Cactus cladode juice as a molasses replacement in urea-multi-nutrient blocks: effects on intake, milk yield, composition, and estimated enteric methane emissions in crossbred dairy cows in dryland Waghimra, Ethiopia.

Abstract

Molasses is an important component of urea-multi-nutrient blocks (UMMBs), but its high cost and inconsistent availability can limit their use in dryland livestock systems. This study evaluated the effects of replacing cane molasses with cactus cladode juice in UMMBs on intake, milk production, milk composition, and estimated enteric methane emission intensity in lactating crossbred dairy cows. Sixteen mid-lactation local Zebu × Holstein Friesian crossbred cows were assigned to four treatments in a randomized complete block design based on initial milk yield and body weight. Treatments consisted of UMMBs with 0, 50, 75, or 100% replacement of molasses with cactus cladode juice. Following 14 days of adaptation, data were collected for 60 days. Dietary treatments affected UMMB intake, milk yield, and milk composition (P < 0.001). The 50% replacement treatment recorded the highest UMMB intake, milk yield, and UMMB utilization efficiency, whereas milk composition differed only slightly among treatments. Estimated daily enteric methane production increased with cactus inclusion, while estimated methane emission intensity per kilogram of milk decreased. These findings suggest that cactus cladode juice has potential as a locally available alternative to molasses in UMMBs under dryland conditions. However, findings are preliminary because of the small sample size and short experimental period, and direct methane measurements are required for confirmation.