Food and Feed from Plants

Corn grain is highly digestible for both humans and ruminants. What is the feed to food conversion ratio on an energy basis to produce beef meat from corn grain? What is the conversion ratio for chicken from corn grain?

The feed:food ratio for cereal-fed beef is 13:1, whereas for chicken it is 5:1

Briefly explain why ruminant animals (like beef cattle) generally have a lower total gross feed efficiency and larger caloric input-to-output ratios compared to monogastric animals (like poultry).

Ruminant have a lower total gross feed efficiency and larger caloric input-to-output ratios compared to monogastric animals because their multi-chambered stomachs are geared towards digesting high-cellulose foods such as grasses. This means that they are able to fulfill a special ecological niche, but break down food much slower and lose a lot of it to gasses as the microorganisms in their rumen work to break down cellulose in food. Monogastric animals do not have this extra step, and are able to more efficiently and directly break down foods, however they cannot break down cellulose rich food.

Name some of the common crops used in the diets of livestock raised for milk, beef

meat, and poultry meat production.

Soybeans, Corn, Barley, Wheat

For each of the following grain crops, what is the approximate percentage used for

animal feed in the USA? Wheat, barley, corn.

Wheat - 22%, Barley - 51%, Corn - 43%

Regarding the proposition that we attempt to solve the global food-supply crisis in the next 50 years by changing eating habits such that we eat less animal-based foods, what are some of the key issues?

Some key issues are:

• Ruminant animals often allow for turning byproducts into food directly thanks to their ability to digest cellulose

  • similarly, these animals also allow for turning land unsuitable for cultivation into land for food production, especially in areas such as Africa, where food security is already an issue.

• Munch or mulch?

  • Leave crop residue to protect the soil and rejuvenate it for future years (mulch)

  • Feed it to animals for the food, labor, and manure (munch)

Based on the data models from Cassidy et al. (2013), the United States has a very low Calorie Delivery Fraction (< 20%) compared to countries like India or Sub-Saharan Africa. Explain the structural difference in crop allocation that drives this divergence.

The reason that the US has a very low calorie delivery fraction vs India or Sub-Saharan Africa is because much of our crop production that could be suitable for direct feed for humans goes towards animals or other industrial products. In countries such as india and SSA, livestock largely consumes food that is otherwise inedible to humans and converts it into food, meaning it is not competing with human food and thus not lowering the calorie delivery fraction.