ABSTRACT
Forage cactus as a modulator of forage sorghum silage fermentation: An alternative for animal feed in drylands

Danillo Marte-Pereira1, Juliana S. Oliveira2, Francisco N. Sousa-Santos1, Alberto J. Silva-Mac?do2*, Paloma G. Batista-Gomes2, Liliane Pereira-Santana3, Evandro S. Silva2, Gabriel F. Lima-Cruz4, Alexandre Fernandes-Perazzo5, and Edson Mauro-Santos2
 
The rapid conversion of water-soluble carbohydrates in sorghum (Sorghum bicolor (L.) Moench) into lactic acid causes an abrupt decrease in silage pH, promoting alcoholic fermentation and aerobic deterioration. Despite the use of microbial and chemical additives, the results remain inconsistent. Mixing sorghum with cactus pear (Nopalea cochenillifera (L.) Salm-Dyck) can improve the stability and fermentative characteristics of silage. The aim of this study was to determine the ideal level of cactus pear that provides a good microbiological profile, as well as decreases losses during the ensiling process of mixed silages of cactus pear and sorghum. The treatments were composed of levels of cactus pear in the sorghum ensilage (0%, 25%, 50%, 75% and 100% cactus pear on a natural matter basis in the mixture), with four replicates each. It was found a quadratic effect (p < 0.05) on lactic acid bacteria counts, DM recovery and gas losses, with maximum estimated values of lactic acid bacteria and DM recovery in the levels of 51.8% and 33.5% of cactus pear, respectively, and minimum value of gas losses in the level of 37.9% of cactus pear in the silage. An increasing linear effect (p < 0.05) was observed on silage aerobic stability, contents of ether extract and non-fiber carbohydrates. When using cactus pear in the production of mixed silages with sorghum, it is recommended 50% cactus pear in the mixture, as it optimizes DM recovery and aerobic stability of the silages.
Keywords: Aerobic stability, dry matter recovery, lactic acid bacteria, losses, yeasts.
1Universidade Federal do Maranhão, Departamento de Zootecnia, 65500-000, Chapadinha, Maranhão, Brasil.
2Universidade Federal da Para?ba, Departamento de Zootecnia, 58397-000, Areia, Para?ba, Brasil.
3Universidade Federal Rural do Pernambuco, Departamento de Zootecnia, 52171-900, Recife, Pernambuco, Brasil.
4Universidade Federal de Vi?osa, Departamento de Zootecnia, 36570-900, Vi?osa, Minas Gerais, Brasil.
5Universidade Federal do Piau?, Departamento de Zootecnia, 64049-550, Teresina, Piau?, Brasil.
*Corresponding author (macedoajs@gmail.com).