Ruminant Nutrition

Flashcards on ruminant nutrition covering beef cattle, dairy cattle and small ruminants.

Production Animal Rations

Designed for feeding groups, assuming animals eat a predictable percentage of BW in dry matter. Different rations are made for different groups (e.g., dry cows vs. early lactation cows).

Beef Cattle Nutrition Goals

Focus on meat production, average daily gain (ADG), and reproduction.

Beef Cattle Energy System

Uses metabolizable energy (ME) as a key metric.

Key Nutrients for Beef Cattle

Energy, protein (CP and UDP), dry matter, Mg, Co, and Vitamins A/D/E.

Nutritional Diseases in Beef Cattle

Grass tetany and rumen acidosis are examples.

Beef Cattle Feeding Characteristics

Foragers with a mature body weight of 600+ kg and a rumen capacity of 100-180L.

Beef Cattle Oral Anatomy

8 lower incisors, dental pad, and 24 premolars/molars. They are less selective and eat more fibrous forage.

Beef Cattle Salivary Glands

Produce 50-150L saliva/day containing bicarbonate, phosphate, urea, lipase, and antibodies. No amylase is present, but mucin acts as an antifoaming agent.

ME Calculation for Beef Cattle

ME = 0.1W + 8 (in MJ); x2 for rapid growth and pregnancy, x1.3 for late pregnancy.

Dry Matter Intake Calculation for Beef Cattle

Max DM Intake (% of body weight) = 120/NDF%. Higher quality feeds increase feed intake.

Vitamin Requirements for Beef Cattle

B vitamins, C, and K are often microbially synthesized or endogenously produced. A, D, and E requirements vary based on lifestage and production.

Feedlot Advantages

Quickly bring cattle to market weight, provide a uniform product with higher fat content, and reduce pasture stocking.

Feedlot Disadvantages

Overcrowding increases disease risk, high grain diets can cause disease, and there are potential environmental impacts.

Feedlot Timeline

Includes cow-calf operation, backgrounding/stocker operation, and stockyard phases with specific weight and feeding goals.

Transitional Feeding

Slow diet changes from pasture to feedlot to avoid health consequences like rumen acidosis, starting with a ration of 50-70% roughage.

Growth Stimulants

Implants (steroidal and non-steroidal) and ionophores can improve ADG and feed conversion ratio (F/G).

Hypomagnesemia (Grass Tetany)

Caused by low Mg absorption, often due to N and K fertilizer use. Signs include excitability, and treatment involves parenteral Mg + Ca.

Ruminal Acidosis

Occurs with high NSC feeding, leading to increased VFA production. Subacute (SARA) results in rumen pH <5.5, while acute (ARA) leads to rumen pH <5.

Feeding Rules of Thumb

Energy ~0.1(W) + 8 MJ/d,Adjusted for growth, reproductive status. TDN 70-85% .Crude Protein 7-20% .UDP 20-40% based on lifestage

Dairy Cattle Nutrition Goal

Maximize milk production and ADG for heifers/calves.

Dairy Cattle Energy System

Uses metabolizable energy (ME) and net energy for lactation (NEL).

Nutrients of Concern for Dairy Cattle

Energy, protein, calcium, phosphorus, and magnesium.

Nutritional Diseases in Dairy Cattle

Milk fever, ketosis, and displaced abomasum (LDA).

Dairy Cattle Feeding Characteristics

Foragers, less selective, and eat more fibrous forage. Salivary glands produce 100-300L saliva/day.

Milk Composition

80-85% water, 3.5-5% fat, 3-4% protein, 4.6-5% lactose, and 0.7% vitamins/minerals.

Dairy Cow Calendar

Lactation period of ~300-305 days, followed by a dry period of ~60-65 days. Mating occurs at 85 days.

ME Calculation for Dairy Cattle

Energy Maintenance ME = 0.09W + 9.5 (in MJ) plus additional ME for gestation, activity, milk production and weight gain

High Producing Cows Need High Energy

Low energy can result in Displaced Abomasum,Acidosis, Ketosis and Low milk fat.

Milkfat Depression

Reduction of milkfat (≤2%) from high polyunsaturated FA, Low fiber, high concentrates. Treatment: Adjust ration

Parturient paresis/ Milk Fever

1-3d post calvingCa from blood à milk. Treatment: IV/oral Ca; ReduceDCAD

Ketosis/Fatty Liver

Glucose deficiency results in fatbreakdown.Fats are converted to ketone bodies

Small Ruminant Nutrition Goals

Meat (lambing), fiber (sheep), and milk (goats).

Energy System for Small Ruminants

Uses ME and TDN.

Key Nutrients for Small Ruminants

Energy, protein, and minerals (copper, cobalt, sulfur) along with vitamins (thiamine, fat solubles).

Nutritional Diseases in Small Ruminants

Copper toxicity, polioencephalomalacia, pregnancy toxemia, and hypomagnesemia.

Feeding Characteristics of Sheep and Goats

Sheep are foragers and intermediate feeders, while goats are browsers. They have a rumen capacity of 2-15L.

Vitamin and Mineral Requirements for Small Ruminants

B vitamins, C, and K are microbially synthesized, while A, D, and E requirements vary based on lifestage.

Nutrients Affecting Fiber Growth

Energy (limiting), Protein (cysteine and methionine), Vitamins and Minerals(zinc, copper, selenium.cobalt, iodine)

Copper Deficiency

<5mg/kg feed. Signs: Poor wool. Poor connective tissue and bone , Pigmentation (tyrosinase). Anemia (ferroxidase)Nerve disfunction

Copper toxicity

≥10 mg/kg feed. Signs: Hemolytic anemia.Hemoglobinuria. Liver signs

Polioencephalomalacia (Sheep)

Cerebrocortical necrosisAssociated with high sulfur levels. Signs: agitation, anxiety, “stargazing” death