Utilizing Cover Crops as a Forage Resource for Heifers
August 3, 2021
The popularity of cover crops has grown significantly over the past few years. The benefits cover crops provide to improve soil health are well documented. Additionally, cover crops can benefit dairy producers as a forage source for young stock by saving higher quality forages for lactating cows. To optimize the use of cover crops, dairy producers should consider grazing, harvesting, and feeding techniques.
Though grazing has benefits, it may not fit every system. Most row crop fields are not fenced, meaning temporary fencing can be used on the interior of field. However, cattle temperament must be considered if using temporary fencing for the field’s perimeter. Heifers can cause soil compaction and muddy areas during the wet times of the year. Producers should take into account the soil conditions of the field. Allowing heifers to graze cover crops in the late fall or early spring could lengthen the grazing season and help farmers save on additional hay costs.
Harvesting cover crops at the optimal time can be challenging due to weather and the potential overlap with hay harvest. The optimal harvesting window depends on the chosen cover crop. For example, rye has a narrow harvest window for high quality forage. Triticale has a longer harvest window with better feed quality.
Harvested cover crops should be treated as any other forage on the farm. A forage analysis should be completed to help determine the feed value. Forages harvested at early maturity (boot stage) tend to be higher quality than those harvested at a later stage (dough stage). However, harvesting the cover crops too early may lead to low forage yields. Monitoring the stage at harvesting and completing forage analyses can determine which group of heifers are best suited for that crop.
Feeding the cover crop based on forage quality can impact growth rates of the heifers. To reach an age at first calving goal of 22 to 24 months, heifers should be approximately 55% of their mature body weight and 90% of their structural growth by 13 to 15 months. To help reach growth goals, higher quality cover crop forages should be fed to pre-bred heifers. Cover crops harvested at a later stage should be reserved for bred heifers to avoid over conditioning. Limit or avoid the feeding of cover crops to dry cows due to the risk of high potassium. Producers should work closely with their nutritionist to optimize the use of cover crop forages in the heifer diets.