Including up to 15% pomegranate by-product in the diet does not affect physiological parameters in dairy goats

This experiment aimed to study the effect of the inclusion of different proportions (0, 5, 10, and 15% dry matter) of ensiled pomegranate by-product in dairy goat diets on dry matter intake (DMI), water intake (WI), milk yield, and reference physiological parameters. A total of 80 goats were selected and divided into 8 groups of 10 animals each (4 treatments × 2 plots) with homogeneous physiological characteristics. After a pre-experimental blood and milk sampling, four additional milk samplings were taken fortnightly, and one more blood sample was collected at the end of the experiment. Milk yield (Lactocorder®, WMB AG, Switzerland), milk composition, and somatic cell count (SCC) (CombiFoss™7DC, Foss, Denmark) were analyzed. Hematological variables were evaluated using the ElementHT5 analyzer (SCILVET, Spain), and plasmatic metabolites were analyzed with the rapid diagnostic disk “Diagnóstico II” for ElementRC3X (SCILVET, Spain). Statistical analysis was performed using a mixed linear model (Proc. Glimmix, SAS v9.4), considering the covariate effect in pre-experimental sampling, treatment (4 levels), experimental sampling (4 levels), and their interaction (16 levels), with plots nested within treatments. For blood samples, only two levels of sampling were considered. The goat was considered the random effect. Regarding productive indices, the sampling and covariate were significant (P < 0.05). For DMI and WI, treatment and sampling were significant, while their interaction was only significant for DMI. Concerning physiological parameters, only sampling was significant but not biologically relevant. A decline in milk yield was observed, corrected when considering its composition (FPCM), along the experiment. DMI was lower in the highest inclusion treatment (15%). WI was inversely proportional to pomegranate inclusion. Feed efficiency had no significant effect on milk yield. SCC declined in the highest inclusion treatments (10% and 15%). No physiological parameters showed significant changes due to the new diet. Pomegranate silage can be included by up to 15% DM in dairy goats' diets short-term, although long-term experiments are needed. This study was supported by the Valencian Government (CIAICO/2021/301).