Transcript No Slide Title

MEAT GOAT SIRE
EVALUATION TEST USING
THE GROWSAFE 4000
SYSTEM
David Seymour
WVU Extension Agent – Pendleton County
[email protected] 304-358-2286
Objective
• Determine the feasibility of adapting the
GroSafe system to meat goat bucks for
collecting data for a sire performance test.
GrowSafe System
GrowSafe Systems collect individual feed data to measure feed
efficiency in terms of net feed intake.
GrowSafe System
Adapting to Goats:
Was a challenge
GrowSafe System
(adaptive for goats)
2006 Buck Feeding Trial
• 23 commercial bucks from one commercial
herd were evaluated on the GrowSafe
system for 41 days.
• ADG ranged from 0.46 to 1.12 lbs/day with
the group averaging 0.67 lbs/day.
• Ultrasound carcass data from the rams on
the trial, adjusted to 80.43 pounds, ranged
from 0.04-0.12 inches for backfat and 1.271.93 square inches for LEA.
What makes this performance test
unique?
• Feed Efficiency Data / Residual Feed
Intake (RFI)
Understanding RFI and its
Implications
Residual Feed Intake
ADG →
Relationship of ADG w/ Maturity
Must grow to larger
size to equal stage of
finish. i.e. greater
mature size
Physiological maturity →
Genetic Scaling Theory
• Increased growth rate leads to increased mature
weight and a consequent increase in maintenance
requirements.
• In most ruminant production systems 65-75% of
the total lifetime dietary energy is used for
maintenance
– Only 5-22% is used for protein deposition.
– Maintenance energy requirements have been shown to
be moderate to highly heritable (h2=0.22-0.71)
If so important then why have we
waited until now?
• Difficulty in obtaining necessary
measurement:
– Gain
– Individual feed intakes
• ??? validity of data under non-production
environment.
• Understand what the data means and what
concerns there are with the data generated.
Efficiency of Conversion of Feed
• RFI (actual – expected)
– Considerable individual animal variation in
feed intake above and below what is expected
based on size and growth
RFI –The Practice
• Increase in weight over time is measured with
multiple observations and modeled by regression.
– Normalization of the growth curve to avoid periods of
morbidity or restriction.
– Initial weight, ADG, midpoint weight and final weight
are calculated from the regression.
– Intake is regressed on mid BW + ADG
• Mid BW is very important!
• This gives us an expected value for animals of similar weights
and rates of gain.
RFI – The Theory
• RFI is independent of growth and maturity
patterns.
• RFI is a more sensitive and precise measure of
feed quality based on energy intake and
requirements.
• Uses accurate contemporaries for comparison
– Positive RFI indicates less efficient use of energy
compared to contemporaries
– Negative RFI indicates greater efficiency
• RFI has been shown to have a heritability
coefficient near .45, similar to growth.
Results
• Residual Feed Intake (RFI), ranged from
3.24 to (-)2.54 lbs/day. The buck with the
RFI value of (-) 2.54 was more efficient and
consumed 2.54 pounds less feed than was
expected per day.
• Difference between the most and least
efficient bucks was 5.78 lbs of feed per day
(a cost of $ .65 per day
Result
• The trial demonstrated the GroSafe feeding
system with modifications can be used to
test meat goats.
Questions??