Dalrymple uses his experience and knowledge as well as some professional nutritional advice to plan and feed an optimal ruminant diet to achieve consistent and controlled weight gain.
“The first aim is to get the basic components of the diet right,” says Dalrymple, who recognises the differing contribution of starch, protein, and roughage to rumen function and animal performance.
“If the balance is right, the rumen is functioning well and there is little feed wasted.”
All of this contributes to an efficient and cost effective feeding system with the ability to manage animal growth rates.
Dalrymple explains that he uses one of two main diet formulations depending on whether the cattle are being finished to be killed off the feed pad or whether they are being wintered under contract.
The finishing diet is based around growth rates of 1.8kg/day and consists of high quality, low bulk feeds to maximise intake. The aim is to reach a kill weight of 600-620kg to supply the winter beef market – this is best achieved on a diet of high quality protein and starch (energy).
To achieve this, Dalrymple sources locally grown maize silage and maize earlage. Maize silage has a relatively consistent starch content and supplies some roughage while the maize earlage, typically has an even higher starch content with comparatively low roughage. Lucerne silage contributes the protein component of the diet. These three main components are mixed onfarm according to the pre-determined energy and protein requirements of the cattle.
The key requirement of the feeds for the finishing diet is relatively low roughage. This prevents intake being limited by rumen capacity, and allows the animals to achieve the high nutrient intakes required to meet their high growth rate targets.
The wintering diet targets cattle growth rates of 0.8kg/day, which are achieved by feeding a diet based on ryegrass – white clover silage and maize silage.
“These feeds are readily available, relatively cheap and good quality,” explains Dalrymple.
Most of the maize silage is grown and stored onfarm and, as in the finishing diet, valued for its relatively consistent energy content. However, in contrast to the finishing diet extra roughage is added to provide bulk and slow down fermentation in the rumen.
“Between 10-25% of the diet is straw depending on the need to limit or improve growth rates,” says Dalrymple. “The added roughage means that the cattle are full and ruminating on a consistent basis, which is important for growth as well as heat production and rumen function.”
Warm welcome
Roger Dalrymple’s understanding of diet components and rumen function, and his ability to incorporate this knowledge into the feed pad system, is undoubtedly a key part of its success. The results of this success are shared by the farmers of the stock Dalrymple winters under contract. Richard Chrystall, farm operations at Atihau-Whanganui Incorporation, is one such farmer.
“The cold and exposed climate [on the Central Plateau] contributes to high maintenance feed requirements for stock over winter – growing cattle on winter brassicas is costly weight gain,” says Chrystall.
The opportunity to winter stock in a warmer climate takes the pressure off winter feed demand and allows greater control of cattle growth rates over that time.
Last winter a total of 3000 Atihau cattle were wintered on the feed pad – 1200 weaners, 1300 R2 steers, and 500 R2 heifers. After 100-120 days of Waitatapia’s relatively mild winter the cattle returned to farm land on the Plateau to meet the spring flush.
It is important that this transition is as smooth as possible as any growth check upon returning to pasture immediately reduces the systems efficiency. Chrystall reports that “stock return to pasture in forward condition with optimum rumen capacity [which] is essential for growing cattle to finishing weights to meet peak schedule prices.”
Quality a constant
Compared to a pasture-based system, Roger Dalrymple’s feed pad is high input, and therefore high cost, but it is made most efficient by exercising forward planning and feed budgeting. Dalrymple plans and sources his feed supply a year out from when it is required.
“Planning reduces the cost of gain because you can source the feed when it is cheapest.
Roger Dalrymple uses a carefully balanced diet to winter cattle on his feed pad near Bulls.
“It is also crucial to source the feed as close to the feed pad as possible as cartage costs can quickly accumulate, increasing the cost of gain.”
Although keeping costs down is essential, Dalrymple maintains that fluctuations in feed costs generally do not change his purchase choice. He sees it as more important to stick with feeds of consistent quality to supply the optimal balance of protein, starch, and roughage – his experience has shown that this will provide consistent growth.
Apart from liveweight gain itself, there is another simple way of knowing whether the diet is supplying the right quantities of the three major nutrients – a quick assessment of the cattle dung is a simple form of feedback on the efficiency of rumen fermentation.
Dalrymple explains that “too much roughage in the dung, grain appearing in the dung, or a runny consistency can be indications that things are out of balance.” This allows adjustment to be made to feed formulations within 24 hours.
It has taken time and experience but Dalrymple has seen first-hand the productivity gains that can be achieved by feeding the rumen as a means of feeding the animal.
Although feed pad systems are uncommon in New Zealand, and sometimes unwelcome in an agricultural industry that capitalises on its pasture-based farming, it appears there is a place for them especially as sheep and beef farms become restricted to colder, steeper, and even drier climates.
There is also a lot to be learned from the process of sourcing and feeding a balanced ruminant diet, paying close attention to the composition of the major nutrients in the feed, and obtaining frequent feedback from the animals.
It could even spark greater use of high-starch supplements in pasture-based systems, an opportunity Dalrymple predicts farmers may use in the near future to improve livestock productivity.
- Alice Allsop
