In order to verify adequacy of diet fed to lactating cows is priority evaluating some productive and reproductive indexes of herd. Therefore, in certain conditions it can be useful to verify also the apparent digestibility of ration. For this purpose a digestion trial was carried out using two internal markers, AIA (acid insoluble ash) and lignin, to compare in vivo vs estimated values of OMD and ED. In the same time, the effect of parity on OM, GE, NDF and ADF digestibility was also evaluated. Height Italian Holstein cows, four primiparous (PR) vs four multiparous (ML), at the fourth lactating month, were fed 23.27 kg DM/die of the same TMR ensuring no orts. Corn silage, alfalfa hay-silage and natural meadow hay based TMR (CP: 16.38%, NDF: 34.49%, MFUnits (French Milk Feed Units)/kg: 0.97, AIA: 0.96%, lignin: 2.87% on DM basis, forage percentage 40,5% and feeding level >4.2) showed 75.68 and 74.01 % estimated OMD and ED respectively. In vivo digestibility values were lower than estimated and the coefficients obtained by AIA were unexpected and significantly (P<0,01) lower (OM: 56.25%, GE: 53.87%) than lignin (OM: 66.99%, GE: 65.19%). For this reason and because the recovery of AIA and lignin was 34.70 and 103.20 % respectively, the AIA coefficients were retained unreliable for purpose. According literature, comparison between estimated and in vivo digestibility lignin values showed a reduction of 2.7 points for point of feeding level over the maintenance, confirming the importance of discounts proposed by Van Soest for high producing dairy cows. No statistical interactions between marker and parity were observed. The parity didn’t showed to modify digestible pattern of diet.
|Autori:||LIPONI G; DE VINCENZI SERGIO; CESTOLA ELISA; GENTILE DANIELE; GATTA DOMENICO|
|Titolo:||Verifica della digeribilità della razione in bovine in lattazione|
|Anno del prodotto:||2007|
|Appare nelle tipologie:||1.1 Articolo in rivista|