Ryegrass Cultivars Compared for Cattle Growth

In 2016 Pasture Genetics in Australia conducted research into the growth rates of cattle on three commonly used perennial ryegrass cultivars.

The research was conducted to verify the common assumption that dry matter production in plot trials determines the relative profitability of cultivars.  This assumption is based on another assumption; that animals grow at the same rate regardless of variety.

The trial was conducted on 6 ha divided into 12 sections.  30 steers with an average weight of 334 kg were split into mobs of 10 and grazed simultaneously on each variety for 12 weeks (21 August to 13 November).  Each mob had equal time grazing each of the varieties.

Caption; Aerial photo of the research centre and trial paddock.

Also measured during the grazing trial were pasture production and quality.  Ansa AR1 and Trojan NEA2 produced more dry matter in the first two grazing rotations Fig. 1), with One 50 AR37 picking up at the end of the trial to be about the same as Ansa AR1 and more than Trojan NEA2.  All varieties had similar energy content, but Ansa AR1 had higher protein and digestibility and lower NDF than the others.

Caption; The cattle weighing facility at the research centre.

Figure 1.  Average pasture production (kg DM/ha/day).

Ansa AR1 consistently achieved a higher level of weight gain throughout the trial (Fig. 2).

Figure 2.  Total average weight gain (kg/animal/day).

Source;  Perennial Ryegrass Grazing Trial 2015, Penfield Station Agronomy Field Days 2016, Pasture Genetics.