Agriculture Reference
In-Depth Information
animal is evaluated. The weight compensation after
removal of the stressor may be equal to or part of the
weight gain that would be observed in unstressed animals.
Additional factors may affect the growth rates, compensa-
tory growth, and mature body weights for specifi c animals.
Post-weaning growth can also be infl uenced by the genetic
potential of the animal and environmental conditions.
Management practices that may alter growth and develop-
ment include breed selection, weaning age, castration,
climate control, type and availability of feedstuffs, stock-
ing densities and stocking rates, and mixed grazing with
other species.
will also have an infl uence. Examples of the types of
growth of some meat goat breeds are in Table 13.2. These
growth rates should not be interpreted as absolute but used
as a guide to the differences that can occur with different
breeds. Generally, the variations in growth rate among the
different animals within a single breed are as large as the
differences in average rates of growth among different
breeds.
Post - Weaning Growth Rate with Diet
G ROWTH WITH F ORAGE
Goats as ruminants can consume forage, browse, and con-
centrate feedstuff. Increased levels of poultry litter to
replace part of the concentrates in 80% concentrate and
20% millet hay diets decreased ADG in each period of
growth for Spanish and Spanish
Post-Weaning Growth Rate with Goat Gender
At 7 months of age, bucks weigh about 88-110
pounds (40-50 kg), and doelings weigh about 77-100
pounds (35 - 45 kg). Yearling bucks weigh 110 - 155
pounds (50-70 kg) and yearling doelings weigh 100-145
pounds (45-65 kg). Mature weights for bucks and does
are 200 - 285 pounds (90 - 130 kg) and 175 - 220 pounds
(80 - 100 kg), respectively. Breed differences, genetics
within breeds, nutrition, health and disease, breeding
age and method, and management systems will cause dif-
ferences in growth rates and body weights at any given
time.
Buck kid goats commonly grow up to 30% faster than
does during the post-weaning period. Intact male kid goats
grew to heavier weights (61.3 pounds, 27.8 kg) than cas-
trated males (48.3 pounds, 21.9 kg) and females (46.1
pounds, 20.9 kg) after feeding 0.5 pound of concentrate on
Argentine Bahia grass pasture (Johnson et al., 1995a). The
ADG on Marshall ryegrass pasture for 8 weeks was 0.31
pound (139 g) for buck kid goats compared with 0.15
pound (66 g) for wether kid goats (Solaiman et al., 2006).
In contrast, buck, doe, and wether Spanish kid goats had
ADG of 0.11 pound (49 to 51 g) when fed alfalfa and grass
hay diets supplemented with concentrate at 1.5% body
weight (Wildeus et al., 2007).
Boer kid goats com-
pared with control diets with no poultry litter (Negesse
et al., 2007).
Forage with higher nutritional value will provide greater
rates of growth than lesser feedstuff. Stocking rates and
pasture rotation will affect quality and quantity of forage.
Goats may selectively choose specifi c kinds and types of
supplements and forage, which will affect growth rates,
feed effi ciencies, and feed wastage. Increased energy in
the diet, particularly for goats on hay or pasture, will gen-
erally increase growth rate, but may also increase the
deposition of fat and decrease lean to fat amounts, depend-
ing upon the stage of growth of the meat goat. Goats are
generally not fed high-concentrate diets because of cost
and composition considerations. Additionally, goat kids
that exceed a market weight of 80 pounds (36 kg) will
receive a price penalty at marketing because the buyers do
not have markets that desire goats weighing more than 80
pounds.
Post-weaning ADG for goat kids fed warm season grass
pastures (bahiagrass), mimosa browse, and cool season
grass pastures (annual ryegrass) were 0.10 pound (46 g),
0.18 pound (83 g), and 0.31 pound (141 g), respectively
(Solaiman et al., 2006). Condensed tannins in some forage,
such as Sericea lespedeza , may limit consumption and thus
performance of meat goats. Supplementation of lespedeza
pastures with polyethylene glycol increased ADG of
Boer
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Post-Weaning Growth Rate with Goat Breed
Growth rate is closely related to mature breed size
(Warmington and Kirton, 1990). Boer × Spanish wether
kid goats were reported to have higher DMI and 30%
higher ADG than Spanish goats, but 23% lower ADG than
Boer goats at 7 months of age (Cameron et al., 2001). A
producer must be careful in comparing the growth of
animals of different breeds under different conditions,
even if the environmental differences are slight, because
growth and development may often be affected by a
genetic by environment effect. Heterosis or hybrid vigor
Spanish does 4 months of age (Merkel et al., 2003).
Goats have faster growth rates on improved pastures com-
pared with native pastures.
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G ROWTH WITH S UPPLEMENTATION OF F ORAGE
Crossbred Boer kid goats achieved heavier weights when
supplemented with concentrates compared with range only
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