Contrasting Standard and Low Lignin Alfalfa in Mixtures with Grasses

This study aimed at comparing the performance of standard and non-GM low lignin alfalfa on forage yield, botanical composition, chemical composition, alfalfa persistence and in vitro total tract NDF digestibility (TTNDFD) when mixed with cool-season perennial grasses. Treatments included standard or low lignin alfalfa (13 kg/ha) seeded in mixtures with tall fescue or timothy (5 and 8 kg/ha, respectively), which were assigned to randomized complete block design with four replications. Experimental plots were seeded in May and were harvested at either the early bud or early flower stages of development of alfalfa for two production years. Forage samples from each plot were chemically analyzed for NDF, ADF, ADL and CP. Alfalfa winter survival were determined by measuring alfalfa stem density in the fall and spring of the following year. Data were analyzed separately for each year using the PROC MIXED procedure of SAS. In the first production year, total forage yield did not differ between treatments. However, in the second year, total yields were higher when both alfalfa types were mixed with tall fescue compared to timothy. Alfalfa yields were higher when mixed with timothy in year one but higher with tall fescue in year two. In both years, yield of tall fescue was higher than that of timothy for both types of alfalfa. We are currently finalizing our chemical analyses and in vitro digestibility analyses (24, 30, 48 and 240h) for TTNDFD determination. 

Key words: alfalfa, low lignin, in vitro digestibility, winter survival.

Published in the proceedings of the Animal Nutrition Conference of Canada 2020. For information on the event, past and future editions, check out https://animalnutritionconference.ca/.