India is the richest country in the world in livestock wealth. However, meat
production is largely a by-product of livestock production system. More than
40% of the total meat is produced from spent (culled) animals at the end of
their productive economic life (Mendiratta et al.,
2008). Sheep are also usually reared for wool and are slaughtered at the
end of their productive economic life. Meat production in India is far below
the level of demand from the huge population. Per capita necessity of meat consumption
in India is 34 g as recommended by Indian Council of Medical Research, however,
the present availability (16 g) is much below that (Mathur,
Mutton (sheep meat) or Chevon (goat meat) is highly preferred by Indian consumers
due to excellent flavor and palatability. However, availability of chevon or
mutton is very less and chicken is taking the major share of Indian meat market.
Lower production of chevon or mutton coupled with high market price due to demand
supply gap has originated from lower emphasis in production and development
of sheep and goat in the country. Sheep occupy a special niche in the Indian
agricultural production system and are important for the rural economy. However,
the litter size of almost all Indian sheep breeds, except the Garole, is low
and is thus a major constraint to sheep-meat production. The Garole is the only
known prolific sheep breed in India (Pardeshi et al.,
Garole, a precious sheep breed from West Bengal an eastern province of India,
is having some outstanding genetic potentiality such as high fecundity and lambing
frequency. Its prolificacy, lambing frequency, disease resistance and other
extraordinary merits rarely observed in any other sheep breeds of the world
(Bose, 1995). Garole is a small coarse wool sheep breed
with short legs, weighing about 12-15 kg, average liter size 1.8. It has a special
gene Booroola fecundity commonly named as FecB gene which makes
it more prolific than other breeds and world famous Booroola-Merino sheep has
large litter size due to the same gene (Nimbkar et al.,
2003). Garole sheep are able to live in wet conditions of the delta which
typically lead to foot rot in other breeds, suggesting a genetic resistance
to some parasitic infections (Nimbkar et al., 2003).
As the area is coastal and saline other agricultural activity is not well adopted
hence this sheep provide principal source of income during agriculturally lean
period and govern socio-economic status of these sheep farmers of this region
Exploitation of the beneficial traits of Garole sheep will increase production
of sheep to few folds and the differential demand supply ratio of red meat of
the country can be decreased. Keen interest for the development of Garole sheep
has been taken by government, non-government and other international development
agencies (Banerjee and Banerjee, 2000). However, production
potential and quality assessment of mutton, skin and wool from Indian Garole
sheep are not properly studied and documented in the published literature. In
this paper we report production potential and quality of Garole sheep in its
native tract for mutton, skin and wool. We evaluated the basic quality of mutton,
skin and wool from the Garole sheep from different sources to establish the
basic data which will be useful for future research and for commercial utilization
of this promising sheep breed.
MATERIALS AND METHODS
This study was done during August, 2005 to March, 2007 for a duration of 1
year 8 months.
Meat, skin and wool samples were collected from the native tract of Garole
in Sunderban region and from Kolkata (about 100 km away from its native tract).
All the samples were collected from randomly selected healthy Garole sheep of
the age group of 8-12 months with body weight ranging between 9.09-10.67 kg
from the selected sources. Sheep were reared under uniform housing, feeding
and management conditions. Twelve sources were selected from three major areas
for sample collection: 1. Local markets (6), 2. Kolkata markets (2) and 3. Kolkata
slaughter houses (4).
Meat Quality Analysis
Total 60 meat samples (5 each from 12 different sources) were collected
for this study after hygienic slaughter from the selected sources as follows:
Local markets 30 samples (5 each from 6 different markets); Kolkata markets
10 samples (5 each from 2 markets) and Kolkata slaughter houses 20 samples (5
each from 4 place). About 100 g of Longissimas dorsi and Semitendinosus
muscle were collected as sample in food grade plastics and transported in icebox
to the laboratory. For the evaluation of carcass characteristics age at slaughter,
weight at slaughter, carcass weight were recorded during slaughter of animals
and dressing percentage was calculated as per standard procedure.
Meat quality parameters viz. pH, water holding capacity, muscle fiber-diameter
of meat samples were done following the standard procedure. For pH about 5 g
of meat sample mixed with 25 mL distilled water, homogenized at 3000 rpm for
1 min then pH was measured with the help of a digital pH meter (AOAC,
1995). For WHC Meat samples were weighed and wrapped with tissue paper,
centrifuged at 1000 rpm. for 4 min. After centrifugation meat samples were taken
out of tissue paper and weighed. Then samples were kept into hot air oven (70°C)
for 12 h then taken weighed again. Loss of weight in the second phase was expressed
as WHC in percentage. For refrigeration loss fresh meat samples were weighed
and kept in refrigerator at 4°C again weighed after 17 h. The difference
in pre and post refrigeration weight was expressed as the refrigeration loss
in percentage (Zhang et al., 1995). For muscle
fibre diameter 5 g raw meat from each sample was weighed, mixed with 30 mL 0.25
M chilled sucrose solution and homogenized at 5000 rpm for 1 min. A drop of
this mixture was put over a clean greeze free glass slide and air dried. Now
staining was done by methylene blue (0.3%) stain. After drying it was observed
under microscope at 100X and 450X magnifications. The fibre-diameters were measured
using oculometer on eyepiece (Davis et al., 1980).
Proximate analysis viz. moisture, protein, fat, ash and carbohydrate contents
of meat samples were estimated using modified official methods for raw meat
analysis (AOAC, 1995). The samples were dried in hot air
oven at 110°C for 16 h for moisture and the percent moisture was expressed
as the difference in weight of the sample before and after drying. Total fat
was extracted using soxhlet apparatus for 6 h with petroleum ether and the dried
residue was weighed for fat content. The fat free residue was split into two
portions. One was used for protein analysis by Kjeldahl method through digestion,
distillation and titration. Another portion of sample was used for ash estimation
by incinerating at 500°C for 12 h followed by cooling and weighing the ash
residue. Carbohydrate content was calculated from the difference between fat
free residue and ash plus protein. Mineral analysis for common macro and micro
minerals in Garole meat viz. sodium, potassium, calcium, phosphorus, magnesium,
iron, cupper, zinc, manganese and chloride contents were estimated following
the standard methods (AOAC, 1995). Sodium, potassium and
chloride contents were estimated by flame photometry (Systronics digital, FPM-125)
methodology and other minerals (Zn, Cu, Fe, Mn, Ca, Mg and P) were estimated
by using atomic absorption spectro-photometer (Parkin Elmer AAS-100) methodology
based on a standard curve of known standards.
Skin Quality Analysis
A total of 60 (5 each from 12 sources) skins from the same animals were
collected after the slaughter of Garole sheep at above mentioned slaughter points.
Skin quality was assessed by recording different parameters like skin length,
skin width, skin weight (wet and dry), total skin area, skin weight percentage
and skin defect.
Skin length and skin width was measured with the help of a measuring tape and total skin area was calculated by multiplying length and width. After taking the wet weight the skins were sundried with salting and dry weights were taken using weighing balance and skin defect was noted with physical inspection. Wet Skin weight was expressed in percent over body weight at slaughter.
Wool Quality Analysis
Five grams of wool samples were collected each from neck and buttock region
of 100 randomly selected sheep (total 200 samples) from its native tract, Kolkata
market and Kolkata slaughter points. Samples were collected in plastic packets
and transferred to the laboratory at normal temperature.
Different wool characteristics like fiber length, fiber diameter, type of fiber,
medullation, crimp/cm, bundle strength, elongation were assessed following standard
methods (Wang et al., 2007). Ordinary scale was
used for measuring fiber length and crimp; fiber diameter, fiber type and medullation
were assessed with the help of microscope and ocular micrometer (Wang
et al., 2007). Shearing time, duration of shearing and weight of
wool per shearing were recorded as per standard animal husbandry practices and
compared with normal sheep standards.
Data obtained were analyzed to determine the mean and Standard Error (SE)
for all parameters as per standard procedure (Snedecor and
Garole sheep are raised in free range system in the natural pasture land without technical inputs for feeding or management. Primarily these sheep are used for meat production, though it produces wool also but it is not properly harvested. We have surveyed the marketing pattern of Garole sheep. Garole sheep is usually slaughtered at 8-12 months age in local meat shop to meet the demand of red meat among local consumers. A major population of the sheep is sent to Kolkata Market either directly or indirectly via the local wholesale market and from their sheep is sent to four major slaughter houses in the city. Acceptance of mutton is poor at village level due to their ignorance about sheep meat; therefore, it is sold as goat meat unlike in metro city Kolkata. A total of 60 meat samples, 60 skin samples and 200 wool samples from Garole sheep were evaluated on basic quality characteristics in this study. The results are presented and discussed below.
Average dressing percentage of Garole sheep was 55.87% and it was little
higher in Kolkata slaughter houses than local or Kolkata markets. Average dressing
percentage of Garole sheep was higher than other sheep breeds (48-52%) which
indicates its better potentiality for meat production.
The different parameters related to meat quality viz., pH, WHC (Water Holding
Capacity) refrigeration loss, fiber diameter of Garole meat are shown in Table
1. Different quality parameters of Garole meat like pH (5.97), WHC (43.33%)
and refrigeration loss (0.86%) was little lower than normal values for mutton.
Average value of moisture, protein, fat, ash and carbohydrate was 76.02, 18.20, 3.53, 1.65 and 0.60%, respectively (Table 2). In comparison to average sheep standards, moisture and ash percent was higher, whereas, fat and protein percent was lower in Garole meat. Fat percent in Garole meat was significantly (p<0.01) lower and was almost half of normal sheep standard which indicates a great advantage to the modern consumer concerned about fat eating. There was no significant difference in terms of other parameters and were close to the normal sheep standards. Minute variations were found between sources of sample of Garole meat but there was no significant difference.
Average value of different mineral content like sodium, potassium, calcium, phosphorus, magnesium, iron, cupper, zinc, manganese and chloride contents of Garole meat are shown in Table 3. In general mineral contents were comparable to their standard value for mutton or at higher side.
The average value of skin length (61.43 cm), skin width (53.37 cm), skin
weight (wet-1.188 kg, dry-0.59 kg), total skin area (3403 cm2) and
skin weight percentage (12.02%) was good and comparable with valuable Bengal
goat skin. There was hardly any defect in skin, rarely slight perforations were
seen which might be due to ectoparasitic infection (Table 4).
|| Characteristics of Garole meat from different sources (Mean±SE)
|| Proximate composition of Garole meat from different sources
|| Mineral content of mutton from Garole sheep of different
|| Skin quality of Garole sheep from different sources (Mean±SE)
|| Wool quality of Garole sheep from different sources (Mean±SE)
|*Coefficient of variation
The value of different parameters determining wool quality is expressed
as average of wool collected from buttock and neck region of each Garole sheep
(Table 5). Overall average of different qualities of Garole
sheep wool like fiber length (4.95 cm), fiber diameter (54.77 μm) with
coefficient of variation of 57.48%, type of wool (carpet type), medullation
(88.13%), (crimp/cm (2.21)), bundle strength (7.36 g t-1), elongation
(29.56%) and weight of wool per shearing (308 g) are almost similar to common
sheep breed of India.
The dressing percentage was little lower in its native tract than Kolkata slaughter
houses might be due to humane slaughter, better dressing practices and economic
utilization of offals. In this study, dressing percent was slightly higher than
that of previous reports (Banerjee and Banerjee, 2000)
which might be due to prolonged fasting of animals during transportation before
slaughter in their study.
Parameters of different meat quality in Garole meat like pH, WHC and refrigeration
loss was little lower than normal values for mutton (Crosby,
2000). Lowered pH and WHC is good for appearance and juiciness of meat,
respectively and can prevent bacterial growth and meat spoilage (Watt
and Merrill, 1963). Therefore, these qualities coupled with lowered refrigeration
loss may improve shelf life of Garole sheep (Watt and Merrill,
1963). Average fiber diameter of Garole meat was also little lower than
known values for other sheep (Crosby, 2000). The lower
fiber diameter signifies more tenderness of Garole meat which plays most important
role in the acceptability of meat. However, in a different study (Banerjee
and Banerjee, 2000) it was reported that the Garole meat was slightly tougher
than goat meat which might due to higher age of the sheep selected for the study.
Meat is mainly composed of water, fat, protein, minerals (ash) and a small
amount of carbohydrate. Water is the most variable of these components, but
is closely and inversely related to the fat content. In Garole meat similar
relation is reflected by higher moisture content with a lowered fat percent.
The slightly lower level of protein content in Garole meat might be due to lower
nutritional status of the animals, since they are not reared under scientific
feeding. Difference of protein percentage in Garole meat was 0.7%, which was
slightly lower than other sheep meat. However, it should not be serious concern
for human consumption. Fat content is one of the most important concerns to
meat consumer due to its association with cardiac disease and obesity etc. Although
fat provides 2.25 times more energy than equal quantity of carbohydrate or protein,
animal fat is a source of cholesterol, which has got synergetic effect in heart
diseases and related circulatory disorders in human (Lawrie
and Ledward, 2006). Due to this reason, in spite of low palatability, people
prefer to consume white meat with low fat content (2-3%) avoiding red meat with
average fat content of 6-13%. Therefore, Garole meat can be considered as advantageous
to other red meat due to its lower fat content like white meat for human consumption.
Carbohydrate content is in consistent with the average sheep standards (0-1%).
In case of meat importance of carbohydrate is less. However, it serves an important
function in controlling physic-chemical properties of meat like pH and water
holding capacity (Lawrie and Ledward, 2006). Present results
suggest that the meat from Garole sheep is equivalent to mutton and in some
context is better for human consumption.
Higher value of ash content than normal sheep standards indicated higher mineral content in Garole sheep. Higher mineral content in Garole meat might be due to its adaptation in native coastal saline tract since long back.
Previously mineral study in meat was confined to five minerals like sodium,
potassium, iron, calcium and phosphorus. Recently Indian Council of Medical
Research strongly recommended that the magnesium, copper and zinc levels in
meat or meat products and baby foods should be monitored (Mathur,
2004). One of the important advantages of red meat is higher mineral content
particularly phosphorus, iron, zinc, manganese (Lawrie and
Ledward, 2006) which plays very important roles through vitamins and coenzymes.
The higher mineral content in Garole meat further emphasizes its nutritional
strength as a good source of dietary minerals essential for balanced diet.
The size of the skins of Garole sheep were quite optimum to fetch good price from the local leather market. Demand for good quality skin from indigenous sheep is very high which offers high market price. However, its marketing is neglected or not well developed till now which sometimes leads to lower price. The data generated in this work will provide better understanding about the quality of Garole sheep skin and may stimulate its utilization and marketing, however, research need to be done to assess its leather quality.
Shearing was uncommon in its native tract, although few non-government organizations
do it twice a year generally in the month of March and October. Wool was coarse
type and 59% were hairy. Wool quality evaluated in this study was in agreement
with the earlier reports (Banerjee and Banerjee, 2000).
Quantity of fiber per shearing estimated in this study was higher than the earlier
report of Bose (1995) and this difference might be due
to gradual improvement of management practices in its native tract and better
shearing by semi trained personnel from the non-government organizations. On
an average 600 g of wool can be obtained from each sheep per year from two shearing
which can fetch a very good economic return and need to be properly exploited
from Garole sheep of Bengal. The value addition and economic potentiality of
Garole fiber was also recommended earlier (Pan et al.,
2004). It is suggested that this hairy fiber should be extensively used
for production of carpets, blankets and other useful items which may generate
employment through byproducts industry. Small scale cottage industry should
be promoted to stimulate rural economy utilizing this Garole wool with self-help
group amongst educated unemployed.
It is concluded that the mutton from Garole sheep can be a good source of red meat with lower fat and adequate nutritive value and these qualities of Garole meat should increase the acceptance of consumers. This study provides better understanding about the quality of Garole sheep skin and may stimulate its utilization and marketing. The coarse wool fiber should be useful for carpets, blankets and other items which may generate employment through small scale cottage industry to stimulate rural economy.
The authors wish to acknowledge the technical suggestions and help rendered by Prof. S. Biswas, Prof. P. Biswas, Prof. T.K. Mondal, Chandrakanta, Siben and Manas of West Bengal University of Animal and Fishery Sciences, Kolkata, India. We also acknowledge the Department of Animal Resources Development and Paschim Banga Go-Sampad Bikash Sanstha of Government of West Bengal, India, for permitting to do this study.