Effect of feeding mechanically processed alfalfa silage on production performance of mid-lactation dairy cows

Authors: KENNEDY, KATHERINE - Oak Ridge Institute For Science And Education (ORISE); PINTENS, DAVID - University Of Wisconsin; Kalscheur, Kenneth; SHINNERS, KEVIN - University Of Wisconsin; FRIEDE, JOSHUA - University Of Wisconsin; DIGMAN, MATTHEW - University Of Wisconsin

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2024
Publication Date: 1/1/2025
Citation: Kennedy, K.M., Pintens, D.A., Kalscheur, K., Shinners, K.J., Friede, J.C., Digman, M.F. 2025. Effect of feeding mechanically processed alfalfa silage on production performance of mid-lactation dairy cows. Journal of Dairy Science. https://doi.org/10.3168/jds.2024-25288.
DOI: https://doi.org/10.3168/jds.2024-25288

Interpretive Summary: Dairy cow diets formulated with high levels of forage may limit intake resulting in lower milk production. Development of new processing techniques for forages may help improve their digestibility and, consequently improve the production performance of lactating dairy cattle. The objective of this study was to determine the effects of an intensive mechanical processing technique applied to wilted alfalfa silage on feed intake, feeding behavior, and lactation performance in lactating dairy cows when fed as part of a total mixed ration. Alfalfa processed by the intensive mechanical processing method improved nutrient digestibility of alfalfa silage in dairy cattle. Mid-lactation dairy cows fed the mechanically processed alfalfa silage resulted in greater energy-corrected milk yield while maintaining dry matter intake, consequently improving gross feed efficiency when compared with mid-lactation cows fed a conventionally chopped alfalfa. This study demonstrates to dairy producers and nutritionists that mechanically processed alfalfa enhanced fiber digestibility resulting in improved gross feed efficiency in mid-lactation dairy cows. This processing method may prove to be a useful tool in diet formulations and feeding strategies to improve performance of dairy cows fed high forage diets.

Technical Abstract: Improving the production and efficiency of dairy cattle is a complex topic comprised of several facets of research. One such area involves improving the processing methods of feedstuffs to improve the digestibility and utilization of said feedstuff. Our objective was to determine the effect of an intensive mechanical processing technique applied to wilted alfalfa silage on dairy cow performance when fed as part of a total mixed ration. Thirty-six mid-lactation Holstein dairy cows (primiparous and multiparous) were fed diets of similar composition (28.5% alfalfa haylage, 31.2% corn silage and 40.3% concentrates) that differed by pre-ensiling processing technique of alfalfa silage over a 6-week experimental period in a randomized complete block design. Treatments were alfalfa either conventionally chopped (CON) or mechanically processed (MP). Neither body weight, change in body weight, body condition score nor change in body condition score differed between treatment diets, but primiparous cows were lighter than multiparous cows. Apparent dry matter, neutral detergent fiber (NDF), acid detergent fiber, and crude protein digestibility were greater in MP compared with CON. Both dry matter intake (DMI) and DMI per unit of metabolic BW (mBW; BW0.75) were lower in MP compared with CON during week 5. Furthermore, forage NDF intake and forage NDF intake/mBW were lower or tended to be lower in MP compared with CON during wk 5. Milk yield did not differ between MP and CON, but milk fat yield and content were higher in MP compared with CON. Consequently, 4% fat-corrected milk and energy-corrected milk (ECM) were greater in MP compared with CON. Gross feed efficiency (ECM/DMI) was greater in MP compared with CON during weeks 5 and 6. Our results suggest that feeding a mechanically processed alfalfa silage enhanced fiber digestibility and subsequently improved dairy cattle gross feed efficiency in mid-lactation dairy cattle. Further research is needed to elucidate physiological responses and practicality of implementing this processing method in atypical production setting.