Trial Sites: Fairview Research Farm (PCBFA), North Star (NPARA) & Fort Vermillion (MARA)
Collaborators: Tom Fromme, North Peace Applied Research Association (NPARA)
Jacob Marfo & Sabrina Westra, Mackenzie Applied Research Association (MARA)
From: Peace Country Beef & Forage Association 2016 Annual Report
In the Peace Country region, winter feeding costs make up the bulk of the overall cost of production for cow-calf producers. There are many different traditional ways to extend the grazing season, which include swath grazing and bale grazing. Benefits from extending the grazing season include reducing winter feed costs, improving manure distribution, decreasing fertilizer costs, reducing labour and time spent feeding, increasing soil organic matter content, yardage cost savings and improving animal performance and health. Corn grazing is increasing in the region as an option for producers looking to reduce feed costs per cow per day and to extend the grazing season into the fall and winter months. The objective of this trial was to test corn varieties with low heat unit requirements for suitability for silage/grazing at 3 different locations in the Peace. We have always tested Roundup Ready corn hybrids, but for this trial, we have included some conventional non-Roundup Ready, open-pollinated and organic type varieties. This would enable us to identify and select alter-native corn varieties to Roundup Ready corn types.
The variety trial was carried out at 3 sites (Fairview (PCBFA), North Star (NPARA) & Fort Vermillion (MARA)).
Experimental Design: Randomized complete block design with 4 replicates.
Treatments (corn varieties): a total of 23 corn hybrids/varieties were used. Varieties used consisted of 17 roundup ready corn varieties, 5 conventional hybrids and an open pollinated variety (see Table 2).
Seeding, fertility and spraying information for some of the sites is provided in Table 1.
Measurements taken at harvest: plant height, final plant population, number of ears/plant and forage yield and quality.
Field notes were taken on ear development and kernel stage at harvest.
Results & Discussion
All varieties were similar in plant height, but 2501RR variety seemed to have the potential to grow taller than other varieties. Generally, all varieties grew taller than 6ft (Table 3).
Forage DM yield was significantly highest for X13002S2 (7.26 tons DM/acre). The top four varieties (with up to 6.00 tons DM/acre) were X13002S2, MC4560, PS2210VT2 & PS-Exleaf. Other varieties had DM yields varying from 3.12 to 5.66 tons/acre.
The forage crude protein content was highest for PS-Exleaf (13%). Thirteen (13) of the 23 varieties had 10% or more protein. Generally, all varieties seemed to have enough protein for a gestating beef cow.
The forage energy (%TDN) was generally >65% for all varieties tested in Fairview (Table 4). The top 3 varie-ties with the most TDN were Baxxos RR, MC4560 & OG4680, which had 70% TDN or more. All varieties test-ed have been able to meet the energy (%TDN) requirements of a mature beef cow.
The corn varieties tested all had similar plant height, Venza R seemed to have the potential to be taller than other varieties.
In terms of forage DM yield, all corn varieties had similar yields, but X13002S2 in particular appeared to have the potential to produce higher yields than other varieties.
All varieties had similar forage crude protein content and the protein content varied from 8.12 to 9.72%, indicating that all varieties tested had enough protein for gestating cows in the mid-pregnancy stage. For a cow in the late pregnancy stage, which requires 9% protein, only 13 varieties met the required protein content for this category of cow.
All varieties had similar energy (TDN) content and generally above 65% TDN. The >65% TDN obtained for these corn varieties was adequate for the TDN requirements of mature beef cattle at different physiological stages.
X13002S2 variety had the highest forage DM yield (4.92 tons DM/acre), followed by Fusion (4.42 tons DM/acre), and then E44A02 & Extreme R (with about 4.0 tons DM/acre) in that order (Table 3).
All varieties had similar crude protein content and the protein content (about 9-10%) was enough for what a gestating cow would need at both mid- and late-pregnancy stages.
The forage energy content (TDN) was generally between 62 and 65% TDN for varieties tested.
Across Sites (combined results)
The mean of plant height across the 3 sites was similar for all varieties tested (7-8 ft), but 2501RR seemed to have the potential to grow taller than other varieties.
Forage DM yield was significantly different among varieties tested. X13002S2 significantly had the highest forage DM yield compared to other varieties across the 3 sites.
The forage crude protein content was similar for all varieties across sites (8.6-9.8% CP). This shows that the varieties tested were well within the 7-9% CP needed by a gestating cow, depending on its physiological state (mid- or late-pregnancy stage).
The forage energy (TDN) content was similar for all varieties across sites (66-70% TDN). Generally, the TDN requirements of a dry gestating cow (55-60% TDN) as well as that of a lactating cow (65% TDN) have been met.