In making the most of maturing green feed it is valuable to know what’s happening within the pasture and its impact on grazing. As lush green feed matures the plants begin to put energy into hardening and growing the stem. The natural purpose for this is to get the seeds as high in the air as possible so, at the right time, they can be effectively dispersed in the wind. This process generally begins in mid-spring and although it’s great for pasture reproduction, it is not ideal for grazing operations, as it can see the energy, protein and digestibility of the pasture decline rapidly.
Dr Paul Meggison, local producer and Chief Nutritionist at AusFarm Nutrition Products, discusses how to effectively use maturing green feed as an economic protein source and what to consider when getting the most out of mature green feed. Dr Meggison presents a strong case for grain assisted green feed grazing when paired with a built-for-purpose mineral supplement like StockMins-Lamb Finisher.
Key Points:
- Maturing feed declines in digestibility, meaning livestock consume and utilise less of it
- As feed matures the energy content of the feed reduces. Supplementing grain can boost energy
- Balancing dietary protein and energy is important for achieving rapid liveweight gain
- Minerals, vitamins and trace elements are important to support production on maturing green feed
- StockMins-Lamb Finisher is a built-for-purpose supplement that provides all the ingredients to boost digestibility, support grain supplementation and elevate rumen function of lambs grazing maturing green feed
Consideration 1: Poor Digestibility
In hardening of the stem, the digestibility of maturing feed decreases significantly. If a feed is difficult to digest it will sit in the rumen for longer than easily digestible feed, thereby, due to gut fill, reduce the daily consumption of feed. The decline in digestibility as a pasture matures arguably has the largest impact on the productive capacity of green feed. A 40kg lamb can consume around 1.6kg of lush green feed per day, however, the same 40kg lamb can only consume around 1.1kg of maturing green feed (see pasture chart – digestibility around 70%).
Solution: Dr Meggison recommends boosting the digestibility of maturing green feed by offering low level urea supplementation. “Even at small levels in the diet, urea is very effective at increasing the digestibility of maturing feeds. Effective urea supplementation can see an animal increase feed consumption by up to 30%, and the more feed an animal can eat the better it’ll perform.”
StockMins-Lamb Finisher contains 2.5% urea to assist in boosting mature green feed digestibility and consumption.
Consideration 2: Low Energy
As green feed matures and becomes less digestible, it also declines in energy. For example, a lush green pasture with energy of 10.8MJ ME/kg DM would likely have an energy content of around 9.9MJ ME/kg DM during the late vegetative stage and even lower during early flowering (see pasture chart). This can have a direct and significant effect on livestock growth rates, where liveweight gain achieved in winter is no longer supported on late vegetative or early flowering pastures.
Solution: Dr Meggison recommends boosting the energy level of the diet by feeding high energy grain. “Supplementing the diet with energy in the form of barley at 400 to 500g/hd/day can keep lambs moving forward and get the most out of the available green feed. This year, the issue will likely be more pronounced in many southern areas due to the prevailing dry conditions, shortage of fodder and early pasture maturity.”
StockMins-Lamb Finisher contains effective buffers to reduce the risk of acidosis when feeding medium level grain.
Consideration 3: Declining Protein
Although in the early stages of maturity green feed can be quite high in protein, declines as the feed goes to head and dries off. Successful green feed grazing in spring involves utilising the protein effectively while it’s available and balancing protein and energy through grain supplementation.
Solution: Dr Meggison discusses the importance of balancing energy and protein by effective supplementation. “Grain supplementation is about getting the balance between energy and protein right. During the early stages of maturity, protein in green feed is generally sufficient to support 500g/hd/day of barley, however, as pasture reaches mid flowering, a protein source, like lupins, may be added to balance the diet. This may also serve as a sign to consider more efficient production elsewhere, like on lucerne, a summer crop or in a feedlot.”
Consideration 4: Low Mineral Content
A combination of poor digestibility and low mineral content of maturing green feed can hinder livestock performance and reduce liveweight gain.
Solution: Dr Meggison suggests feeding StockMins-Lamb Finisher, free-access in troughs in the paddock, as a built-for-purpose supplement that effectively delivers essential minerals, vitamins and trace elements, while providing buffers, Bovatec® and urea to support grain supplementation, improved rumen function and pasture digestibility. “Like in human nutrition, mineral supplements are built for specific purposes. StockMins-Lamb Finisher is designed to support rapidly growing lambs grazing mature green feed or lucerne where grain supplementation is required to achieve rapid liveweight gain.”
For more information about StockMins-Lamb Finisher, or assistance in growing your livestock on mature green feed, contact AusFarm Nutrition Products today on 0412 048 055.
