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Feed management is often the elephant in the room when considering a dairy farm’s costs of operation. And yet, what if the returns from these costs could be improved by addressing some of the most obvious but overlooked solutions?
It is essential to reduce variation when dealing with what represents – on average – 45% of the cost of operating and is a major source of stress for both the animals and employees. The most frequent sources of variation in dairy feeds – particularly in silages – occur at the bunker silo, the feed mixer and in the cow’s digestive tract.
The bunker silo
Silage face management, feedout rates, sealing quality and packing density are all areas of bunker management that can, if done properly, minimize feed spoilage and maximize your dollar. The goal is therefore to reduce oxygen infiltration, both during packing and at feedout, to avoid spoilage.
When thinking of building new silos, think about selecting proper flooring and size. Smooth flooring, preferably made of concrete or asphalt, is crucial to avoid feed contamination and the buildup of rocks that cause equipment wear and tear or find their way into the cows’ ration. A flooring slope of 2% to 5% also allows for adequate drainage – away from the site rather than toward the silo – to maintain cleanliness and reduce contamination.
Next, proper silo dimensions are essential for safety, cost and feed management. The maximum height should be safely accessible by defacing equipment, and the minimum bunker width should be roughly the width of two packing trailers. To limit oxygen infiltration, aim for the removal of 30 centimetres of silage. Adhering to these dimensions will help maintain a sufficient feedout rate.
When filling the silo, great attention needs to be put on packing and covering to avoid oxygen infiltration through the top and sides of the silage pile. Plastic and oxygen-limiting barrier films are a great way to cover the silage, along with tires or sandbags closely laid side by side to hold the barrier in place. When feeding out, beyond ensuring that an adequate amount of feed is removed daily, there should be no leftovers remaining at the bottom of the silo, as they will be quick to spoil. Depending on the amount of spoiled feed, intake and feed digestibility may decrease by 13% and 17%, respectively.
A 30% to 40% decrease in loss of dry matter due to mismanaged silos can be prevented by following these simple steps.
The TMR mixer
After collecting silages from bunker silos, it is essential to properly prepare the total mixed ration (TMR) with the appropriate particle length of ingredients. Cows require fibre and forage to stimulate chewing activity and saliva production, and both are necessary to maintain proper ruminal pH and a healthy rumen. If the TMR particles are too long, cows will be able to sort through it, leaving out coarser items and altering ruminal degradation. It is important to prevent sorting, as this results in an unbalanced intake, increasing the risk of digestive disorders, like acidosis, which ultimately affect productive performance and farm profitability. Although different stages of production have different nutritional requirements, a good TMR should always have uniform chemical and physical dietary characteristics.
Monitoring the TMR preparation process helps identify factors that may affect TMR characteristics and the ease of the feeding process. The best way to ensure your cows are getting the most out of their diet is to visually assess the feedbunk throughout the day. Observe and ask yourself if a good balance of all the TMR components is still available or if sorting has occurred.
Ultimately, physical characteristics of the ration are crucial to increase the cow’s dry matter intake (DMI) and support its energetic needs to support the desired level of milk production. When forage particles are too long, they create additional distention. This reduces the cow’s intake because signals from tension receptors throughout the gastrointestinal tract are generated and transmitted to the brain’s feeding centres. Ensuring cows consume a balanced diet is key to rumen health and milk production.
The cow’s digestive tract
Once the cow consumes her diet, the rumen is where the magic starts. The cow ferments the ration’s organic matter she ate to produce volatile fatty acids (VFA) and other substrates necessary to support milk production. Fibre is one of the key nutritional components of a dairy cow’s diet – along with starch and lipids – that influence ruminal fermentation. It is both the fibre’s chemical composition and particle length (known as the physically effective neutral detergent fibre or peNDF) that contribute to rumination, salivation and the formation of the rumen mat.
The rumen microbiome is composed of bacteria, fungi and protozoa whose synergistic functions allow them to properly ferment, digest and degrade ingredients. However, when diet characteristics change, they also impact the microbial community’s ability to colonize and degrade fibre, resulting in decreased fibre digestibility.
Beyond the rumen, the digesta it makes proceeds to the small intestine where most of the remaining nutrients (protein, fats, vitamins and minerals) will be absorbed and used by the cow. These nutrients support the animal’s metabolic processes needed for milk production, immunity and reproduction.
Conclusion
Ultimately, the difference between what is left in the manure and what was initially fed in the TMR is one of the ways to determine how much of the ration the cow digested and absorbed. This can be done through manure observation and screening, but for thorough evaluations, chemical analyses may be required. To increase profit generated from investments in feeds, it is essential feed is properly stored and preserved so cows can eat and digest the ration they receive as efficiently as possible.
References omitted but are available upon request by sending an email to the editor.
Things to consider when evaluating TMR preparation:
- Order of ingredient loading
- Scale balancing
- Mixing speed and times
- Distribution of the ration
- Feeding and pushing frequency
