PERFORMANCE OF GROWING AND FATTENING YANKASA RAMS FED DIFFERENT PROPORTIONS OF UREA TREATED RICE STRAW AND GAMBA HAY

ABSTRACT
Two trials were conducted for a period of 90 days each to evaluate the feeding value of
different proportions of urea treated rice straw and gamba hay in the performance of
growing and fattening Yankasa rams. In the first trial, twenty four (24) growing Yankasa
rams of mean initial body weight of 15.77±2.5 kg and aged 6 – 8 months were allotted to
four dietary treatments with six (6) animals per treatment in a Completely Randomized
Design. Urea treated rice straw and gamba hay proportions of 0:60, 20:40, 40:20 and 60:0
were used as roughage diets. A concentrate diet consisting of maize grain, cotton seed
cake, rice milling waste, wheat bran, bone meal and salt was formulated to contain 15 %
crude protein. The animals were fed roughage diets ad libitum while concentrate was fed
at 1.5% of individual body weight. Data were collected on growth performance and blood
profile. Data generated were subjected to analysis of variance and differences in means
were compared using Duncan’s Multiple Range Test. The result of chemical analysis
showed that treatment of rice straw with urea increased its crude protein content from
3.64 to 8.89 % and decreased the neutral detergent fibre content from 72.16 to 67.98 %.
Total dry matter intake varied from 263.11 to 325.01 g/day with the highest value
recorded in animals fed 60:0 UTRS:gamba hay diet. Results of crude protein and neutral
detergent fibre intake followed similar pattern. The highest (P<0.05) average daily gain
(79.81 g/day) was obtained in growing rams fed 60:0 UTRS:gamba hay diet while the
lowest (P<0.05) value (44.44 g/day) was obtained in animals fed 0:60 UTRS:gamba hay
diet. Growing rams placed on 60:0 UTRS:gamba hay diet had the lowest (P<0.05) feed
conversion ratio value (7.77). Dry matter digestibility was significantly (P<0.05) affected
by UTRS:gamba hay proportions. Animals fed 60:0 UTRS:gamba hay diet had a high dryxviii
matter digestibility (67.62%). The digestibility of other nutrients followed the same
pattern. Animals fed 60:0 UTRS:gamba hay diet had significantly (P<0.05) higher
nitrogen intake (16.12 g/day) and the lowest (P<0.05) in the diet containing 0:60
UTRS:gamba hay (12.06 g/day). Nitrogen balance significantly (P<0.05) differed across
the dietary treatments. Animals fed diet containing 60:0 UTRS:gamba hay had high
nitrogen retention (13.30 g/day) while those fed 0:60 UTRS:gamba hay diet had low
nitrogen retention (7.78 g/day). With exception of serum creatinine, all the serum
parameters measured were significantly (P<0.05) different. Animals on 60:0
UTRS:gamba hay diet had higher (P<0.05) value of serum glucose (61.02 mg/dl) while
animals fed 0:60 UTRS:gamba hay diet had the lowest (P<0.05) value (49.55 mg/dl).
Serum urea nitrogen and total protein followed similar pattern. In the second trial, twenty
(20) intact Yankasa rams with mean initial body weight of 21.87±2 kg and aged 12 – 18
months were allotted to four dietary treatments with five (5) animals per treatment in a
Completely Randomized Design. Urea treated rice straw and gamba hay proportions of
0:60, 20:40, 40:20 and 60:0 were used as roughage diets. A concentrate diet consisting of
ingredients similar to those of the first trial was formulated to contain 13 % crude protein.
The animals were fed roughage diet ad libitum while concentrate was fed at 2.0 % of
their individual body weight. Data were collected on growth parameters, serum blood
profile and rumen liquor metabolites. Data generated were subjected to analysis of
variance and differences in means were compared using Duncan’s Multiple Range Test.
The result of chemical analysis of the experimental diets was similar to that obtained in
the growth trial. The result revealed that, there were significant (P<0.05) differences on
all the growth parameters measured. Total dry matter intake was significantly (P<0.05)xix
higher (1035.98 g/day) in animals fed diet containing 60:0 UTRS:gamba hay compared
to those fed the rest of the diets. Similarly, animals fed 60:0 UTRS:gamba hay diet had
high average daily gain (72.89 g/day) compared to animals on other diets. Lowest
(P<0.05) value (38.00 g/day) was recorded in animals fed 0:60 UTRS:gamba hay diet.
Rams fed 60:0 UTRS:gamba hay diet had the least (P<0.05) feed conversion ratio (14.21)
indicating that animals on diet containing 60:0 UTRS:gamba hay were more efficient in
converting feed to live weight gain than animals fed other diets. Digestibility of nutrients
was significantly (P<0.05) different across the treatment groups. Total nitrogen intake
and nitrogen retention were significantly higher (P<0.05) in animals fed diets containing
60:0 and 40:20 UTRS:gamba hay. No significant (P>0.05) difference was observed on
rumen fluid pH while significant (P<0.05) differences were obtained on rumen ammonia
nitrogen and Total volatile fatty acids (TVFA). Animals fed 60:0 UTRS:gamba hay diet
had higher (P<0.05) rumen ammonia nitrogen and TVFA (27.80 mg/dl and 16.13
Mmol/l, respectively). Lowest (P<0.05) values (21.79 mg/dl and 12.98 Mmol/l,
respectively) were obtained in rams fed 0:60 UTRS:gamba hay diet. Significant (P<0.05)
differences were observed on all blood profile parameters measured except the serum
creatinine. The serum glucose, urea nitrogen and total protein values ranged from 50.29
to 61.32 mg/dl, 5.73 to 8.64 mg/dl and 58.77 to 67.03 g/l, respectively. Values obtained
for serum glucose, urea nitrogen, serum creatinine and total protein fell within the normal
ranges of 50-100 mg/dl, 15-30 mg/dl, 1-2.7 mg/dl and 60-79 g/l, respectively for sheep.
In terms of economic benefit, the results revealed that cost of feed consumed per kg body
weight gain (497.76 ₦/kg) was lower and better in fattening rams fed diet containing 60:0
urea treated rice straw:gamba hay proportions. The study recommends that urea treatedxx
rice straw and gamba hay proportions of 60:0 UTRS:gamba hay could be used to replace
gamba hay as sole roughage diet for sheep feeding as sheep had higher weight gain in the
treated straw based diets compared to gamba hay based diet. The study further
recommends that small-holder farmers may adopt the treatment of rice straw with urea to
improve its nutritive value and reduce the cost of feed per kg body weight gain.1.0
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CHAPTER ONE
INTRODUCTION
Sheep are important part of the global agricultural economy and they play a major role in
many local economies (Weaver, 2005). Njidda and Kibon (2004) stated that sheep are
multipurpose animals, but they are primarily kept for the production of meat (mutton),
and they account for about 11% of the total meat supply in Nigeria. The authors further
stated that the inclusion of animals slaughtered in the rural areas outside the slaughter
houses would have made this figure higher. Afolayan (1996) reported that Yankasa sheep
is very popular among sheep farmers, most especially in northern Nigeria. Their high
productivity in terms of growth performance and prolificacy are paramount to the farmer
(Akpa et al., 2006). Inadequate and poor quality of feed, especially during the long dry
season is one of the major factors militating against livestock production in Nigeria. The
seasonality of feed supply in northern Nigeria has affected animal production adversely
(FDLPCS, 1992).
According to Rumirez-Orduna et al. (2005), due to high cost, most smallholder livestock
farmers cannot afford to supplement the diet of their animals with expensive feed
ingredients. Production of livestock and their productivity are far below the population’s
requirement for animal protein. This under-production and low productivity are attributed
mainly to inadequate year-round availability of feed and water, coupled with poor
management (Abbey et al., 2001). In the Savannah zone of Nigeria the basal diets of
most ruminants in the dry season is based on crop residues and dry standing grasses, and
most of these feed resources are imbalanced in nutritional value and vary from year to
year (Zemmelink, 1999).2
The natural rangeland serves as the major sources of forages for ruminants in Nigeria.
Rangeland forages, however, decline in both quality and quantity during the dry season,
resulting in low productivity of animals. Gamba (Andropogon gayanus) is a tropical grass
which is widely distributed throughout the savanna ecology of Nigeria and forms the bulk
of feed available to ruminants grazing on rangelands (Fitzhugh, 1978). Gamba grass is
usually established as permanent pasture in most commercial ranches or smallholder
farms. It can be cut as fresh feed or conserved as hay. The crude protein content of gamba
grass is moderate in young growth (7 – 10%) but declines rapidly with maturity (2 – 5%)
(Leeuw, 1979; Agishi, 1985). Alli-Balogun (2010) reported CP, NDF and ADF contents
of gamba hay as 3.76, 76.4 and 56.2%, respectively.
Rice straw, like other cereal crop residues is a potential source of energy for ruminants.
However, its potential as an energy source is limited because it is high in dietary fibre
(>50%) and low in crude protein (2 – 7%) and mineral contents (0.02 – 0.16%) (Sundstol
and Owen, 1984; Jung et al., 1993). One way in which, the low nutritive value of rice
straws could be improved, is through treatment with urea. In feeding trial strategies for
improving milk production by Ehoche (2002), urea treatment of crop residues is
acknowledged to improve nutritional value of crop residues and other fibrous by-products
and reduce feed cost and wastages with practical application at the smallholder level in
developing countries. The author further stated that in the tropics, cereal crop residues
such as maize, sorghum, millet stover and rice straw were produced in large quantities
and could be used as ruminant livestock feeds. Akande (2001) reported that in Nigeria,
rice is cultivated in virtually all agro-ecological zones and the residue (straw) can beJustification
Utilization of crop residues as feed has been the subject of intense research and
development worldwide since the mid1970s but there appears little effort has resulted in
greater utilization of crop residues in developing countries (Owen and Jayasuriya, 1989.
Kalio et al. (2013) reported that in Nigeria, millions of tons of crop by-products are
generated every year in our rural communities as unavoidable crop by products or
residues. Akande (2001) reported that in Nigeria, rice is cultivated in virtually all agro-
ecological zones. There is a tendency that paddy rice will be more available in future
through the recent Presidential initiative on rice production in Nigeria which is aimed at
encouraging local rice production in order to reduce over-dependence of the country on
imported rice (James, 2011) which means increase in rice straw output in the country.
Due to lack of adequate disposal facilities, most of the rice straw generated from rice
farming in Nigeria are left in the fields to be partially grazed by large ruminants only
without small ruminants benefitting as rice straw is inefficiently utilized by them because
3
obtained or purchased at relatively cheap or free of charge from all rice farms. According
to FAO (2012), Nigeria is the second largest producer of rice in Africa after Egypt and
the largest in West Africa. FAO (2013) reported that Nigeria production of paddy rice
was estimated at 4,700,000 tonnes. This gives rise to increase in rice straw output in the
country which could be harnessed for ruminant livestock feeding. It was also reported by
Parnich (1983) that, information on the utilization of rice straw in the diets of sheep is
scanty. The use of rice straws could help improve ruminant livestock production, if its
nutritive value is enhanced.