Pak Dairy Info
Pakistan's 1st Online Dairy Farming Guide

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Contents

Introduction

Breeds

Selection of Animals

Farm Building

Management

Record Keeping

Sanitation & Hygiene

Nutrition

Reproduction

Breeding

Health

Body Condition Scoring

Milk Quality

Feasibility

Terminologies

Directory

Picture Gallery

Correction Factors

Good culling decisions depend on the ability to compare accurately the performance of individuals or groups of animals. To accomplish this, all records must be adjusted or corrected to a comparable basis. Correction factors have been developed to adjust for the length of lactation, the number of milkings per day, age and month of calving, and the fat content of milk. These four adjustments are necessary for comparing the milk and fat of dairy animals managed under different environmental conditions.

Length of Lactation:
The most generally accepted standard length of lactation records is 305 days. When an animal is milked longer than 305 days, her yield for the first 305 days is used as the standard lactation yield. The factors commonly used are:

Days milked

Factor

95

2.82

125

2.16

155

1.77

185

1.51

215

1.32

245

1.18

275

1.08

 

 

Number of Daily Milkings:
Most dairy animals are milked twice daily (usually referred to as 2 x). Hence, for most lactations, no adjustment is necessary. To convert three-times-a-day milking to a two-times-a-day basis, multiply by 83% (0.83).

Age and Month of Calving:
The age of a dairy animal, as a rule, is always based on her age when she calved, which is when her record officially begins. In most of the western countries, at 2 years of age a cow produces about 70 to 80% of her mature production; at 3 years, 80 to 90%; at 4 years 90 to 95%; at 5 years, 96 to 100%; and at 6 years, she reaches her mature record. Age-adjustment factors have been developed to standardize 305-day lactation records to a mature equivalent basis and to minimize environmental variation due to the month of the year in which the record began.

Fat-Corrected Milk (FCM):
For comparative purposes, the fat content of milk is usually based on calculating the milk and fat production to 4% fat (4% FCM), but it may be calculated to any desired fat basis. The formula for 4% FCM is:

4% FCM = (0.4 x milk weight) + (15 x fat weight)

 

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