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Cobb Mx Male Management Supplement_Layout 1 29/03/2016 07:55 Page 5
Cobb MX Male Management Supplement
The body weight development in the first 12 weeks determines most of the frame size later
in life. The heavier males will develop the largest frame size, so the male weights need to
be kept very close to the recommended body weight from 4 through 16 weeks of age.
One way to do this is to separate the heaviest males at 3 to 4 weeks of age, by weight
grading, and then controlling the male body weight in the growing period.
This can be followed by a repeat grading at 8 weeks of age, handling all the males in the
flock and removing obvious visual (phenotypic) faults; i.e., crooked and bent toes, spinal
abnormalities, eye and beak abnormalities.
Uniformity is more and more important with the higher yielding males of today, not only to
have a uniform distribution of the female numbers per male in production, but also to
control the size of the male. With slats in production, males maintained close to the Cobb
standard weight will produce fewer leg problems and result in better overall fertility. With
floor operations, a larger male can be used as long as the breast muscle is not oversized,
which can create stability and fertility problems.
After 15 weeks of age, stimulate the males constantly with feed to maintain body weight
and testes development. Any severe stress or drop in body weight or even stagnation of
growth, especially from 15 to 25 weeks of age, will result in smaller and less uniform testes
in the males. This can result in lower initial hatches and a reduced fertility throughout the
production period.
Performing a male grading at 15 -16 weeks based on breast condition and/or wing
resistance allows the least developed males to be separated into a pen by themselves and
given additional feed to help improve sexual development and conformation uniformity.
The goal would be to have 95 % of males properly conditioned at 21 weeks of age.
Transferring from rearing to production houses
The single most important factor in determining the correct ratio is male quality at
housing.
Select only healthy males with no obvious skeletal defects.
For best results, keep the “average” weight population by removing extremely underweight
and overweight males. (The heavy ones would be ideal for spiking). Removing poorly
conditioned, extremely big males or males with skeletal or leg problems should be done
frequently and is essential to maximize fertility. Aim to match heavier groups of males with
heavier females and light males with light females. It is important to ensure a proper
synchronization between male and female sexual maturity and a proper body weight
differential. This helps with hen receptivity and mating efficiency.
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COBB