Sheep - AgRIS

Table 6.10 Means with standard errors for wool production and quality attributes of Nilgiri
and its crosses with Soviet Merino and Rambouillet
Genetic group Annual greasy Average fibre Staple Medullation fleece production
(kg) diameter(µ) length (cm) (%)
Nilgiri 1.285±0.076 22.158±0.050 6.166±0.035 5.13
(57) (57) (57)
Merino x
Nilgiri (1/2) 2.860±0.043 21.527±0.030 7.523±0.030 Nil
(239) (112) (112)
Merino x
Nilgiri(l/2) 2.689±0.120 21.237±0.080 7.364±0.043 Nil
(30) (30) (30)
Merino x
Nilgiri (3/4) 3.470±0.106 20.254±0.035 8.007±0.035 Nil
(45) (45) (45)
Nilgiri(3/4interse) 3.825±0.168 20.193±0.113 7.105±0.140 Nil
(4) (4) (4)
Merino x
Nilgiri (5/8) 3.264±0.069 20.784±0.041 6.647±0.034 Nil
(98) (41) (41)
Merino x
Nilgiri (5/8 interse) 3.341±0.122 20.372±0.036 7.564±0.036 Nil
(53) (53) (53)
Rambouillet x
Nilgiri (1/2) 2.508±0.041 21.946±0.033 7.219±0.028 2.14
(194) (92) (92)
Rambouillet x
Nilgiri (F 2 ) 2.500±0.188 21.751±0.096 7.982±0.006 Nil
(12) (12) (12)
Rambouillet x
Nilgiri (3/4) 2.900±0.463 20.265±0.133 7.616±0.074 Nil
(06) (06) (05)
Note: Figures within parentheses are number of animals.
6.2.2.3 Mutton production
Mutton production, a polygenic trait, is mostly governed by additive gene action. The
characters connected with mutton production, viz. body weightslbody weight gains, efficiency
of feed conversion and dressing percentage are moderate to highly heritable and thus the
selection within the indigenous breeds can bring about considerable improvement in mutton
production. Some of the Indian breeds like Mandya are quite comparable to most of the exotic
mutton breeds with regard to their dressing percentage. However, selection within the natives is
somewhat slow in bringing about desired improvement in the mutton production because of
extremely low level of their present production. Improvement of inferior native breeds through
upgrading with relatively superior native breeds or through crossing native breeds with exotic
superior mutton breeds will prove to be a better alternative for bringing in more rapid
improvement. Little efforts were made earlier to breed sheep exclusively for mutton. One such
attempt was made by ICAR at Punjab Agricultural University, Punjab in the later half of 1960
and now under the AICRP on Sheep Breeding for the development of mutton breeds which
proved to be economical under stall-fed conditions. Besides breeding sheep for improvement of
wool production, there has also been a tendency to look into the improvement of live weight
alongwith wool.
Studies on the purebred performance of native breeds
Weighted averages and the corresponding standard errors for body weight at different ages,
efficiency of feed conversion and carcass yield in North Western carpet wool breeds and
Southern mutton type breeds are given in Table 11.1. The estimates of heritability and genetic
and phenotypic correlations of body weight at different ages in various breeds are presented in
Tables 11.2 and 11.3. Perusal of the tables revealed, the North Indian carpet wool breeds to be
heavier in body weight than south Indian mutton breeds. Efficiency of feed conversion of two
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