Can Tho reduces pollution using circular livestock production

Ruminants such as buffalo, deer, cattle, and goats are considered “machines” capable of converting agricultural by-products into high-quality meat and milk.

Le Van Quang, representative of the Can Tho Sub-Department of Livestock Production and Animal Health, said, “Just by meeting a minimum roughage requirement of 2% of the ruminant’s body weight, the livestock and veterinary sector can utilize 872 tons of by-products from the crop sector, including rice straw, corn stalks, sugarcane tops, sweet potato vines, jackfruit leaves, and many more.”

These figures demonstrate the significant potential of agricultural by-products in ruminant livestock farming. Herd development for this category of livestock can contribute to reducing environmental pollution and enhancing disease prevention efforts.

Quang emphasized the importance of developing a circular economy in ruminant livestock farming as it helps farmers reduce input costs and turn waste into fertilizer. This approach also creates additional income sources from earthworm farming and by-products such as ensiled corn stalks, urea-treated straw, and composted manure as fertilizer. A circular system for beef and dairy cattle farming can enhance economic efficiency and expand the value chain by improving meat quality and milk yield.

By fully utilizing the abundant resources from agricultural by-products, numerous research studies and technological improvements have been recently implemented in practical ruminant livestock farming models following a circular approach.

Analysis from M.Sc. Nguyen Tien Si of Bac Lieu University shows that the method of processing agricultural by-products has been applied and proven to be effective in the context of increasing climate change and pollution.

In Can Tho city's ruminant livestock structure, cattle account for over 80%, with a total herd of more than 62,800 heads. Therefore, using available agricultural by-products as livestock feed is both practical and sustainable.

Rice straw, the most common agricultural by-product in the Mekong Delta, can be used immediately by cattle after harvest while still green, or dried for storage. It can also be ensiled with 4% urea or lime to break chemical bonds and facilitate digestion. Although this method has been widely introduced in agricultural extension programs, not many farmers choose to apply it.

Water hyacinth is a prime example as it grows abundantly in rivers, canals, and flooded areas of the Mekong Delta. Experts carried out a study in 2010 on ensiled water hyacinth residues as a supplement in beef cattle feed contents. As for the advantage of this solution, ensiled water hyacinth emits a pleasant aroma, which increases cattle's appetite. Replacing rice straw with 15 - 30% water hyacinth silage improves protein accumulation and weight gain in cattle.

Another notable by-product is jackfruit leaves. Each year, jackfruit orchards are pruned 2 - 3 times. M.Sc. Nguyen Tien Si sees the fresh jackfruit leaves after pruning as a potential feed source for cattle.

An experiment was conducted using ensiled jackfruit leaves to replace elephant grass completely. The results showed that this solution reduced methane emissions by 38.7% and CO₂ emissions by 41.6% without affecting livestock digestion.

Many farmers in Can Tho city now proactively apply green circular models in dairy farms. The design for those farms follow a closed-loop system from soil preparation, grass cultivation, and cattle care to waste treatment, thus forming a green circular cycle.

In particular, many dairy farms have invested in biogas waste treatment systems. Methane gas is collected and used as fuel to dry stored grass, heat water, and support farm operations. Treated waste becomes organic fertilizer for pastures and cornfields, thereby improving soil quality and reducing chemical fertilizer costs.

The need to change livestock farming practices calls for a synchronous combination between the State, businesses, and people. The State plays a role in providing guidance and supporting policies in terms of capital, science and technology, as well as planning concentrated livestock farming areas. Businesses participate in product underwriting, supply of breeds, feed, and technology transfer. Livestock households must change their mindset towards technology application, more professional and safer farming methods.

Biosecurity in livestock production still faces many limitations in the Mekong Delta in general and Can Tho city in particular. The characteristics of small-scale operation and traditional farming habits cause households to not pay attention to proactive disease prevention measures. Meanwhile, diseases in livestock and poultry spread rapidly, causing great damage and are difficult to control in the current context.