Cactus pear mucilage processing enhances corn silage's quality, ruminal degradability, goat kids' performance, carcass traits, and dietary economic profitability

Abstract

The objective of this study was to evaluate the effects of different moisture additives to ground corn grain silage on silage quality, performance, and carcass characteristics of goat kids, and the economic efficiency of the diets. The experimental silos were opened 90 days after silage making and analyzed for chemical composition and aerobic stability. Two experiments were carried out simultaneously, one with 32 non-castrated crossbred male Boer goat kids, weighing on average 16.4 ± 2.5 kg at 6 months of age distributed in a randomized block design with four treatments and eight replications to evaluate performance, carcass characteristics and economic efficiency of the diet; the other with four male sheep weighing 30.4 ± 6.0 kg, fistulated and cannulated in the rumen, and distributed in a Latin square design (4 × 4) to evaluate the rumen degradability profile of the diets. The experimental treatments were a control diet with ground corn grain (GC) and three corn grain silages rehydrated with moisture additives: water (RCSwater), cactus pear cladode mucilage (RCSmucilage) and whey (RCSwhey). The evaluation of the chemical composition of the silages showed that the highest DM, NDF and ash contents were in RCSmucilage, while the lowest was in RCSwater (P < 0.0001), and that there was no difference in NDF content between RCSwhey and RCSwater (P > 0.05). Silage pH was higher for RCSwater and did not differ between RCSmucilage and RCSwhey, while N-NH3 content was lower in RCSmucilage and higher in RCSwater and RCSwhey (P < 0.05). CP, lignin, effluent losses, gas losses, dry matter recovery, lactic acid and propionic acid contents did not differ among silages (P > 0.05). However, acetic acid presented a higher concentration (P < 0.05) in RCSmucilage and lower in RCSwhey. DM and NDF intake, ADG, slaughter weight, total income from carcass sales and income over dietary costs were higher for RCSmucilage when compared to the other silages, and like the control treatment. There was no effect of diets on metabolizable energy and CP intake, feed efficiency, hot and cold carcass weight and yield, cooling losses, loin eye area, and subcutaneous fat thickness of the goat kids carcasses (P > 0.05). The total replacement of ground corn grain in the concentrate by RCSmucilage is recommended in the diet of goat kids, since it promotes better silage conservation, increases DM intake and weight gain, and provides better financial income.