Uso de ensilaje de grano húmedo y/o alimento concentrado en la suplementación de vacas mestizas en los Llanos Centrales venezolanos

Abstract

To evaluate the effect of type of supplement on milk production (MP), glucose (GLU), cholesterol (CHOL), urea nitrogen (UN) and body condition biometric index (BCBI) from 30 to 120 days postpartum dairy cattle were evaluated. Treatments were: a) EN: 2kg of moist grain silage (MGS; 18% crude protein) + Block mineral (BM) ad libitum (n=9); b) PRO: MGS 1kg + 2kg of concentrate (22.5% crude protein) + BM (n=9).The data were analyzed by ANOVA for repeated time measures, including the effect of treatment, day or weeks of assessment and their interaction. Additionally, Pearson correlation was performed for BCBI.

There was no effect of treatment (P>0.05) on MP (kg): 8.7 ± 2.6 (EN) y 9.9 ± 2.3 (PRO). Body weight (BW) and body mass index 1 and 2 (BMI1 and BMI2) improved with advancing lactation, with means: BW of 395.1 ± 55.1 and 418.5 ± 41.7 (P>0.05); BMI1 (kg/m2) of 227.0 ± 23.5 and 265.0 ± 69.9 (P>0.05); BMI2 (kg/m2) of 265.0 ± 69.9 and 207.5 ± 25.0 (P<0.05) for EN and PRO, respectively. Body condition (BC) postpartum was equal in both treatment (P>0.05). The correlations were BW-BC, 0.35 (P<0.01); BW- BMI1: 0.34 (P<0.01) and BW-BMI2: 0.58 (P<0.01). GLU (mg/dL) was within the range of this species: 60.5 ± 13.1 (EN) and 57.1 ± 11.5 (PRO) (P>0.05), with increases from 90 days postpartum. COL increased between 45 and 75 days and then decreased to 90 days postpartum (P<0.01) with means (mg/dL) of 141.4 ± 38.4 (EN) and 138.4 ± 34.6 (PRO) (P>0.05). The results demonstrate that the metabolism of these cows prioritized in energy protection mechanisms, because there was no evidence of improvements due to supplementation with additional protein.