Babassu coconut plus urea supplementation in diets of lactating goats: Effects on intake, feeding behavior, digestibility, and milk yield, composition, and fatty acid profile

This study aimed to determine the optimal inclusion level of fresh ground babassu coconut (GBC) combined with urea as a substitute for corn and soybean meal in diets for lactating crossbreed Saanen goats. Eight multiparous goats in mid-final-lactation and average body weight 40.2 ± 1.92 kg were assigned to two simultaneous 4 × 4 Latin squares, with four inclusion levels of GBC (0, 8, 16, and 24% of total dry matter (DM), corresponding to 0, 20, 40, and 60% of concentrate DM; GBC partially substituted ground corn), and with urea added to maintain available N. Increasing dietary GBC promoted a linear decrease (P < 0.0001) in DM intake (from 2.70 to 1.02 kg/day at 60% GBC). Intakes of crude protein (CP), ether extract (EE), neutral detergent fiber, corrected for protein and expressed exclusive of residual ash (aNDFom), and non-fibrous carbohydrates (NFC) also declined linearly (P < 0.05). Rumination time increased between 0 and 20% GBC addition (P = 0.001), but then decreased till 60% GBC. In contrast, idling time decreased between 0 and 20% GBC, and then increased till 60% (P = 0.047). Eating rates (g/h) decreased linearly (P < 0.05), and rumination rates decreased till 40% GBC addition, with a small increase from there till 60% addition (P = 0.049 for DM and P = 0.045 for aNDFom). Dry matter digestibility dropped from 60.1% (control) to 48.4% at 60% GBC addition, and CP digestibility from 66.5% to 49.3% (P < 0.0001). Organic matter (P < 0.0001), EE (P = 0.0196), and aNDFom (P < 0.0001) also reduced linearly. Milk yield, energy-corrected milk and milk fat (g/d) decreased linearly (P < 0.05) with increasing GBC level, with total corrected milk yield decreasing from 591 to 411 g/day. However, milk fat (%) increased from 3.47% to 5.07% and feed efficiency increased linearly, primarily with the two highest GBC inclusions (P < 0.0001). Other milk components (protein, lactose, minerals) were unaffected (P > 0.05). Milk fatty acid (FA) profile was markedly altered. Short- and medium-chain FA (C4:0–C14:0) decreased linearly, while C18:0 and C18:1 cis–9 (oleic acid) increased significantly (P < 0.01), raising monounsaturated fatty acids (MUFA) content from 28.8% to 44.1% and reducing total saturated fatty acids (SFA) from 68.4% to 51% in fat milk due GBC inclusion. Consequently, the MUFA: SFA ratio doubled (0.42 to 0.86), the hypo-: hypercholesterolemic (h: H) index increased from 0.51 to 1.38, and atherogenicity and thrombogenicity indices decreased (P < 0.01). Desirable fatty acids [DFA index = MUFA + PUFA (polyunsaturated fatty acids) + C18:0] increased 39.4% to 65% due to GBC addition. Stearoyl-CoA desaturase [SCD–Δ–16 = C16:1 cis –9/(C16:0 + C16:1 cis –9) and elongase activities increased linearly (P < 0.05), whereas SCD–Δ–18 (C18:1 cis –9/(C18:0 + C18:1 cis –9)] decreased linearly with rising levels of GBC (P < 0.05) and SCD–Δ–14 [C14:1 cis –9/(C14:0 + C14:1 cis –9)] showed a quadratic effect (P < 0.001) with GBC addition. Inclusion of GBC in the diet of dairy goats reduces intake, digestibility and milk yield, but improves milk fat quality. Hence, its use as an energy source for partially replacing corn would depend on the orientation of the farm: as an example, if the production of cheeses of high-quality is aimed, its introduction in the diet in small proportions (≤8% total dietary DM), combined with urea supplementation (2.0 g/kg total DM), could be advisable depending on GBC cost and availability. • The inclusion of ground babassu coconut (GBC) in the diet increased fat content of goat milk. • High GBC (40 and 60%) inclusion compromised intake, digestion, and goat milk production. • GBC boosted monounsaturated (MUFA) and lowered saturated fatty acids (SFA) in milk. • GBC improved milk lipid health indices despite reduced production.