Forage Yield and Quality of Forage Oat Varieties Harvested at Two Stages of Maturity

Collaborators: Smoky Applied Research Association (SARDA) & Fevang Farms, High Prairie

Research Coordinator: Dr. Akim Omokanye

From: Peace Country Beef & Forage Association 2011 Annual Report

Beef cattle producers commonly use annual cereals for silage, greenfeed and swath grazing. In Alberta, oats account for more than 40% of total annual greenfeed production. Annual crops can provide emergency or supplementary forage in all parts of the Peace. They are easy to seed, establish quickly and can provide pasture later in the growing season when perennial production is decreasing and demand is at its highest. The objective of this project is to examine the effects of maturity of forage yield and quality of forage oat varieties.

Methods

The trial was done in collaboration with SARDA. The plots were located at Fevang Farms near High Prairie on canola stubble. Prior to seeding, the plots got a pre-seed weed control operation. The treatments were replicated 4 times, using a randomized complete block design to lay out the small plots (10 m long, 6 rows at 9 inch spacing). Nine forage oat varieties were seeded on May 20, 2011 with a plot drill. The site was harrowed in the spring and each variety seeded at 250 plants/m2 (actual weight based on thousand kernel weight and germination). Fertilizer was applied at 50 lb N/ac, 30 lb P2O5/ac, 20 lb K2O/ac, 30 lb S/ac (using seed placed 11-52-0, and side banded 46-0-0, 20-0-024, and 0-0-60). Herbicide application: June 22, 0.18 L/ac Prestige A + 0.8 L/ac Prestige B.

The nine forage oat varieties seeded were: CDC Baler – forage oat, very leafy. Everleaf – new forage oat, extremely wide leaves. Foothills – older forage type variety, finer stemmed, tall growing, high palatability. AC Jordan – new feed/milling/forage oat, high silage and grain yield, large seed size. AC Morgan – high yielding, later maturing milling oat, commonly used for silage or greenfeed. AC Mustang – feed oat. Murphy – forage oat, high silage yield, stands tall. Waldern – feed oat, high silage yield. SO1 – bred in Saskatchewan, SO-I (CDC Super Oats, variety number one) is a new forage/feed oat variety. It is excellent feed oat for backgrounding cattle, very digestible, high fat content, does not need to be rolled. In order to determine the maturity stage at harvest that optimizes the yield and quality of the oat varieties for swath grazing or greenfeed systems, the oats were harvested at two maturity stages (late milk and dough). For forage DM yield estimation and feed quality tests, the late milk stage, forage was harvested August 5, and for the dough stage, harvesting was done August 26.

Results

Forage Yield

The forage DM yields of all oat varieties increased as cutting was delayed from the late milk stage until the dough stage (Figure 1). The mean forage DM yields across the nine oat varieties were respectively 7586 and 8572 lb/acre for late milk and dough stages. When cut at the late milk stage, forage DM yields were

similar and highest for both Foothills and Warden (>8000 lb/acre) and lowest for Everleaf (6654 lb/ acre). For the dough stage, DM yields were higher for Warden, Foothills and Mustang (>9000 lb/acre) and least for Jordan (7490 lb/acre). When pooled across the two stages of maturity at cutting, the average forage DM yield was in the following order: Warden> Foothills > Mustang > SO-I > Murphy > Baler > Morgan > Everleaf > Jordan.

Forage Quality

Forage quality values of oats harvested at different maturity stages are presented in Figures 2 & 3 and Table 1. Winter fed crude protein is an incurred and expensive cost by producers for the maintenance, health, and production of their cows. Information on oats producing forage/feed and their quality would be important in determining the value of oats greenfeed or silage and could be used in the calculation of winter feed protein supplements. When averaged across the 9 oat varieties, forage CP content of was significantly higher at the late milk stage (9.17%) than at the dough stage (5.66%). For the late milk stage, SO-I oat had the highest CP (10.55%) and Jordan oat had the least CP with 7.24% (Figure 2). When harvesting was delayed till the dough stage, Everleaf had the most CP (7.20%), while Mustang had the least CP (4.54%).

Considering the suggested Ca and P mineral allowances for beef cattle, all forage oat varieties were generally in allowable Ca and P contents regardless of stages of maturity at cutting. The mean TDN was higher for the dough stage (61.94%) than the late milk stage (55.49%). Generally, for each oat variety, cutting at the late milk stage gave slightly lower TDN (3-8% less energy) than cutting at the dough stage (Figure 3). At the late milk stage, TDN varied from 52.78% for Murphy to 57.97% for SO-I. But for the dough stage, TDN values varied from 59.52 % for Baler to 64.61% for Jordan. For all the forage oat varieties examined, the dough stage had lower ADF and NDF contents than the late milk stage (Table 1). At both stages of maturity, SO-I oats consistently had a lower ADF content.

What effect does harvesting time have on forage yield and quality?

As with most forage crops, there is a yield – quality trade off as small grains mature from boot to dough maturity stages. Timing of the cereal forage harvest is critical to obtain the desired forage quality. The window for harvest is often small for any given stage of maturity and desired forage quality. In the present study, the highest quality was when the harvested forage oat was in the late milk stage, but higher forage DM yields and energy harvested per acre occurred at the dough stage.