Effects of Olive Cake and Cactus Cladodes as Alternative Feed Resources on Goat Milk Production and Quality

In the Mediterranean area, the olive cake (OC) and cactus cladodes (CC) are two alternative resources widely available that could be used for ruminants’ feeding. The objective of this study was to evaluate the effects of OC and/or CC diet incorporation on the production performance and quality of goat milk. Forty-four lactating goats were randomly allocated to four groups. The control one (Co) received a conventional feed. Test groups (TOC; TCC and TOC+CC) received 20% OC, 30% CC, or 15% OC and 20% CC, respectively, on concentrate dry matter basis. Over three months, milk production was evaluated, and samples were collected to analyze the milk quality. No significant differences were observed between control and test groups for daily milk production, yield, composition and acidity. In milk fat, OC incorporation increased C18:1n-9, mono-unsaturated (MUFA) and n-9 fatty acid (FA), and decreased 9t-C18:1 and poly-unsaturated FA (PUFA) (p < 0.05). Significantly highest contents of C15:0, C18:1n-9, and C21:0, and lowest levels of C4:0, 9t-C18:1, 6t-C18:2, C20:0, and PUFA were obtained with cactus cladodes administration (p < 0.05). The TOC + CC diet reduced C4:0, 9t-C18:1, 6t-C18:2, C22:6n-3, and PUFA proportions, and increased C18:1n-9, MUFA/PUFA, and thrombogenic indexes. The incorporation rates of OC and CC that could reach 20% and 30%, respectively, had no major negative effects on milk production performance, composition, and quality. Thus, they could be introduced in the diets of lactating goats.