Qualidade do queijo e leite de vacas recebendo dietas com substituição do concentrado convencional por farelo de glúten de milho

Abstract

The Northeastern dairy farming is characterized by the constant pursuit of technological improvements in order to optimize resources and achieve profitable results, especially when considering the adverse conditions of the semi-arid region of Pernambuco, such as the seasonality of food supply, high temperatures, and the distance from major grain distribution centers for animal production. In this perspective, the objective was to evaluate the effects of substituting soybean feed, wheat, and corn feed with corn gluten feed in diets containing Mexican Elephant Ear cactus forage on the physicochemical, microbiological, and sensory characteristics of pasteurized whole milk and cheese curd. Eight Holstein cows with a lactation period of 70 to 90 days, an average body weight of 500 kg, and a milk production of 20 kg per day were used and distributed in a double Latin square design (4x4), according to the following treatments: 100% conventional concentrate (CC); 66% CC + 33% corn gluten feed (CGF); 33% CC + 66% CGF; 100% CGF. Milk samples were collected at 6:00 AM and 3:30 PM during data collection days for subsequent pasteurization, physicochemical evaluation, cheese production for each treatment, microbiological analysis, and sensory evaluation. For physicochemical analysis, Dunnett's test was conducted at a 5% significance level, and for sensory analysis, the Friedman test was used. No effect (P>0.05) of CGF on the physicochemical variables of pasteurized milk was observed, despite the positive quadratic behavior for crude protein and decreasing linearity for acidity. The moisture content of the cheese curd was the only variable that differed (P<0.05), showing a negative quadratic effect, 60.09% and 58.38% for the treatments with 33% and 66% substitution with CGF, respectively. The cheese curd produced met the microbiological standards in current legislation. The sensory attributes that differed (P<0.05) were moisture and strange flavor. The highest purchase intention corresponded to the treatment with 33% substitution (P<0.0001). It is concluded that substituting conventional concentrate with corn gluten feed in the diets of lactating cows, despite not differing in the fat content of pasteurized milk and the yield of cheese curd, promotes higher profitability at substitution levels of 33% and 66% with CGF.