health and early lactation performance

摘要

Diets or total mixed rations (TMRs) formulated for specific groups of animals are not always able to satisfy the nutrient requirements of individuals cows and this limit can became critical in key phases of the productive-reproductive cycle such as the dry and the transition periods, whose proper management is recognized to affect the entire subsequent lactation. Various nutritional strategy have been tested for the conduction of these critical phases and different tools have been developed to help farmers in preventing the metabolic and reproductive diseases typical of the fresh cow. Aim - The aims of the present work were to evaluate the use of a free choice energetic mineral-vitamin supplement as a tool for the nutritional management of dry and transition cows and to study its effect on cattle health and early lactation performances. Materials and methods - A randomized complete block design was performed on 20 Italian Holstein cows divided into two balanced groups: Control, fed hay and total mixed ration (TMR) and Treated, offered the same diet and the supplemental product as ad libitum licking feed. Group feed intake and individual dry matter digestibility, health, metabolic parameters, and productive and reproductive performances were monitored from the drying off to 100 days in milk (DIM). Results and discussion - The TMR was a fibrous mix with high level of NDF, low level of NFC and an average level of starch, while hay was a mixed hay characterised by a prevalence of grasses. The Treatedgroup consumed from 0.34±0.12 to 0.74±0.50 kg/d of supplement and in comparison with the Control group showed an higher hay intake during the colostral phase (5.98±0.44 vs 4.39±0.57 kg, P = 0.004) and an higher TMR intake during the post-partum period (16.16±1.43 vs 14.49±1.35 kg, P = 0.001). No differences were observed in dry matter digestibility at the intervals considered. Because of the higher quantity of energy and nutrient availability, treated animals showed a trend for a lower incidenceof ovarian cysts in the fresh period, produced a significantly higher quantity of colostrum (15.4±2.1 vs 5.8±2.8 kg; P = 0.010) and showed a tendentially higher immunoglobulin output (1403±222 vs 706±190 g; P = 0.069) such as tendentially higher cumulative milk production at 20 DIM (6321104 vs 517±134 kg, P = 0.058). Calving to first cycle interval was significantly reduced by treatment (19.8±2.0 vs41.7±5.2 days; P = 0.001).Conclusions - The use of free choice energetic mineral-vitamin supplements administered as ad libitum dietary component during dry and transition periods seems to be a viable tool for the nutritional management of the dry and transition cows. Under sub optimal nutritional field conditions, this practice appeared to positively affect dry matter intake, colostral phase performance and early lactation health status but also reproductive function resumption and milk production.