Agriculture Reference
In-Depth Information
Table 13.1 Correction factors for 90-day
weaning weight due to litter size born and
weaned, dam age, and kid goat sex.
centrate feed that is balanced in energy and protein is more
effi cient than whole grain for growing goats, but the physi-
cal form of the concentrates as whole, rolled, chopped, or
other has little effect on growth and carcass traits.
Defi ciencies in energy from inadequate feed intake or low-
quality feed may cause decreased kid growth in size or
weight, delay in puberty, lowered fertility, depressed milk
production, and a lowered resistance to disease and para-
sites. Energy requirements are different with age, body
size, growth, pregnancy, lactation, weather, physical activ-
ity, and stress of meat goats.
The primary measurements of post-weaning growth are
weight gain per time period and weight per a specifi ed day
of age. Post-weaning ADG is a measure of the individual
animal's performance and the type of management prac-
tices in raising the goat.
The rate of tissue accumulation and the growth rate both
decline as maturity is approached and are also infl uenced
when does are pregnant or gestating. Lean tissues grow
proportionately faster than fat tissues early in post-wean-
ing growth, and fat tissues grow proportionately faster than
lean tissues later in post-weaning growth closer to maturity
so fat:lean and lean:bone ratios increase as goats mature
(Warmington and Kirton, 1990).
Effect of litter size
Number born
Number weaned
Correction factor
1
1
1.00
2
1
1.04
2
2
1.18
3
1
1.08
3
2
1.23
3
3
1.27
Effect of dam age, years
1
1.10
2
1.09
3 and older
1.00
Sex of kid goat
Buck
1.00
Doe
1.11
Wether
1.08
Source: Adapted from Browning, 2007 .
Post - Weaning Growth Restriction and
Compensatory Growth
Animals may not grow to reach their genetic potential if
stressor conditions such as nutritional restrictions or envi-
ronmental infl uences interfere with normal growth rates.
After removal of a nutritional defi ciency or other growth-
inhibiting conditions, the animal may increase the rate of
growth, or compensate, to counter the previous growth
limitations. This compensatory growth is often observed
as accelerated growth rate with adequate nutrition follow-
ing a period of feed restriction or nutrient defi ciency. The
increased growth may be due to increased dry matter
intake (DMI), improved feed effi ciency (FE), and/or
enhanced endocrine and biochemical reaction functions. A
restriction in growth early in the animal's life may result
in a permanent stunting of growth and development, par-
ticularly if organs do not grow and develop normally or
bones do not grow adequately to form the skeletal structure
for muscle and fat deposition. Generally, the briefer the
period of restriction and the older the animal at the time
of restriction, the greater is the chance for compensatory
growth to result in a similar mature weight as if no restric-
tion had occurred.
The ADG may be misleading if there has been compen-
satory growth during the period that the growth of the
These data show relative differences that a producer
might expect with sex, offspring numbers, and breeds, but
they should not be interpreted as absolute values for
growth that all kid goats will exhibit. Many genetic and
environmental factors will infl uence the pre-weaning
weights and growth parameters. Direct heritabilities from
two Boer goat herds were 0.33 and 0.36 for birth weight
and 0.27 and 0.60 for weaning weight (Schoeman et al.,
1997). Heterosis due to crossbreeding was observed in the
growth of females from 10-210 days of age while it was
not evident in males until the age of 90 days.
POST - WEANING PERFORMANCE
Strict attention to the behavior, health, and nutrition of kid
goats must be given during and immediately after weaning.
Kid goats must have access to feedstuffs and potable water
and be accustomed to receiving nutrition from sources
other than milk to maintain desired growth and develop-
ment rates. Post-weaning growth rate is less than pre-
weaning growth, probably due to a lower assimilation of
nutrients from solid feeds compared with milk (Warmington
and Kirton, 1990). Growth after weaning depends more on
the energy ingested or the level of food intake and less on
the method of feeding as ad libitum, restricted grazing,
intensive stall feeding, tethering, or other systems. A con-
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