Agriculture Reference
In-Depth Information
Table 7.9
The superovulation response, embryo recovery rate, and pregnancy rate in Boer and
indigenous feral goats following superovulation and embryo transfer.
Boer goats
Indigenous goats
Donor
Recipient
Donor
Recipient
Number of animals
Total number of CLs (ovulations)
CL/doe in estrus
Embryos recovered (%)
Classes I and II embryos (%)
Number of unfertilized ova (%)
Does pregnant (%)
8
70
a
18
a
94
a
97
a
2
a
(2.9)
20
60
a
16
205
b
15
a
80
a
64
a
2
a
(1.0)
40
67
a
a,b
Within rows, means with same superscripts are not signifi cantly different at 0.05 level.
Source: Greyling et al., 2002 .
Table 7.10
Mean (
SD) estrous response, onset
and duration of the induced estrous period in
Boer goat does superovulated with pFSH
(control) or pFSH/GnRHa protocols.
±
Table 7.11
Embryo grading for goats prior to
transfer or cryopreservation.
Grade/class 1
Embryos morphologically intact and
compact with morulae or blastocyst
Estrous
response
(%)
Time to
estrus
(h)
Duration
of estrus
(h)
Grade/class 2
Embryos (morulae to blastocyst) with
minor morphological deviations (few
extruded blastomeres)
Treatment *
N
Grade/class 3
Embryos (morulae to blastocyst) with
an uneven cell organization, loose
structures, and numerous free
blastomeres
pFSH (control)
11
100
30.6
±
9.1
18.2
±
3.7
pFSH/GnRHa
11
100
31.1
±
8.8
18.9
±
4.0
* No signifi cant differences
pFSH, porcine FSH; GnRHa, GnRH analog.
Source: Lehloenya, 2008 .
Degenerate
Embryos at 8 - cell stage or embryos
earlier (little or no cleavage)
Source: Lehloenya, 2008 .
season, the proposition of accelerated kidding (three times
in 2 years) is a defi nite option. The kidding season must
be selected to fi t in with the period when feed is most
plentiful, under intensive conditions with above average
management, then kidding can occur every 7-8 months.
However, in this practice, there are certain prerequisites
like high level of nutrition throughout, early weaning (± 2
months of age), and early reconception (within 90 days of
kidding). With accelerated breeding, the kidding rate
(number of kids born per does mated) can be increased to
well over 200% per year. Factors to be kept in mind when
implementing such a practice are that during certain
seasons the nutrition of the goats needs to be supple-
mented, and artifi cial breeding (synchronization and AI)
during at least one of the cycles may be necessary. The
Boer goat among others is one of the leading meat goats
worldwide that lends itself excellently to such an acceler-
ated kidding program (Erasmus, 2000; Malan, 2000).
Pregnancy Diagnosis in the Doe
Early detection of pregnancy in the doe has not only the
advantage of identifying nonpregnant females, but money
can be saved on feed costs (supplementary feed), and non-
pregnant does can immediately be remated or culled. By
the identifi cation of multiple births, feed and grazing can
also be used more effi ciently.
Ultrasonic scanning or sonography by means of the
sonar is a practical, inexpensive, and accurate means of
diagnosing pregnancy in goats. In practice, it is recom-
mended that does be scanned at approximately 6 weeks
following mating. Scanning in small stock is the most
accurate when performed between 42 and 100 days of
gestation. Besides the use of the abdominal probe where
does can be scanned in a standing position, a rectal probe
is currently also available. This probe provides a better
