Posted by Administrator on June 24 2009 15:19
Introduction
If someone could develop a green cow, it would make the life of a producer less stressful and more profitable. What do I mean by green cow, a cow that makes its own food instead of supplying the food necessary for growth and development? We know that will likely never happen, so in times of higher feed prices and lower cattle prices (an oxymoron), the decisions will get tougher, strategy will become a management practice and creativity will become a common word around the homestead. It’s inevitable that feed prices, such as corn, are not on the decline anytime soon. We know this to be true with the demand for corn due to the booming ethanol industry. We also know that profit margins in cow/calf production are narrow in part because feed costs typically represent up to 60% of all cost. With a short forage growing season (˜ 120 days) in the northern Great Lakes region, a constant challenge producers’ face is implementing methods to reduce winter feeding cost by extending the grazing season in the fall and winter. Producers must realize that what is termed “grazing season” is not limited to the period of time when forages are actively growing.
Well-managed pasture-based livestock operations can significantly enhance profitability by improving animal and pasture performance, increasing harvest efficiency, reducing stored feed cost, reducing the chance of weed problems and will result in a longer grazing season. Along with a well-managed summer pasture system, there are methods that can be used to extend, or lengthen, the grazing season in the fall. Carry-over of pastures not grazed, stockpiling forages and windrow (swath) grazing. Carry-over forages could classify as stockpiling forages because those pastures have not been grazed for a period of time and would be left for a later grazing date. For now, we will assume that carry-over forages fall under stockpiling forages.
Stockpiling Forages
Stockpiling is the process of growing the forage till frost and letting the animals harvest their own feed at a later date. Usually this later date is during the fall months and sometimes into early winter. Any forage specie (annual or perennial) can be stockpiled; however, some species are more suitable than others based on palatability and forage quality. There are two main reasons why stockpiling forages should be considered to extend the grazing season: 1) it can replace mechanically harvested stored forage and reduce your feeding cost, and 2) it can improve pasture utilization the subsequent season by staggering spring “flush” and early summer growth.
Disadvantages
As with anything else, there are disadvantages to stockpiling forages for fall grazing. Forage quality, quantity, and utilization can be affected by fall moisture, fall nitrogen availability, and winter weather conditions. While nitrogen applications, followed by timely rainfall, will improve the quality and quantity of the stockpiled forage, quality and availability will depend on snow cover and temperature conditions throughout winter. Research out of Wisconsin suggests that cattle can graze through 8” of snow; however, utilization may suffer with excessive amounts of snow or ice. The longer stockpiled forage is left standing; the lower the forage quality and quantity. Energy levels of stockpiled forages deteriorate more rapidly than protein levels.
Implementing a stockpiled fall grazing system to extend your grazing season starts early. Early summer is a good starting point to initiate the stockpiling process based on
- availability of pastures or hayfields for deferred use
- nutritional needs of cattle that will graze the stockpiled forage
- average first frost date
- intended grazing start date.
Some perennial grasses work better than others (tall fescue and orchardgrass) with regards to production, palatability, and quality. Grass-legume varieties work well in a stockpiled forage system, but these varieties should be grazed in early fall because yield and quality of legumes can deteriorate rapidly after first frost. If multiple pastures are going to be used with some pastures consisting of legumes, graze those pastures with the highest legume content first, followed by pastures with higher grass content later in the fall. Rotation of cattle within a stockpiled pasture will increase carrying capacity of that pasture and improve forage utilization. It is recommended to allocate enough forage to provide at most one-weeks worth of feed.
Windrow Grazing
Windrow, or swath, grazing has been extensively used in the northern U.S. and Canada. Windrow grazing is the process of cutting hay, leaving it in windrows and allowing livestock to graze these windrows later in the fall. This process of grazing has been shown to extend the grazing season by as much as 45 days with minimal effects on cattle performance or consumption when grazing in most severe weather conditions. Canada has demonstrated that body conditions of cattle have not been affected when grazing windrows in early winter and Nebraska reported from a two year study that weaned steer calves either gained weight or showed no difference in gains when grazing windrows vs. fed stored hay. Windrow grazing is being done extensively with annual crops such as barley, oats, and triticale, as well as some perennial crops. By letting cattle harvest the forage instead of mechanical harvesting, cost of processing and feeding hay can be reduced by as much as 60% to 75%. Not only will labor requirements for haying and feeding be reduced, but windrow grazing eliminates bailing, hauling, stacking, and feeding. Other advantages include weather becoming less of a factor at haying if windrows are left for grazing vs. baled for stored forage, decrease in manure handling in dry lots and a more evenly distribution of manure in a windrow grazing system.
However, there is risk associated with a grazing system that extends into the fall and winter months, but these risks are often times more perceived than actual. Crusting of snow or ice on windrows can cause sore noses on cattle trying to push the ice or snow away and can negatively impact consumption. Wind can blow windrows before they are grazed, especially if there is no layer of snow covering these windrows. On pastures or hay fields where cattle are grazing windrows, availability of fencing, shelter and heated water (particularly later in the fall) may be limited.
Another big concern with allowing forages to lay in windrows over a period of time is nutrient depletion. Several studies in the northern U.S. and Canada have addressed these concerns with respect to nutrient depletion. Nutrient values of alfalfa/grass bales cut in August (CP - 14.5%, TDN – 59.6%) were compared to swathed alfalfa/grass windrows in October (CP – 17.6%, TDN – 55.2%) in southwestern Colorado (LaShell et al., 2002). Volesky et al., 2002 also reported that CP values for wet meadow/cool season perennial grass/legume hay was similar and TDN was greater compared to forage left as windrows in the fall. While it seems that the concentration of nutrients in forages cut for windrows do not significantly decrease over time, these studies were conducted in climates of low moisture and low humidity. So why couldn’t windrow grazing work in Minnesota? Minnesota can get as much as 35 inches/year, and high levels of moisture (rain, snow or humidity) can dilute the concentrations of nutrients in forages, particularly energy, over a period of time.
To address that question, studies were conducted at the North Central Research & Outreach Center in northern MN to compare forage varieties (annuals and cool season perennials) for nutrient values from baled hay and swathed windrows in the fall of 2005 and 2006. Forage varieties compared in 2005 included alfalfa, tall fescue (analyzed as stockpiled forage) and Italian ryegrass; and forage varieties compared in 2006 included Italian ryegrass, Italian ryegrass/oats, and Italian ryegrass/triticale (Table 1). In 2005, forage CP increased as TDN decreased over time for windrows which supports data from southwestern Colorado and Nebraska (Lashell et al., 2002; Volesky et al., 2002). This CP increase and TDN decrease over time is likely due to leaching of carbohydrates that will cause an increase in the concentration of CP. However, 2006 data showed both CP and TDN values decreased over time in windrows vs. baled hay. The authors would like to note that the largest percentage loss of CP (2.6%, 2006 data) and TDN (9.5%, 2005 data) was not a significant loss in these forage varieties. Thus nutrient concentrations of those forages were high enough to meet minimum maintenance (and possibly gain) requirements for spring calving cows. Thus, two years worth of forage quality data in northern Minnesota demonstrates that moisture (rainfall or snow) does not significantly alter forage quality of the forage varieties tested.
For a windrow grazing system to be successful, good management is necessary so that cattle stay healthy and maintain adequate body condition. Fitting the right type of cattle based on their nutrient requirements to the nutrients offered from the forages in windrows is critical. The steps below will walk you through setting up and managing a successful fall windrow grazing system.
Selecting a Field
Field selection can ultimately have an effect on length of the grazing season and labor requirements. When selecting a field to be used for windrow grazing, make sure a water system (heated) is available everyday. The field or pasture must be easily accessible to monitor animal conditions and if supplemental feed has to be provided. The field must have protection from the wind; whether the windbreak is portable or in the form of trees.
Crop Selection
Annual crops. Winter triticale, barley, and oats are the most common crops used in Canada and the northern U.S. Grain varieties that are high yielding tend to produce higher forage yields. By selecting forage types that are late maturing, forage quality at time of swathing can be enhanced, as well as providing enough quality while in windrows over time. Research at NCROC in northern Minnesota has indicated that oats and winter triticale, used with Italian ryegrass, are crops that can maintain its quality in windrows through December. Oats is a crop that is easy to establish producing high yields (1758 lbs dry matter/acre NCROC study); however, winter triticale is slow to establish, but used with Italian ryegrass produces sufficient yields for grazing (1243 lbs dry matter/acre NCROC study). These annual crops should be seeded so that when crops are harvested before the first frost, these crops are in the early heading to soft dough stage. These crops should be seeded in late July to early August.
Perennial crops
Information on perennial crops used for swath grazing is limited; however, forage yield and quality of Italian ryegrass and alfalfa/tall fescue have been tested at the NCROC suggesting that these three perennial crops would be suitable for windrow grazing in northern Minnesota. Perennial crops to be used for windrow grazing should be seeded in early spring, unless pastures have already been established. Just like annual crops, perennial crops are harvested just prior to first frost (typically around the end of September/early October). Fields or pastures seeded or established with perennial crops can be grazed or harvested for hay in early summer; however, it is recommended that fields be ignored starting in mid July.
Fertilizing
Normal fertilizer application rates for annual grain and perennial crops are adequate for swath grazing. Knowing what amounts of fertilizer is needed is best known by taking a soil sample. However, there is caution if a history of high nitrogen fertilization or repeated manure applications on the field to be used for swathing has occurred in the last several years, nitrate accumulation can be a concern if grazed by livestock.
Swathing
How long forages left as windrows can sustain their quality depends on management of the windrows at time of swathing. For most crops, two windrows should be raked together within two days after cutting, unless yields are less than 1 ½ tons/acre, then three windrows should be raked together. Windrows raked together, while still wet, will build a tighter, more compact windrow that is less susceptible to wind damage. Windrows should be no more than four feet wide. High, dense windrows are preferred and should lie on top of the stubble. The reason for high dense windrows is to keep the majority of forage off of the ground to prevent spoiling or molding. Forages, such as Italian ryegrass can have yields of two plus tons/acre of dry matter. Because Italian ryegrass is high in water content (low percentage of dry matter), if windrows are too large, the weight and density of the forage will not allow much air flow through the windrows. This increases the chance of molding or decaying on the bottom layers of those windrows and animal intake may decline. It is recommended that single rows of windrows be left for grazing if the forage has a high water content, such as Italian ryegrass. Other forages such as alfalfa and tall fescue have a higher dry matter concentration so the potential for molding or decaying is less.
Stocking Your Pasture
It is important to know what the quality of forages to be used are and the type of cattle (stage of production) grazing the windrows. Nutrients such as CP, TDN, fiber content, and mineral levels must be sufficient enough or exceed nutrient requirements for maintenance of cattle grazing windrows in good body condition. Within a given pasture, multiple random samples should be taken from across the field and the samples must be representative of the crop being grazed. As seen with studies described earlier, forage quality will decline in windrowed forages or crops over time. Energy and digestibility will be affected the most. Forage quality of windrowed forages used in the NCROC study slightly declined over time, but exceeded nutrient requirements for spring calving pregnant dry cows. In fact, average daily gains of those spring calving pregnant dry cows were 2.0 and 2.1 when grazing windrows on the two different pasture types. However, if replacement heifers or fall calving lactating cows will be used in the windrow grazing system, energy supplements may be needed because nutrient requirements for those animals are much higher.
Grazing Management
One of the most important, and challenging, factors to grazing cattle on windrows is controlling the amount of swath that is accessible to the cattle. If cattle are allowed to graze windrows in a continuous type grazing system, cattle will only graze portions of the windrow which can lead to significant loss of available forages within the field or pasture.
Electric fencing and forage loss
A well managed windrow grazing system can be equal to or higher in feed efficiency than winter fed stored forage. Feeding losses with stored feeds are often in the 5% to 20% range and harvesting and storage losses of hay and silage can be as high as 30%. Electric fencing is one of the easiest and cheapest ways to regulate the quantity of forage in windrows available for consumption to cattle. Cattle left in one area too long will tend to use the windrows as bedding and reduce the amount of forage available for consumption. By allowing cattle to graze small confined areas you can significantly reduce the amount of forage loss. You are basically implementing a rotational grazing system. This prevents cattle from trampling, defecating or bedding over a large area of the field. Electric fencing should be set up so that cattle graze down the length or face of the windrows with an electric fence wire running across the windrows instead of grazing the full length of the windrows
Summary
Swath grazing is a viable option for many producers. This practice offers producers the potential to reduce feed and labor cost while utilizing what most producers can produce at an extremely lost cost, forages. As with any new management practice, it requires thinking and planning ahead. Factors that need to be considered early in the planning season is field location and characteristics, type of animal and animal condition, types of crops, water availability, shelter, fencing and manure management. Most importantly, producers must assess the economic feasibility for your own program before implementing a fall windrow grazing system.