Feed is a critical factor in ruminant animal production, directly influencing growth, health, reproduction, and productivity. In Kenya, where ruminant farming is a major livelihood activity, understanding the nature of ruminant feeds and how to formulate balanced diets is essential for extension professionals advising farmers. This chapter explores the types of feeds suitable for ruminants and the principles of feed formulation tailored to local resources and production goals.

2.1 Ruminant feeds

Ruminant feeds vary widely in composition and nutritional value, reflecting the diverse agro-ecological zones across Kenya. Extension professionals must guide farmers in selecting appropriate feed resources that optimise rumen function and animal performance. This topic defines the key terms used in ruminant feeding, explains why feed matters, and describes the types of feed: concentrates, forage and pastures. It also covers the nutritional components of feeds and the role of feed additives.

2.1.1 Definition of terms

Clear terminology allows extension officers, farmers and feed suppliers to talk about rations in the same way. Example: when a farmer asks for a "balanced ration" for dairy cows, the officer must know whether this means forage alone or forage plus concentrates and minerals.

• Ruminant: A cud-chewing animal with a four-compartment stomach (rumen, reticulum, omasum and abomasum), such as a cow, sheep or goat (the camel chews the cud but has three stomach compartments). Microbes in the rumen allow it to digest fibrous feeds.
• Feed: Any material eaten by an animal that supplies nutrients for maintenance, growth, reproduction, lactation or work.
• Forage: Plant material, fresh or conserved, that is high in fibre and eaten by livestock. It includes pasture, hay, silage, fodder crops and browse.
• Roughage: Bulky feed with more than about 18% crude fibre on a dry matter basis and low energy value, such as hay, straw and stover.
• Concentrate: A feed that is low in fibre and high in energy or protein, such as maize germ, dairy meal and cottonseed cake.
• Pasture: Land covered with grasses and legumes that animals graze directly.
• Browse: Leaves, twigs and pods of shrubs and trees eaten by animals, such as Calliandra and Leucaena.
• Ration: The total amount of feed given to an animal in 24 hours.
• Balanced ration: A ration that supplies all the nutrients in the right proportions for a given class of animal.
• Dry matter: The part of a feed that remains after all water has been removed. Nutrient values are compared on this basis because fresh feeds differ widely in water content.
• Feed additive: A substance added to feed in small amounts to improve feed use, animal health or performance, but which is not itself a main source of nutrients.

2.1.2 Importance of Ruminant feeds

Feed is the largest running cost in most ruminant enterprises, so the quality and type of feed decide whether the enterprise makes a profit. Example: a smallholder with two dairy cows who feeds only mature Napier grass will get low milk yields, while the same cows given good forage, a concentrate and minerals will yield more.

• Maintenance: A proportion of every ration keeps the animal alive, maintains body temperature and supports basic body functions before any production can occur.
• Growth: Calves, kids and lambs need protein, energy and minerals to build muscle and bone, and well-fed young stock reach breeding or market weight sooner.
• Milk production: Lactating cows and goats need extra energy, protein and minerals to produce milk, and underfeeding lowers yield and the milk's solids content.
• Reproduction: Adequate feeding supports regular heat cycles, conception and healthy calving. Poorly fed animals show delayed maturity, weak heat signs and low conception rates.
• Health and immunity: Balanced feeding supports the immune system and reduces metabolic disorders such as acidosis and milk fever.
• Rumen function: Correct feeds keep the rumen microbes active so that fibrous materials are turned into volatile fatty acids and microbial protein.
• Profitability: Because feed forms a large share of production costs, efficient use of home-grown forage and well-chosen supplements raises the margin per animal.

Nutritional components of ruminant feeds

The nutritional quality of feeds determines the productivity and health of ruminants. Extension officers must understand the key feed components to advise on balanced feeding.

• Crude protein: Vital for rumen microbial growth and tissue repair. Leguminous forages such as Desmodium and Calliandra are important protein sources on farms.
• Energy: Derived mainly from carbohydrates and fats, energy fuels all metabolic activities. Grains such as maize and sorghum provide readily fermentable carbohydrates.
• Fibre: Mainly cellulose and hemicellulose, fibre supports rumen function by stimulating chewing and saliva production, which buffers rumen pH. High-fibre feeds include Napier grass and Rhodes grass.
• Minerals: Macro minerals such as calcium and phosphorus support bone development and metabolic functions, while trace minerals such as zinc and selenium contribute to enzyme systems and immunity.
• Vitamins: Fat-soluble vitamins (A, D, E) and water-soluble vitamins (B-complex) regulate metabolism, reproduction and disease resistance. Deficiencies can lead to poor growth and reproductive failures.
• Water: Although not a feed, clean water in adequate amounts is essential for feed intake and milk production, since milk is mostly water.

2.1.3 Types of Ruminant feeds

Ruminant feeds are broadly classified by their origin and nutrient content, which helps farmers and extension officers formulate diets that meet the animals' requirements under different production systems. The three types covered here are concentrates, which are rich in energy or protein, forage, which supplies bulk and fibre, and pastures, which animals graze directly.

Feed additives

Feed additives improve feed utilisation, enhance animal health and increase productivity. They are used in small quantities, mixed evenly into concentrates or mineral mixes. Extension officers should advise that additives support a good ration but never replace good forage and adequate nutrients.

• Enzymes: Exogenous enzymes added to feed help break down complex carbohydrates, improving digestibility and feed conversion efficiency.
• Probiotics and yeast cultures: These additives stabilise rumen microbial populations, enhancing fibre digestion and reducing digestive disturbances such as acidosis.
• Ionophores: Ionophores modify rumen fermentation patterns to increase propionate production, improving feed efficiency and weight gain. They are used mainly in beef feedlots and must be used strictly as directed by the manufacturer and a veterinarian or animal nutritionist.
• Buffers: Substances such as sodium bicarbonate neutralise excess rumen acidity, particularly in high-concentrate diets, preventing metabolic disorders.
• Growth promoters: Hormones and other compounds can increase growth rates and feed efficiency but are regulated and less commonly used in smallholder systems. Withdrawal periods and legal limits must be respected to keep meat and milk safe.

2.1.3.1 Concentrates

Concentrates are feeds with a high content of energy or protein and a low fibre content. They are used to top up forage when forage alone cannot meet the needs of high-producing animals such as dairy cows in early lactation or beef animals being finished. Example: a farmer feeding Friesian cows on Napier grass may add dairy meal at milking time to meet the extra energy and protein needed for milk production.

Concentrates include:

• Energy concentrates: Cereal grains such as maize, sorghum and millet, and by-products such as maize germ, wheat bran, pollard, molasses and brewers' grains. They supply readily fermentable carbohydrates and have less than about 20% crude protein. By-products from agro-industries are cost-effective but need careful inclusion rates to avoid imbalances.
• Protein concentrates: Oilseed cakes and meals such as cottonseed cake, sunflower cake and soya bean meal, and also fish meal, which is used sparingly for ruminants. They contain roughly 20% or more crude protein and are used to correct protein shortages.
• Commercial compounded feeds: Dairy meal, calf pellets and beef finisher feeds are blended by feed manufacturers to a defined nutrient level and usually include minerals and sometimes additives.
• Mineral and vitamin supplements: Mineral licks, salt and vitamin premixes prevent deficiencies that impair growth, reproduction and immunity. Calcium, phosphorus and salt are the minerals most often supplemented, and premixes are added to home-mixed concentrates in small quantities so that the ration supplies all essential minerals.

Good practice when feeding concentrates includes:

• Introduce them gradually over about one to two weeks, to let the rumen microbes adjust and to prevent acidosis.
• Feed in two or more smaller meals a day rather than one large meal.
• Always provide enough forage, because too little fibre lowers rumen pH and reduces milk fat.
• Store in a dry, ventilated, rodent-proof store to avoid moulds and aflatoxin contamination.
• Weigh the feed for each animal according to its production rather than feeding by guess.

2.1.3.2 Forage

Forage is the main and cheapest feed for ruminants and supplies the fibre that keeps the rumen working properly. Forage may be grazed fresh, cut and carried to the animals, or conserved for periods when feed is scarce. Example: a mixed farmer with a small plot may grow Napier grass and Desmodium for cut-and-carry feeding of dairy cows, and conserve surplus as silage for the dry season.

The main forms of forage are:

• Grasses: Napier grass, Rhodes grass, Kikuyu grass and Brachiaria supply energy and fibre. Quality falls quickly as the plant matures, so they should be cut or grazed at the right stage.
• Legumes: Desmodium, lucerne and Sesbania are rich in protein and minerals and improve soil fertility through nitrogen fixation. Mixing legumes with grasses raises the protein level of the diet.
• Browse and fodder trees: Calliandra and Leucaena leaves are valuable protein supplements, especially in dry areas where grass quality declines.
• Fodder crops: Crops such as fodder sorghum and oats are grown specifically for feeding and can be fed green or conserved.
• Crop residues: Maize stover, wheat straw and sugarcane tops have low protein and energy but are vital feed resources in the dry season. They need treatment or supplementation to improve digestibility and nutrient availability.
• Hay: Forage cut at a suitable stage and dried until it can be stored without moulding. It must be kept dry and off the ground.
• Silage: Chopped green forage such as Napier grass or maize stalks, packed tightly and sealed to exclude air so that it ferments and keeps. Adding molasses supplies sugar for fermentation and improves quality.

Forage quality depends on the species, stage of growth at harvest, soil fertility and the method of conservation. Forage cut when young is more digestible and higher in protein than forage cut when mature and stemmy.

2.1.3.3 Pastures

A pasture is an area of land planted with or naturally covered by grasses and legumes that animals graze directly. Pastures are the cheapest source of feed because the animal harvests the feed itself, but they need good management to stay productive. Example: a dairy farmer may divide a Rhodes grass and legume pasture into paddocks and move cows from one paddock to the next so that each area has time to regrow.

Pastures are of two main kinds:

• Natural pastures: Indigenous grasses, herbs and shrubs growing without sowing, common in rangelands and pastoral areas. Productivity depends on rainfall and falls sharply in the dry season.
• Improved or sown pastures: Established with selected species such as Rhodes grass, Kikuyu grass, Star grass, Brachiaria and legumes such as Desmodium, lucerne and clovers. They give higher yields and better quality than natural pastures when well managed.

Key practices in pasture management are:

1. Prepare a fine, weed-free seedbed and sow or plant at the onset of reliable rains.
2. Mix grasses with suitable legumes to improve protein content and soil fertility.
3. Allow the pasture to establish fully before the first grazing so that the plants are not uprooted.
4. Set the stocking rate according to the pasture's carrying capacity, because overstocking leads to overgrazing, bare ground and erosion.
5. Use rotational grazing in paddocks, giving each paddock a rest period to regrow.
6. Graze at the right stage, when the grass is leafy and has not become stemmy, for the best intake and digestibility.
7. Apply manure or fertiliser as needed and control weeds to maintain productivity.
8. Watch for bloat when animals graze young, wet, legume-rich pasture, and introduce animals to such pasture gradually after feeding them some dry forage.

Chapter Summary

This chapter covered the various types of ruminant feeds including concentrates, forage, and pastures, highlighting their roles in providing essential nutrients for animal growth and production. It addressed the principles of feed formulation, emphasizing the need to balance nutrient content to meet the specific dietary needs of ruminants. The discussion included factors that determine the nutritional requirements of animals such as age, weight-stage of production, and health status. Methods for preparing accurate feeding records were presented to ensure proper monitoring and management of feed intake. Students learned how to formulate appropriate feed rations tailored to the needs of different ruminant animals. The chapter also explained practical feeding techniques to optimize animal performance and welfare. Finally, it reinforced the importance of maintaining detailed feeding records to track diet effectiveness and support decision-making in ruminant feeding management.