Research Results - (PDF, 101 mb) - USAID

of cottonseed meal/day between week five and
16; ewes in C received the same supplement as B
in addition to 200 g barley/day from week nine
to 16. During the 17th and 18th week, all ewes
remained on stubble while receiving the same
supplementation as treatment C. From the end
of the 18th week until lambing, ewes from all
treatments were pen-fed the same diet formulated
to meet their energy and protein requirements.
Stubble biomass and ewe weight were
measured every four weeks and extrusa samples
collected from esophageally fistulated rams.
Total stubble dry matter decreased from
6.5 T/ha at the beginning of the trial to 1.94 T/
ha after 16 weeks of grazing (P< 0.001). Treatment
had no effect (P > 0.05) on biomass.
Stubble quality only was affected (P < 0.001) by
period of grazing. Crude protein content (%of
organic matter) and in vitro organic matter
digestibility of extrusa samples collected during
the third, 11th, and 15th week were, respectively,
7.26, 61.5%; 6.11, 57.5%; and 5.50, 51.0%.
After 16 weeks of grazing, ewes in treatment A
had lost 6.2 kg whereas those in B and C gained
respectively 3.8 and 5.0 kg. Regardless of breed,
conception rate was slightly lower in A than B
and C (respectively 81, 91, and 88%). Prolificacy
did not change.
These results suggests that protein and
energy supplementation of ewes after the first
month of stubble grazing is necessary and may
improve their fertility.
1990 Trial
Forty-eight crossbred ewes (twenty-four
F1 and F2 D'Man x Sardi and twenty-four 3/4
Sardi x 1/4 D'Man) were randomly assigned to
two treatments, A and C (two replicates/treatment).
Stocking rate was set at 16 ewes/ha.
Ewes in treatment A did not receive any supplementation
during the first 16 weeks of grazing.
Those in C were moderately supplemented with
protein (after the fourth week) and energy (after
the eighth week). Mating started two weeks
after grazing started and lasted eight weeks.
Endoscopy was conducted to determine the
ovulation rate. Ewes were weighed (on two
consecutive days) at week 0, 2, 4, 8, 10, 12 and
56
16. Stubble biomass was measured at the
beginning of the trial and every four weeks
thereafter. At the end of the 16 week grazing
period, all ewes were pen-fed the same diet
(straw, alfalfa hay and concentrate) until lambing.
Data related to prolificacy and lamb weight
at birth are being collected. Lamb growth and
ewe performance are being monitored until the
third month after lambing. After lambing, ewes
from all treatment groups will be fed the same
diet.
b. By-Product Evaluation and Utilization for
Fattening Lambs
Source and Level of Nitrogen in Diets Containing
Carob Pulp for Fattening Lambs
The objective of this trial was to evaluate
the effects of nitrogen source (urea or sunflower
meal) and level of crude protein (12, 14, or 16%)
in diets containing relatively high levels of carob
pulp (30%) on digestibility and fattening performance
of laA:; Thirty-two crossbred wether
lambs (Sardi X lYMan) with an average initial
weight of 26 kg were used. Four balanced
groups of eight animals were randomly assigned
to four diets (A, B, C, or D). Diet composition
is shown in table 1.
Table 1. Composition of four diets fed to
crossbred wether lambs.
Ingredients, % A B C D
Carobpulp 30 30 30 30
Alfalfa hay 25 25 25 25
Barley grain 39 38.9 38.6 24.8
Sunflower meal 4.0 3.3 2.8 18.2
Mineral mix 2.0 2.0 2.0 2.0
Urea - 0.8 1.6 -
Diet crude protein, % 12 14 16 16
In diets B and C, urea provided 2 and 4%
crude protein (CP), corresponding to 16 and
28% of total dietary nitrogen. Each lamb was
housed separately and pen-fed individually.
After 15 days of adaptation, lambs were fed ad
libitum for 15 weeks, and intake and lamb
weight changes were monitored. Diet digestibil­