WYTHEVILLE, VA — Virginia Extension recently held a weeklong series of dairy conferences, in Wytheville as well as Amelia Court House, Brandy Station, Dayton and Rocky Mount. The featured speaker came from the USDA’s Dairy Forage Research Center in Wisconsin.
Dr. Wayne Coblentz is a research dairy scientist and agronomist. In his studies, he measures how the nutritional characteristics of forages change due to variations in agronomic inputs, the application of animal wastes, grazing, climate, and post-harvest management. At the conferences, he spoke about the key components of making baled silage.
Other speakers at the events included Virginia Tech’s Dr. Bob James and Dr. Gonzalo Ferreira. Other topics discussed included the comparative risks and benefits of feeding calves milk versus milk replacers as well as ways to manage, measure, and monitor dairy calves and heifers.
According to Dave Winston, extension dairy scientist at Virginia Tech, calf and heifer comfort, “begins with dry cows,” with the goal of ensuring calving goes well.
An ideal environment for calving is a gently sloped grass pasture with lots of sunshine. Another good environment is a box bedded with straw.
Once you have a calf to manage, you want to provide housing that is clean, dry, well ventilated and draft-free.
Keeping stress low in calves is an important aspect of quality calf management. Temperature can be a stress on calves, so when the temperature drops, consider using calf jackets or adding extra bedding.
Other stressors on calves include management activities, transportation and social changes. When performing management activities such as dehorning or ear tagging, Winston recommends undertaking just one activity per day. “Don’t be additive,” he said.
Developing protocols is a way to increase the consistency and repeatability of practices in calf and heifer management, Winston said. “The larger a dairy is and the more people that work there, the more important protocols are.”
Winston suggested also developing protocols for, dealing with dry cows, newborn calves (including colostrums management), vaccination and sick cows.
Just creating and communicating protocols is not sufficient to ensure consistent management, though, Winston said. You also have to follow up to make sure the protocols are being followed.
Many dairies have opportunities to improve heifer management. While dairies do often measure age, heat cycling, breeding, and vaccination of heifers, he also encouraged operators to see the importance of growth monitoring of heifers.
“I would say that growth is to heifers as milk is to cows,” he said.
A benefit of growth measurement is that if you have growth data on a group of heifers you can evaluate your nutrition program.
If you have a scale or are installing one, Winston recommends weighing heifers every month, or at least every two months. It could help you get better heifers and find ways to save money in your operation.
Dr. Coblentz began his talk on making baled silage by stating that the principles of silage are the same regardless of the type you’re making. Foremost of those principles is the quality of the resulting silage depends on starting with “high-quality forage.”
So why choose baled silage over dry hay? The advantages include less risk of spontaneous heating, the ability to store outside, less risk of rain damage due to lower wilt time, less leaf loss in legumes, and better nutritional characteristics.
When making silage, you want to remove oxygen as quickly as possible, to establish conditions that encourage the proliferation of desirable microorganisms. You want to encourage lactic acid-producing bacteria, encouraging lactic acid fermentation. You want to avoid clostridial fermentation, which produces butyric acid and higher levels of ammonia nitrogen, which in the worst cases will produce a feed that cattle won’t eat.
Baled silage is different than precision chopped silage in that less total fermentation typically occurs in baled silage. Consequently, the resulting pH of baled silage is not as low as that typically found in precision chopped silage.
Silage quality also differs based on plant factors, which vary by species. Those factors include the amount of water-soluble carbohydrates (the substrate necessary for fermentation) available and the plant’s buffering capacity (the plant’s inherent resistance to pH change).
Corn and forage sorghum are very high in water-soluble carbohydrates (WSCs), while perennial warm season grasses are low in WSCs. The availability of WSCs is also affected by N fertilization rates and rain damage. Damage from rain is less when the forage has just been mowed, while leaching of sugars is higher when rain comes on drier forage.
When it comes to buffering capacity, corn and forage sorghum again “top the list,” Dr. Coblentz said, while legumes have higher buffering capacity.
Coblentz recommends making baled silage at 45 – 55 percent moisture — 42 percent, silage won’t produce much lactic acid.
Higher moisture levels not only present the safety risk of handling heavier bales, there’s also a higher risk of clostridial fermentation.
Coblentz noted that there are risks to making baled silage when the forage is contaminated, such as with dirt or manure. That includes forage which has seen a recent application of livestock manure. In such cases, the chance for clostridial fermentation is elevated.
When making baled silage, wrap the forage as quickly as possible once you reach your desired moisture level. Use four to six layers of plastic. When using an in-line wrapper, aim to produce consistent bales, so the top line of the wrapped tube is level.
For further questions about making baled silage, check with your local extension agent.