Simple SummaryThe potential supplementation effect of protein-enriched Opuntia (PEO) cladodes, the flat leaf-like stem of cactus species, upon metabolic cues, colostrum, and milk quality, as well as some indicators of kid-to-dam behavioral interactions in crossbred goats under rangeland conditions, was evaluated. PEO supplementation positively influenced dam metabolic status, colostrum quality, and kid-to-dam interactions. Bio-fortified Opuntia cladode supplementation has emerged as an option to improve not only productive behavioral outcomes but also to enhance the sustainability of marginal rangeland goat production systems.The possible effect of protein-enriched Opuntia cladode supplementation during the pre- and post-partum stages (−25 days to +15 days; day 0 = kidding) upon dam–kid metabolic status, colostrum-milk quality, and some behavioral kid-to-dam interaction in goats managed under rangeland extensive conditions was evaluated. Multiparous crossbred goats (n = 30), homogeneous regarding live weight (LW; 55.9 ± 1.03 kg) and body condition score (BCS; 2.5 ± 0.2 units), were randomly assigned to (1) protein-enriched Opuntia (PEO; n = 10; 29.8% crude protein (CP), 2.2 Mcal ME kg−1), (2) non-enriched Opuntia (NEO; n = 10; 6.4% CP, 2.1 Mcal ME kg−1), and (3) control (CON; n = 10, non-supplemented). The PEO and NEO goats were individually supplemented with Opuntia cladodes (250 g day−1; 09:00–10:00 a.m.; 25 days pre- and 15 days post-partum); then, all groups grazed in a marginal rangeland (10:00 a.m. to 06:00 p.m.). LW, BCS, and blood samples to quantify serum glucose (GLU) levels were collected weekly from day −25 up to day +15 in both dams (pre- and post-partum) and kids (post-partum). At 4 h and 8 h post-partum, kid-to-dam behavioral tests were performed; approaches (APRO, units), animal-to-animal contact (ACONT, s), latency-to-contact (LCONT, s), and high (HPB) and low (LPB) bleats were registered. The response variables LW (58.2 ± 3.5 kg), GLU from does (66.4 ± 3.3 mg/dL), colostrum fat (12.3 ± 1.15%), non-fatty solids (20.9 ± 2.1%), density (64.4 ± 7.0%), and protein (8.1 ± 0.8%), as well as milk density (31.2 ± 1.7%) and protein (3.9 ± 0.3%), favored the PEO group. Moreover, the dam-to-kid 4 h LPB (34.5 ± 4.6 frequency), as well as kid-to-dam 8 h LCONT-own (100 ± 35.5 s) and LPB (25.2 ± 6.9 frequency) also favored the PEO group. To conclude, peripartum supplementation with protein-enriched Opuntia cladodes emerged as a key alternative to enhance the dam–kid metabolic status, to improve colostrum quality and some milk components (density and protein), as well as to expand the kid-to-dam bond in goat production systems under marginal extensive conditions.