Spring Pasture Management for Cool-Season Grasses

Published on Fri, 01/11/2019 - 2:42pm

 Spring Pasture Management for Cool-Season Grasses

 By Michael Cox

 The arrival of warmer Spring weather is just around the corner and with it comes the prospect of finally letting cattle back to pastures after the winter season. On many ranches, Spring can be a particularly busy time of year, so now is a good time to take stock of pasture quality and quantity and plan some management strategies around utilizing the new grass growth when it comes.

What grass is on the ranch?
An early Spring grass-walk around the ranch is an absolute necessity to figure out what amount of grass is in each pasture, the type of grass (cool or warm season) and any fencing that needs to be repaired before ‘the rodeo’ of letting cattle back to grass begins. During the grass-walk it can be useful to take note of which cool season pastures look healthiest and which paddocks or fields typically have the best soil fertility and Spring growth rates.

Watch the regrowths
The aim of the first rotation is to graze an increasing proportion of the farm daily and ration out the grass until growth rates take-off and we can begin the second rotation. When growth is slow in Spring, the rule of thumb is to ‘go-slow’, and only graze a small area of the farm daily. As the weather warms up and growth increase a larger area can be grazed everyday. Essentially, the first rotation is all about managing regrowths; the rotation can be as slow as 90 days at the start of season, as it could take 90 days before that paddock is ready for grazing again. As Spring progresses, and regrowths grow more rapidly, the rotation length can be dropped down to 25 to 30 days. Depending on the weather conditions and longer term forecast, the rotation can be slowed down or speeded up, if regrowths on the first paddocks grazed are expected to be ready for second grazing later or earlier than anticipated. Protecting these precious regrowths is key to the system, and is only possible of fields are rotationally grazed and swards rested after an intense grazing period. Hay or other supplement can be added or taken from the diet based on the amount of grass available in each field.

If you usually set-stock the farm in Spring, now could be the perfect opportunity to consider rotationally grazing some or all of the pastures this Spring. The benefits of rotational grazing are well documented. In many cases, rotational grazing can double grass utilization from 35% under set-stocking to 70%. This extra grass consumed is particularly valuable in Spring as it reduces the amount of hay fed to cattle. The phenomenal benefits and economic improvements from rotational grazing are too good to ignore, especially given the current cattle market profitability levels.

Grazing low
High soil fertility pastures and cool season grasses offer the best regrowth response early in the season. If grazed early, these pastures will have adequate time to accumulate fresh regrowth and be ready for grazing again at the second rotation. Cool season grasses can have a surprising amount of feeding value in Spring. Even if the grass looks yellow and frost burnt, it is still of excellent nutritional value, far better than hay. The dry matter of this grass will be very high after frost burn, sometimes greater than 30%, so every mouthful of this frost burnt grass offers huge amounts of dry matter to cattle, even if it visually looks like there’s only a few inches of grass available. With this type of Spring grass it is a case of ‘use it or lose it’, as the frosted grass will rot later in the Spring when the weather warms up. Cool season grasses must be grazed tight in Spring, down to 2 inches. This creates many benefits; the old dry grass is utilized before it rots away, the base of the sward is ‘cleaned-out’ and left ready to grow fresh lush regrowth, sunlight is allowed down to the base of the plant to boost new growth, the growing point for new regrowth is set low- so there will be very little poor-quality stem in the second grazing round. Research from New Zealand suggests that grazing cool season grasses tight in Spring is crucial. When these grasses are not grazed low, the total amount of regrowth for the second rotation will be less than if the sward is properly ‘cleaned-out’.
Generally, little or no Nitrogen fertilizer is needed in Spring, as producers often find themselves in a huge surplus of grass in late Spring, and any extra N will only exacerbate this problem. However, it may be useful to consider applying a small amount of N to some of the best stands of cool season grasses after first grazing. The response rate from N can often be greater than 15:1 for every lb of N applied. A small amount of N applied just after first grazing can help kickstart regrowths, which in turn will allow producers to start the second rotation earlier; and therefore harvest more grass in the most economical way; straight down the cow’s throat.