Inclusion of Novel Olive Pulp: Impacts on Nutrient Digestibility, Rumen Fermentation, and Dairy Goat Performance

TL;DR

This study shows that adding olive pulp to dairy goat feed improves nutrient digestion and milk quality without harming performance.

Contribution

The study introduces a novel olive pulp as a viable feed ingredient for dairy goats, demonstrating its benefits on digestion and milk composition.

Findings

Olive pulp inclusion increased dry matter, organic matter, and fat digestibility in goats.

Milk from goats fed olive pulp had higher protein and conjugated linoleic acid levels.

Nitrogen excretion decreased with olive pulp inclusion, suggesting better nitrogen utilization.

Abstract

The use of agro-industrial by-products in animal feed is gaining relevance in the livestock sector. This study aimed to characterize and assess the effects of incorporating a novel olive pulp type into the diet of Murciano–Granadina goats, focusing on parameters such as ruminal fermentation, nutrient digestibility, energy and nitrogen metabolism, and milk production and quality. To achieve this, two in vivo trials were conducted to evaluate the impact of including olive pulp at a 12% inclusion rate in the concentrate. The results suggest that olive pulp can serve as an effective alternative feed ingredient for ruminants, offering promising potential for livestock nutrition.

In light of the exponential rise in feed costs within the livestock sector, the scientific research and valorization of novel agro-industrial by-products have essential strategies in animal nutrition. The overall objective of this study was to characterize and evaluate the inclusion of a novel olive pulp included at 12% of the concentrate on a dry matter basis in the diet of Murciano–Granadina goats to assess its effects on ruminal fermentation, nutrient digestibility, energy and nitrogen metabolism, and milk yield and composition. Two experiments were conducted, taking into account two groups (control group, CTL, and an experimental group) with the inclusion of 12% olive pulp in the concentrate (OPD): one in vivo trial in metabolic cages (n = 10 nulliparous female goats (34.1 ± 0.70 kg) per treatment) was conducted to evaluate digestibility, nitrogen balance, and energetic utilization; and a second on-farm production trial (n = 24 adult dairy goats (53.6 ± 1.14 kg) per treatment). The results showed no significant differences in energy balance or microbial protein synthesis between CTL and OPD (p > 0.05). However, the OPD exhibited higher digestibility of dry matter (71.2 vs. 68.8%; p = 0.028), organic matter (70.8 vs. 68.4%; p = 0.026), and crude fat (85.9 vs. 83.4%; p = 0.024), but lower crude protein digestibility (70.7 vs. 73.4%; p = 0.012) and nitrogen excretion (1.24 vs. 1.44 g/kg0.75; p < 0.001). Additionally, ruminal butyrate concentrations were higher in OPD goats (13.5 vs. 11.3 mol/100 mol of total short-chain fatty acids; p = 0.020). Although milk yield remained unaffected, the OPD exhibited higher milk protein (4.17 vs. 3.79%; p = 0.036) and conjugated linoleic acid (0.620 vs. 0.400%; p < 0.001) concentrations compared to CTL. These findings demonstrate that the inclusion of 12% of the novel olive pulp in goat concentrate is a viable feeding strategy that maintains productive performance while enhancing the nutritional quality of milk.