Livestock feeding and environment Interaction

Ahsan Fayyaz

M.Sc (hons) Livestock Management

2003-ag-2079

ANFT-702

Dairy production causes unavoidable losses in Respiration Feces Urine

These act as Environmental burden and lead to the “greenhouse” effect (CO2 , CH4) or to the pollution of air (NH3), soil, surface, and subsoil water (NO3, P). Improved feed quality will reduce endogenous protein losses.

Introduction

Contributing factors

(Tamminga, 1992)

Greenhouse Effect Definition: The greenhouse effect is the heating of the

surface due to the presence of an atmosphere containing gases that absorb and emit infrared radiation. Thus, greenhouse gases trap heat within the surface-troposphere system.

In order of volume, Earth's most abundant greenhouse

gases are: Water vapors Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) Ozone O3 CFC’s (chlorofluorocarbons)

In 2009, nitrous oxide (N2O) was the largest

ozone depleting substance emitted through human

activities.

By their percentage contribution to the greenhouse effect the four major gases are:

water vapor, 36–70% carbon dioxide, 9–26% methane, 4–9% Ozone, 3–7%

Type of feeds

Nutrient categories:

1. Protein (of major concern)2. Carbohydrates3. Lipids4. Minerals

5. Vitamins

Protein Sources

Nitrogen: essential element in animal production. Large quantities of N are required for the growth of feed crops.

Crop N, primarily in the form of protein, is then an essential feed component for animal’s

Growth Development

Most of the N consumed is excreted by animals, providing manure nutrients needed for crop growth. The problem in this cycling of N is that large losses normally occur that contribute to the degradation of our environment.

(Rotz, 2004)

Eutrophication

Excess N or P water algae populations

decomposition dissolved oxygen

This is a major factor affecting the growth and reproduction of fish, clams, crabs, oysters, and other aquatic animal life. This algae bloom and subsequent decrease in dissolved oxygen is known as eutrophication.

Use of oxygen in water

P wastes

Inorganic supplements (P) excess P runoff potential environmental contaminant.

Simplest way to reduce P loss into environment is by feeding less P to animal.

Improved Diet and Feeding

Provide the right amount and quality of protein to maximize production at a minimum feed cost. As a result, less N is excreted and production may be improved.

Feed protein generally refers to crude protein. Crude protein is defined as N content times 6.25,

which assumes 16 g of N/100 g of protein in feeds. Proteins are composed of amino acids, which are

required for the maintenance, growth, and productivity of animals.

Less N excreted, less is the loss of N. Most excess excreted N is in a form that is easily transformed into ammonia.

(Han et al., 2001) Ruminally degraded protein (RDP) provides a mixture of

peptides, free amino acids, and ammonia for microbial growth and protein synthesis.

(NRC, 2001) Ruminally undegraded protein (RUP) is the second most

important source of amino acids that are absorbable within the intestinal tract.

Most forage protein is highly degradable, so there is normally little problem meeting the RDP requirement.

Total protein can be overfed to meet the minimum RUP requirement, but this leads to the excretion of considerable excess N. This excess N also requires energy to digest, which may reduce animal performance.

Solution Rumen-protected proteins Feed additives, such as enzymes, antibiotics,

probiotics, organic acids, and growth hormones, may also reduce N excretion. Enzymes can improve feed digestibility and nutrient availability.

(Han et al., 2001) Their effect on N excretion was in a range of 5-25%

reduction.

(Han et al., 2001) Growth hormones have had greater effects, reducing N

excretion by 12 to 38%.

(Han et al., 2001)

Environmental temperature Effects feed intake Comfort zone or zone of thermoneutrality

Comfort zone

Metabolic Rate

Environmental Temperature

(Cheeke, 1991)

In cold temperature Digestibility because passage rate through rumen is

increased Hormonal alterations (e.g. thyroxine; increases basal

metabolic rate) In wild ungulates; feed intake (survival on stored

body fat) Winter hair coat

(Cheeke, 1991)

In high temperature

Specific dynamic action (SDA) of feeds SDA is the extra heat produced from nutrient

metabolism and is higher for proteins esp. when deamination of amino acids is going on to convert ammonia to urea.

So, in high environmental temp. dietary protein must be reduced.

SDA is lowest for fat so, dietary fat content must be increased in high environmental temp.

(Cheeke, 1991)