Effect of breed and age on the voluntary intake and the micromineral status of non-pregnant sheep: 1. Estimation of voluntary intake
Twenty-four sheep were used to test breed and age differences in voluntary intake (VI). The sheep were divided into four groups of six animals each: Suffolk mature ewes (SM), Suffolk yearlings (SY), Rambouillet mature ewes (RM), and Rambouillet yearlings (RY). The animals grazed alternatively two mi...
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Published in | Small ruminant research Vol. 37; no. 3; pp. 223 - 229 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Netherlands
Elsevier B.V
01.08.2000
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Subjects | |
Online Access | Get full text |
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Summary: | Twenty-four sheep were used to test breed and age differences in voluntary intake (VI). The sheep were divided into four groups of six animals each: Suffolk mature ewes (SM), Suffolk yearlings (SY), Rambouillet mature ewes (RM), and Rambouillet yearlings (RY). The animals grazed alternatively two mixed pastures containing
Trifolium repens latum,
Lolium perenne and
Pennisetum clandestinum from 07:00 to 16:30 hours and remained penned overnight. Voluntary intake was estimated using chromic sesquioxide (1
g per sheep) as an external marker, administered in two gelatin capsules, one before and one after grazing, during 65 days. Faecal grab samples were collected directly from each animal for three consecutive days beginning on Day 7 of the experiment and at 14-day intervals until Day 65 (sampling times=5). Hand-plucked samples of forage were used to estimate in vitro dry matter digestibilities (IVDMD), which were used with estimates of fecal output to calculate intakes (per animal and per kg of metabolic body weight (kg
0.75)). The data were analyzed as a completely randomized design in a factorial arrangement with repeated measurements. Voluntary intake, expressed both per animal and per kg
0.75, showed a breed×age interaction (
P<0.001). Suffolk mature ewes had the greatest daily VI (1.88 versus 1.26
kg
DM/animal for the other three groups) because they were the heaviest animals, but their VI/kg
0.75 (0.071
kg
DM/day) was not different (
P>0.05) from that of RY (0.063
kg
DM/day), which were smaller, younger animals. Suffolk yearlings and RM had similar VI/kg
0.75 (0.057 and 0.051
kg
DM/day, respectively), not different from that of the RY. Intakes showed a cubic trend (
P<0.001) with time, possibly because of changes in IVDMD and climatic conditions. The lower intake, yet better gains of RM and RY indicate a greater ability to thrive under conditions of average pasture quality. High forage availability did not result in greater forage consumption. The information on VI was later used to assess the micromineral status of the sheep in the experiment. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0921-4488 1879-0941 |
DOI: | 10.1016/S0921-4488(99)00141-8 |