Choosing the best kale

Stock can and will gain weight on kale, but need plenty of leaf and good forage quality. The days of choosing a kale cultivar based simply on dry matter (DM) yield are well behind us. Results from a Canterbury kale study (Westwood et al 2014)* can help identify the best kale for your property.

The study ran from May to September 2013 and compared the forage yields, leaf percentages and feed quality values associated with four kale cultivars: Regal®, Gruner, Kestrel and Rawera. Kale cultivars were sampled on a monthly basis for nutrition value of plant components (stem and leaf).

* Westwood CT, Cutts M, Russell R, O’Brien K (2014). Effect of timing of harvest on nutritive value, and dry matter yield of four cultivars of kale (Brassica oleracea L. Var. acephala). Proceedings of the New Zealand Grasslands Association (in press).

Trial results

Dry matter yield: Regal® and Gruner yielded significantly more DM than Kestrel or Rawera kales. A late-winter flush of leaf growth lifted yields of Regal and Kestrel, but not Gruner or Rawera. For the best of both worlds (yield and leaf), choose Regal.

Leaf percentage: Regal and Kestrel produced more leaf compared with Gruner or Rawera. The difference was very obvious by latewinter. For a leafy crop, particularly in late winter, choose Regal or Kestrel.

Metabolisable energy (MJME) content: Kestrel contained significantly more energy (MJME/kgDM) and less neutral detergent fibre (NDF) than the other kale cultivars. While Kestrel recorded a lower DM yield, its energy density lifted the MJME yield per hectare to levels comparable with other cultivars.

Sheep grazing Cleancrop™ Firefly kale in Southland.

Stem quality: Kestrel had the highest quality stem, with 13.0 MJME/kgDM for top stem and 11.6 MJME for stem base. The results indicated Rawera has a very low quality stem base (8.7 MJME/kgDM), almost a 3.3 reduction in the MJME value recorded for top stem.



DM yield: If the amount of feed available is your key requirement, choose Regal® or Gruner. Both kale cultivars produce a high DM yield; however, Regal had a flush of new leaf growth in late winter while Gruner lost leaf. When late-winter leaf and yield is needed, choose Regal over Gruner.

Quality: When stock liveweight gain and/or body condition score is your priority, choose Kestrel. A high quality stem and good leaf percentage allows Kestrel to provide a premium feed option. When quantity and forage quality are equally important, Regal’s high leaf percentage and high DM yield delivers on both, optimising performance of your stock.

Leaf percentage of four kale cultivars during winter 2013

Cleancrop™ Firefly kale

Firefly kale is a high yielding, intermediate-height kale with a high leaf-to-stem ratio. Excellent crop utilisation by animals due to single plant selection for soft stems during the plant breeding process. Firefly is the first kale cultivar available in the Cleancrop™ Brassica System bred to have a herbicide resistance trait, which allows the application of Telar® herbicide at both pre- and post-emergence for excellent weed control.

  • High yielding, intermediate-height kale
  • High leaf-to-stem ratio with very good late winter leaf percentage
  • Excellent crop utilisation due to selection for soft stems
  • Very good winter hardiness and excellent pest and disease tolerance
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