Silagem de raiz da mandioca no suplemento para vacas leiteiras mantidas a pasto: efeitos sobre a produção, aspectos do queijo, custo e comportamento animal.

Abstract

The objective was to evaluate the production yield, physical-chemical and sensory characteristics, and determine the economic cost of producing fresh Minas cheese, along with assessing ingestive behavior with the inclusion of cassava root silage replacing corn in the dietary supplement for dairy cows. Ten Girolando cows with an average weight of 373.45 ± 63.55 kg and an initial average of 76 days of lactation were used, distributed in two simultaneous 5 × 5 Latin squares. Five treatments were evaluated: I – cows in pasture without technical supplementation (SSC); II - grazing cows receiving 5 kg of concentrated supplement with 0% SRM; III - grazing cows receiving 5 kg of concentrated supplement with 26% SRM; IV - grazing cows receiving 5 kg of concentrated supplement with 52% SRM; and V - grazing cows receiving 5 kg of concentrated supplement with 78% SRM. The composition and characteristics of the cheeses were analyzed, as well as production costs. Vacation behavior was observed, including activities, feeding efficiency, and physiological parameters. Behavior observation occurred on the 10th day of each experimental period for 24 consecutive hours, evaluating activities (grazing, ruminating, idleness, other activities), chewing, feeding efficiency, rumination efficiency, and physiological functionalities. Supplementation improved cheese production and protein content (P<0.05), while the inclusion of cassava root silage (SRM) did not affect cheese quality (P>0.05). However, the higher level of cassava root silage increased the cost of the supplement by 48.91%. Daily supplement expenditure per cow increased by 42.80% with the highest cassava root silage level and reduced profits per kilogram of cheese compared to the non-SRM treatment. SSC animals spent less time idle (P<0.004) and more time grazing (P<0.009). They also had greater NDF feeding efficiency, greater NDF rumination efficiency, greater NDF consumption (P<0.001) and had lower heart rate (P<0.014), RR (P<0.001) and TR (P<0.022) and lower surface temperature of the right side (P<0.003) and side of the udder (P<0.047). The inclusion of cassava root silage (SRM) in the concentrate did not affect the behavior (P>0.284) or feed efficiency of cows (P>0.170), but reduced fiber intake (P<0.009) and had a quadratic effect on rectal temperature (P<0.053). The inclusion of up to 78% of cassava root silage in replacement of corn in the supplement does not harm the production, composition, and quality of Minas frescal cheese, but it increases the cost of the supplement, thereby reducing profitability. Conversely, technical supplementation, although reducing the feeding and rumination efficiency of neutral detergent fiber (NDF), increased the feeding efficiency of dry matter (DM) and vacation rest time, consequently reducing grazing time.