Researchers tested whether soybean meal could replace expensive milk-based proteins in feed for young donkeys. They fed 42 baby donkeys different types of protein supplements from age 10 days to 130 days and tracked their growth, gut bacteria, and blood chemicals. Donkeys fed soybean meal grew faster, gained weight more efficiently, and had healthier gut bacteria compared to those fed milk-based proteins. The soybean meal also boosted growth hormones and reduced stress hormones in the donkeys’ blood. This discovery could help farmers raise healthier donkeys while spending less money on expensive milk-based feed ingredients.

The Quick Take

  • What they studied: Whether soybean meal could work as well as or better than milk-based proteins in feed for baby donkeys, and how each type of protein affected the donkeys’ growth, gut health, and blood chemistry.
  • Who participated: 42 healthy baby Dezhou donkeys, all starting at 10 days old. The donkeys were divided into three equal groups of 14, each receiving different protein sources in their supplemental feed for 120 days.
  • Key finding: Baby donkeys fed soybean meal grew significantly faster and more efficiently than those fed milk-based proteins. They also had better gut bacteria, higher growth hormones, and lower stress hormones in their blood.
  • What it means for you: If you raise donkeys, soybean meal may be a cheaper and more effective alternative to expensive milk-based proteins. However, this research was done only on donkeys, so results may not apply to other animals. Talk to a veterinarian before changing your donkey’s diet.

The Research Details

Scientists divided 42 baby donkeys into three groups when they were 10 days old. One group received soybean meal as their main protein source, another received milk-based proteins (like milk powder and whey), and the third group received a mix of both. All groups were fed the same way otherwise, and the study lasted 120 days until the donkeys were 130 days old.

The researchers measured how much the donkeys weighed, how much they ate, and how efficiently they converted food into body weight. They also collected samples from the donkeys’ intestines to study the bacteria living there, and took blood samples to measure hormones and other chemicals that affect growth.

This type of study is called a randomized controlled trial, which is considered one of the strongest ways to test whether something actually works. By randomly assigning donkeys to groups and keeping everything else the same, scientists can be more confident that any differences they see are caused by the protein source, not other factors.

Understanding how different protein sources affect donkey growth is important because protein is expensive and crucial for young animals. By finding cheaper alternatives that work just as well or better, farmers can save money while raising healthier animals. This study also shows how food choices affect the invisible bacteria in the gut, which play a big role in health and growth.

This study has several strengths: it used a randomized controlled design with three groups, included a decent sample size of 42 animals, measured multiple outcomes (growth, gut bacteria, blood chemistry), and lasted long enough to see real effects. However, the study only tested one breed of donkey, so results might differ for other donkey breeds or animals. The research was published in a peer-reviewed journal, meaning other experts reviewed it before publication.

What the Results Show

Donkeys fed soybean meal grew significantly faster than the other two groups. By day 130, they weighed more and gained more weight each day on average. This difference was very clear and unlikely to be due to chance (P < 0.001, which means there’s less than a 1 in 1,000 chance this happened randomly).

The soybean meal group also used their food more efficiently. They needed less feed to gain the same amount of weight compared to the milk-protein group. This is important because it means farmers would spend less money on feed while getting bigger, healthier donkeys.

Blood tests showed that donkeys in the soybean meal group had higher levels of growth-promoting hormones and vitamins. Their thyroxine (a hormone that controls metabolism), growth hormone, and growth factor levels were all significantly higher. They also had higher vitamin B6, which is important for many body functions. Interestingly, their stress hormone (cortisol) was significantly lower, suggesting they were healthier and less stressed.

The gut bacteria analysis revealed major differences between groups. Donkeys fed soybean meal developed different and apparently healthier communities of bacteria in their intestines. Several types of beneficial bacteria became much more common in the soybean meal group, including bacteria that are known to support good health and digestion.

Chemical analysis of the blood identified 15 different metabolites (chemical products made by the body) that differed between groups. These metabolites were related to important processes like vitamin B6 metabolism, amino acid processing, and the production of serotonin (a chemical that affects mood and digestion). The beneficial bacteria that thrived in the soybean meal group showed strong positive connections with these helpful metabolites and with the donkeys’ growth rates.

Previous research suggested that milk-based proteins were superior for young animals because they’re easy to digest and have all the right amino acids. This study challenges that assumption by showing that soybean meal can actually outperform milk proteins in some situations. The findings align with recent research showing that plant-based proteins can support healthy gut bacteria development, which may explain why soybean meal performed so well. However, most previous studies focused on other animals, so this is one of the first clear demonstrations in donkeys.

This study only tested one breed of donkey (Dezhou), so results might be different for other donkey breeds or sizes. The study lasted 120 days, which is good for seeing growth effects but might not show long-term health impacts. The research was conducted in a controlled farm setting, so real-world results might differ depending on climate, other feed ingredients, and management practices. Additionally, while the study shows correlation between gut bacteria and growth, it doesn’t prove that the bacteria directly cause the improved growth—other factors could be involved.

The Bottom Line

For donkey farmers: Soybean meal appears to be an effective and potentially superior alternative to milk-based proteins for feeding baby donkeys from 10 days to 130 days of age. It may improve growth rates and reduce feed costs. However, introduce any dietary changes gradually and monitor your donkeys’ health. Consult with a veterinarian or animal nutritionist before making major feed changes, as individual donkeys may respond differently. Confidence level: Moderate to High for donkeys; Lower for other animals.

This research is most relevant to donkey farmers and breeders looking to improve growth performance and reduce feed costs. It may also interest researchers studying gut health and animal nutrition. Pet donkey owners should consult a veterinarian before changing their animals’ diet. This research does not directly apply to horses, cattle, or other animals, though some principles might be similar.

Based on this study, you could expect to see noticeable differences in growth rate within 4-6 weeks of switching to soybean meal-based feed. More significant weight gains and improved feed efficiency would become apparent over 8-12 weeks. Changes in gut bacteria composition likely occur within 2-4 weeks, though the full benefits may take the entire 120-day period to fully develop.

Want to Apply This Research?

  • If managing donkeys, track weekly weight measurements and daily feed consumption amounts. Calculate feed conversion ratio (weight gained divided by feed consumed) every two weeks. Monitor for any digestive changes or health issues.
  • For donkey farmers: Gradually replace 25% of milk-based protein with soybean meal over one week, then increase to 50% over the next week, and finally transition to full soybean meal supplementation. Monitor donkey behavior, appetite, and digestion throughout the transition.
  • Establish a baseline of current growth rates and feed costs before making changes. After switching to soybean meal, track weight gain, feed efficiency, and overall health monthly. Keep records of any digestive issues, appetite changes, or health problems. Compare costs monthly to quantify savings. Take photos every 30 days to visually document growth improvements.

This research was conducted on baby donkeys and may not apply to other animal species or donkey breeds. The study was performed in a controlled research setting and results may vary based on individual animals, climate, management practices, and other feed ingredients. Before making any changes to your donkey’s diet, consult with a veterinarian or qualified animal nutritionist. This information is for educational purposes and should not replace professional veterinary advice. Individual donkeys may have different nutritional needs or sensitivities. Monitor your animals closely for any adverse reactions when introducing new feed ingredients.