Carcass Characteristics of Wad Rams Fed Ensiled Maize Forage and Mucuna Pruriens Foliage

Alabi, B. O.^1*, Ososanya, T. O.² & Akinduro, V. O.¹

¹Department of Animal Science, Osun State University, Osogbo, Nigeria
²Department of Animal Science, University of Ibadan, Ibadan, Oyo State, Nigeria

*Correspondence to: Dr. Alabi, B. O., Department of Animal Science, Osun State University, Osogbo, Nigeria.

Copyright © 2019 Dr. Alabi, B. O., et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Introduction
Sheep are believed to have evolved in the dry and mountainous regions of southwest and central Asia. Present day domesticated sheep were derived from strain of the wild animals in existence in southwest Asia some 8,000-10,000 years ago [1]. They can survive in many areas especially in the tropics where cattle would perform poorly and play a significant role in the economy and nutrition of rural and urban dwellers. In Nigeria where production of small ruminants is largely extensive, and fodder provision is erratic throughout the year, survivability of sheep has been low due to poor nutrition.

Generally, the feeding pattern of these WAD rams is a characteristic of the native husbandry practice whereby they scavenge for food to meet their daily nutrient requirement [2]. However, the feeding system for ruminants should be manipulated in such a way that the outputs such milk and meat would not be compromised [3]. Ensiling is one of the best techniques of preserving abundant forage materials, crop residues, agricultural and industrial by-products for use in times of scarcity [4].

Certain forage legumes appear as important component in the diets of sheep and goat to meet their nutrient requirement. Mucuna pruriens has been used as food and feed in a large number of countries where it has been introduced [5]. Where Mucuna pruriens is consumed by human, it is typically the beans that are consume, though in some areas immature pods and leaves have also been eaten [5]. For animal fed both bean and foliage, its potential as food and feed are affected by two opposing forces. On the positive side, by its relatively good seed and forage yield and beneficial composition of nutrients and minerals, and on the negative side, by its anti - nutritional components [5]. Maize forage on the other hands, particularly when it contains the stalks, leaves and ears is an energy feed for ruminants [6].

The production of sheep mutton (especially rams) is carried out in a wide range of environment using various different production systems throughout the world [7]. Meat from sheep accounts for approximately 18.0% of the total red meat production in Turkey [7]. The present meat production from West African dwarf rams is far from optimal. Therefore, there is the need to continue to research on the performance of West African dwarf rams on different regime using locally available feeding stuffs that can improve their performance. Feeding ensiled maize forage and Mucuna pruriens foliage to ruminants is believed to be a total mixed ration and can solve the problem of meat production. Therefore, the present study focused on the carcass characteristics of West African dwarf (WAD) rams fed ensiled Maize Forage (MF) and Mucuna pruriens foliage (MPF) was assessed.

Materials and Methods

Study Location
This study was done at the Crop Production Unit, Teaching and Research Farms, University of Ibadan, Small Ruminant Unit, Teaching and Research Farms, University of Ibadan and Department of Animal Science Lairage, University of Ibadan, Ibadan, Nigeria.

Planting of Mucuna and Maize
Two acres of land was used for the planting of Mucuna and maize seeds. The land was adequately ploughed twice, harrowed once and fenced before planting to prevent accidental grazing. The plot was divided into two equal dimensions of one acre each for separate planting of maize and Mucuna seeds. Seeds of both downy mildew/streak resistance (DMR-SR) yellow variety maize and Mucuna were purchased from International Institute of Tropical Agriculture, (IITA), Ibadan. Mucuna pruriens seeds were planted at 2 seeds per hole two weeks before the planting of DMR-SR yellow variety maize, which was planted at 2-3 seeds per hole. Weeding was done manually once at four weeks after planting during the growing period. Thinning was done on maize plot to 2 stands at 3 weeks after planting, while supplying of seeds was done on Mucuna pruriens plot at two weeks after planting.

Harvesting and Silage Making
Mucuna pruriens foliage was harvested at eight weeks after planting (onset of flowering) while maize was harvested at dough stage as maize forage (including maize stalks, leaves, immature cobs and tassels, excluding the roots) at six weeks after planting. Harvested Mucuna pruriens foliage and maize forage were chopped into 2-3cm pieces (for easy compaction) as recommended by [4]. Chopping of forages was done by using chopping machine fabricated for the purpose of silage production located at the dairy unit of Teaching and Research Farm, University of Ibadan, Nigeria [8]. Thereafter, the chopped materials were wilted under shade for 24 hours on polyethene sheets spread on concrete floor. That was followed by ensiling the maize forage and Mucuna pruriens foliage in different proportions to form four silage combinations (dietary treatments) as follow;

• T1 = 100% MF + 0% MPF
• T2 = 75% MF + 25% MPF
• T3 = 50% MF + 50% MPF
• T4 = 25% MF + 75% MPF

MF - Maize Forage
MPF - Mucuna pruriens Foliage

Experimental Silage Preparation
The silage was prepared in polythene bags in triplicates and compressed with piles of 70Kg of sand bags in 200litre containers for acceptability and growth studies. Fermentation was done for 21 days as recommended by [4].

Preparation of Pens
The animals’ pens were made of low walls of 1.90m (Height) by 7.10m by 13.94m in size. Each pen was about 1.83m long and 1.54m wide. The floor of the pen was made of concrete and the roof of the building that housed pens was made of corrugated iron sheets. The pens were washed thoroughly with detergent and were further disinfected with broad spectrum insecticide, acaricide and larvicide (Diazintol). The feeding and drinking troughs were washed and disinfected and the whole house was left to rest for two weeks before usage. Wood shavings were spread on the floor of the pens up to a depth of 5cm as bedding materials and also to enhance prompt removal of urine and faeces and were replaced fortnight.

Experimental Animals and Management
Twenty (20) post weaned West African dwarf rams with average initial body weight of 12±0.25Kg and 6-8months old were used for the experiment. They were purchased from Ikire in Osun State, Nigeria. On arrival, the WAD rams were given a prophylactic treatment which consisted of oxytetracyline long acting antibiotic (1ml/10Kg body weight of the animal) and vitamin B complex. They were also drenched with albendazole to control endo-parasites and treated for mange and other ecto-parasites using ivomec. During the acclimatization period for four weeks, rams were offered local diets from where they were purchased for the first two weeks and were introduced to the experimental diets for the remaining part of the acclimatization period. At the end of the adjustment period, the WAD rams were weighed and allotted to four dietary treatments on weight equalization basis such that the average initial weight per treatment was not statistically different. Silages were offered at 5% body weight. Fresh water and feed were served ad libitum each for the one hundred and five days (105 days) duration of the experiment. Salt licks were placed permanently in each pen. Weights of rams were taken on a weekly basis using weighing scale before the morning feeding.

Carcass Analysis
At the end of the 105 days growth study, twelve (12) rams were randomly selected by use of random number from the twenty (20) experimental WAD rams (3 rams per treatment) for carcass characteristics evaluation. Prior to slaughtering, the rams were starved but given water for sixteen (16) hours and then weighed and slaughtered.

Slaughter Procedure
The rams were restricted by holding down their limbs. The head was turned at an angle of about 90º such that the neck blood vessels were clearly displayed. The rams were slaughter by severing the jugular vein, carotid arteries, trachea and esophagus, using a sharp thin knife. The rams were removed at the Atlanta-occipital joint and the fore and hind feet at the carpal and tarsal joint respectively. The removal of the skin was initiated at the abdomen along the breast line. Immediately after skinning evisceration was carried out and the carcass components were weighed separately and expressed as percentage of slaughtered weight. The carcasses were then divided along the mid line and the left half carcasses were cut into prima cuts of shoulder, lions, shanks, brisket, rack, flank, hind leg and neck. The percentage compositions of the cuts were calculated as a proportion of the half carcasses weight. The cut were then dissected into lean, fat and bone.

Dressing Percentage

Rib Eye Area
Rib eye area of carcasses was measured following the procedure of [10]. This was done by tracing the outline of Logissimus dorsi muscle between the 12^th and 13^th ribs. The tracing was done on a sheet of Matte acetate paper (Tracing paper). The smooth side of the sheet was laid on the cut surface of the meat. Pressure was applied with the finger to make the structure visible and muscle outline was traced out with a soft fine Hb lead pencil. The actual area measurement was done using grid method [11]. Graph papers containing centimeter square boxes with each square (cm²) box sectioned into 0.1× 0.1cm2 were used. The acetate paper was placed on the graph and all 0.1cm² filled with Longisimus dorsi muscle structure visible on the paper were counted while those that will be less than half filled were ignored.

Experimental Design
The experimental design adopted was completely randomized design (C R D).

Data Analysis
Data obtained were subjected to analysis of variance (ANOVA) using the procedure of [12]. Statistically significant observed means were compared using LSD of the same package.

Results
Table 1 shows carcass characteristics of WAD rams fed ensiled maize forage and Mucuna pruriens foliage. There were significant (P<0.05) differences in body weight at slaughter (BWS), Hot carcass weight (HCW), dressing percentage (DP) and Rib eye area (REA) of slaughtered rams across the dietary treatments. BWS was significantly highest (22:28kg) for WAD rams on T2 (25% MF +75% MPF) and lowest (18.25kg) in rams on T4(25% MF + 75% MPF). The same trend, were observed for HCW and DP which ranged from 10.25kg (T4) to 14.26kg (T2) and 56.16% (T4) to 64.00% (T2), respectively. Also, REA was significantly highest (23.30) for rams on T2 and lowest (20.20) for rams on T4. However, no significant differences (p>0.05) were observed for the values of non- carcass components such as heads, feet, hearts, kidneys, lungs and livers of slaughtered rams across the dietary treatments.

a, b, c, d: - means along the row with different superscript differs significantly (P<0.05).
T1- %100 MF
T2 -75% MF + 25% MPF
T3 - 50% MF + 5% MPF
T4- 25% MF + 75% MPF
MF = Maize Forage
MPF = Mucuna pruriens foliage

Table 2 shows the proportion of carcass weight retail cut from WAD rams fed ensiled maize forage and Mucuna pruriens foliage. There were significant (p<0.05) differences in the value of percentage meat (%meat), percentage (%, bone) and meat to bone ratio of slaughtered WAD rams across the dietary treatments. Percentage meat was significantly highest (73.64%) for slaughtered WAD rams on T2 (75% MF + 25% MPF) followed by T3(50% MF + 50% MPF) with value of 72.63% and followed by rams on T1 (100% MF) with value of 69.22% while meat of WAD rams on T4 had the lowest value 69.20%. Percentage bone of slaughtered rams ranged from 21.02% for WAD rams on T3 (50% MF + 50 MPF) to 25.33% for WAD rams on T4 (25% MF + 75% MPF). The values of meat to bone ratio of slaughtered rams were 2.76, 3.50, 3.45 and 2.72 for WAD rams on T1 (100% MF), T2 (75% MF + 25% MPF), T3 (50% MF + 50% MPF) and T4 (25% MF +75% MPF) respectively. However, no significant (p>0.05) differences were recorded for neck weight, brisket and fat percentage of slaughtered WAD rams across the dietary treatments as they all have close range of values. Percentage of fat ranged from 5.47% for slaughtered rams on T4 (25% MF + 75% MPF) to 6.32% for the slaughtered rams on T1 (100% MF).

a, b, c: means along the same row with different superscript differs significantly (P< 0.05)
T1 -100% MF
T2- 75% MF + 25% MPF
T3 - 50% MF + 50% MPF
T4 - 25% MF +75% MPF
MF = Maize Forage
MPF = Mucuna pruriens foliage

Discussion
The HCW obtained in this study were within 11Kg reported by [11] as the average carcass weight of sheep slaughtered in Nigeria.

Several authors [13-15], noted that the effect of slaughter weight is associated with offal. The dressing percentage obtained in this study agreed with findings of other researchers [14-16] who reported a range in values from 47.60 to 53.20% but higher than ranged values (43.70 - 43.80) reported by [17] in goats with slaughter weight of about 13.90Kg. This shows that the dressing percentage was influenced by differences in daily gain and could be traced to the beneficial effect of inclusion level of maize forage and Mucuna pruriens foliage in the silage. [18] reported the dressing percentage of lambs fed finishing diets without sodium bicarbonate (NaHCO₃) and yeast to be 53.2%. The rib-eye area is an indication of meatiness. In the present study rams on T2 (75% MF: 25% MPF) silage were more meaty compared to rams on other dietary treatments. According to [19], rib eye area has a positive relationship with carcass cutabilty and percentages of retail cut. Leg muscle score and rib eye are the most useful indicators of muscling though not perfectly related. The rib eye area is the most useful and accurate indicator of total muscle and the only trait that can be objectively quantified in a practical manner in the live animal or carcass. The meat to bone radio obtained in the present study was in line with the value reported by [11]. The aim of production should be to produce animal of rapid growth, heavy carcass that will be blocky and thick, with minimum waste as bone, a maximum of muscle and, ideally, no waste fat at all, that is, there is no fat that will require removal by trimming [11].

There is an extent to which bone can be reduced [11] reported that as bone weight varies, least of the main carcass tissues (bone, muscle and fat), its relative amount is much greater with small dressing percentages than it is with high value. The fatter the animal becomes, the less will be bone content, expressed as a percentage of carcass weight. However, there is little merit in carcass with low percentage of bone, but with considerable quantity of the fat to be removed as fat trimmings. Besides, the production of muscle (protein synthesis), rather than fat, is the main purpose of production. It is less demanding of nutrients (that is, requires quantitatively less raw materials) than fat, which is such a high energy substance.

Conclusion
From the result of the experiment, it is concluded that maize forage and Mucuna pruriens foliage had been preserved successfully through ensiling as a dry season feed resource for ram production. Feeding maize forage and Mucuna pruriens foliage silage to WAD rams at 75% MF + 25% MPF produced carcass with better dressing percentage, optimum rib-eyes area and high meat to bone ratio.

Bibliography

1. FDLPCS. (1991). Federal Department of Livestock and Pest Control Services, Nigerian National Livestock Survey, 2, Abuja.
2. Daramola, J. O., Adeloye, A. A., Fatoba, T. A. & Soladoye, A. O. (2005). Haematological and biochemical parameters of West African Dwarf goats. Livestock Research for Rural Development, 17(8).
3. Rehn, S. and Espig, G. (1991). The cultivated plants of the tropics and sub - tropics (translated by G. McNamara & C. Ernsting). Verlay Josef Margraf, Germany. VIII +522 pages. Journal of Tropical Ecology, 8(1), 86.
4. t’ Mannethje, L. (1999). Introduction to the Conference on silage making in the tropics, In: L’t Mannetje, ed., Silage making in the tropics with particular emphasis on smallholders, FAO, Plant production and protection paper, 1161. Rome, 173-175.
5. Carsky, R. J. Tarawali, S. A., becker, M., Chikaye, D., Tian, G. & Sangiga, N. (1998). Bucuna-herbacerus cover legume with potential of multiople sues. Resource and crop management research monograph 25. International Institute of Tropical Agriculture, Ibadan, Nigeria, (p. 52).
6. Methu, J. N., Kiruiro, E. M. & Abate, A. N. (2006). Your feed shortage, use maize forage. Feedipedia. Animal Feed Resources Information System. KARI Resource Centre, Nairobi, Kenya.
7. Turkstat (2005). Turkish Statistical Institute.
8. Olorunnisomo, O. A. (2011). Silage characteristics and acceptability of elephant grass and cassava peel silage by ruminants in Southwest Nigeria. The 3rd International Conference on Sustainable Agriculture for Developing Countries (SAADC, 2011). July 26 - 29, 2011. Nakhon Ratchasima, Thailand. (pp. 201 – 207).
9. Aduku, A. O. and Olukosi, J. O. (1990). Rabbit management in the tropics: Production, processing, utilization, marketing, economics, practical training and future prospects. Nigeria Journal of Animal Production, 25, 34-40.
10. Kembi, S. O. and Okubanjo, A. O. (2002). Physicochemical and sensory properties of dehydrated beef patties containing soyabean product. Tropical Animal Production Investigation, (5), 137-148.
11. FAO (2005). FAOSTAT data. Food and Agriculture organization Rome.
12. SAS. (2003). Statistical Analysis Systems, User’ Guide, Version 8 ed., SAS Institute Inc. SAS Campus Drive Cary, North Carolina, USA.
13. Woodman, H. E. and Evan, R. E. (1974). The nutritive value of fodder cellulose when fed to ruminants and pigs. Agric Sci., XXXVII. 202-222.
14. Akgunduz, V., Onzoglu, A. I., Koyuncu, Filya, I. Deligogoglu, F. and Tuncel, E. (1994). Etel Koyun Irklri ile kivircik melezi kuzularm besi performansi ve karkas ozellikleri. Jouirnal of Lalahun livestock Research Institute, 34(3-4), 48-64.
15. Ogan, M. (2001). Sakiz x kivircikmelezi (F1) erkek kuzularin besin performansi ve karkas ozillikleri. Journal of Lalahan Livestock Research Institute, 41(1), 59-66.
16. Akeapinar, H. (1981). Akkaraman ve Kivircik Kukularm farkli kesim agirliklarinda bsi performansi ve karkas ozelliklerinin karsilastrilmas. Yearbook, Vol. 28, College of Agriculure, Ankara University, Ankara, Turkey. (pp. 112-129).
17. Rao, Kowale, B. N., and Verma, A. K. (2002). Effect of feeding water washed neem (Azadirachta indica) seed kernel cake in the quality, lipid profile and fatty acid composition of goat meat. Small Ruminant Research, 47(3), 213-219.
18. Kawas, J., Garcia - Castillo, R., Fimbres - Durazo, H. AND Garza - Cazares, F. (2007). Effects of Sodium bicarbonate and yeast on nutrient intake, digestibility and ruminal fermentation of light - weight lambs fed finishing diets. Small Ruminants Research, 67(2-3): 157-165.
19. Abdul-Aziz, G. M., El Shaer, H. M., fahmy, A. A., Shalaby, A. S., & El Gawad, A. M. (2001). Carcass quality of fattened sheep fed halophytic silage with non- conventional energy supplement. In Egypt option mediterranennes series. A. Seminaires Mediterraneens, (46), 35-43.