ABSTRACT
A feeding trial lasting 90 days was conducted using 28 Yankasa weaner rams with an average weight of 14.96 ± 1.10 kg (5-6 months old) to investigate effect of sequence and
feeding interval of concentrate supplement (CS) and roughage on performance. The animals were randomly assigned to four treatments (T1: CS fed 1 h prior to feeding grass hay; T2: CS fed 2 h prior to feeding grass hay; T3: grass hay fed 1 h before feeding CS; and T4: grass hay fed 2 h before feeding CS) using a 2×2 factorial arrangement in a randomized complete block design (RCBD). The animals were fed Wooly finger grass (Digitaria smutsii Stent) hay and CS at the rate of 2.4% and 1.6% of body weight, respectively, and offered water ad libitum. Blood collection was done every 4 wk before feeding and 4 h after second feeding. Rumen fluid was collected before feeding and 3 h after second feeding during the last week of feeding trial. Thereafter metabolism trial was conducted with 20 of the rams. Animals in treatment 2 had greater dry matter intake (P < 0.05) than animals in treatment 1, but statistically similar in dry matter intake to those in treatments 3 and 4. The total weight change of treatment 4 animals was significantly (P < 0.05) higher than those of treatment 1 animals, but statistically similar to weight change of treatment 2 and 3 animals. Differences in average daily gain (ADG) among treatments were not significant (P > 0.05). Total volatile fatty acids and pH values of the rumen of the rams 3 h post-feeding were affected (P < 0.05) by the interval of feeding. Blood creatinine levels 4 h post-feeding were only significantly (P < 0.05) affected by interval of feeding grass hay and CS. Apparent digestibility of dry matter (DM) and organic matter (OM) was higher in treatment 4 animals, although no significant (P > 0.05) differences among treatments. Nitrogen intake and retention were not significantly (P > 0.05) different among treatments. It is concluded that, even though, feed intake and growth rate of Yankasa rams were not markedly affected by the sequence (of feeding) as much as interval of feeding CS and grass hay, the rams in treatment 4 had better feed efficiency and nutrient digestibility for better
feed utilization and improved performance. Yankasa rams can be fed grass hay 2 h before feeding concentrate supplement.
TABLE OF CONTENTS
Title Page
Title page..…………………………………………………………………………… ii
Declaration…………………………………………………………………………… iii
Certification………………………………………………………………………….. iv
Dedication…………………………………………………………………………… v
Acknowledgement…………………………………………………………………… vi
Abstract……………………………………………………………………………… viii
Table of Contents…………………………………………………………………… x
List of Figures……………………………………………………………………….. xv
List of Tables………………………………………………………………………… xvi
Abbreviations………………………………………………………………………… xvii
CHAPTER ONE
INTRODUCTION…………………………………………………………………… 1
CHAPTER TWO
REVIEW OF LITERATURE……………………………………………………… 5
2.1 IMPORTANCE OF SMALL RUMINANTS IN NIGERIA…………………. 5
2.1.1 Breeds of Sheep, Population and Distribution in Nigeria…………………… 7
2.1.2 Factors Affecting Productivity of Small Ruminants in Nigeria…………….. 9
2.2 FEED RESOURCES FOR SMALL RUMINANTS………………………….. 11
2.2.1 Cereals, Legumes and Fodder Crops………………………………………… 11
2.2.2 Sugar Beet and Citrus Pulps………………………………………………….. 11
2.2.3 Lignocellulosic Agricultural By-products……………………………………. 12
2.2.4 Wheat Middling………………………………………………………………… 13
2.3 FORAGE RESOURCES OF NIGERIA……………………………………….. 15
2.3.1 Limitations of Forage Feed Resources………………………………………… 17
2.4 FEED SUPPLEMENTS…………………………………………………………………………… 19
2.4.1 Concentrate Supplements (Energy, protein, vitamins and minerals)……….. 21
2.4.2 Supplementary Feeds and its Combination for Efficient Use of Roughages… 24
2.5 RUMEN ENVIRONMENT AND NUTRIENT SYNCHRONY………..…….. 28
2.6 FEEDING REGIMES IN SMALL RUMINANT PRODUCTION…………… 32
2.7 RESPONSE OF RUMINANTS TO SEQUENCE AND FEEDING INTERVAL OF SUPPLEMENTS AND ROUGHAGES…………………………………………………. 34
CHAPTER THREE
MATERIALS AND METHODS…………………………………………………………………….. 38
3.1 LOCATION OF THE STUDY…………………………………………………. 38
3.2 ANIMALS AND EXPERIMENTAL DESIGN………………………………. 38
3.3 EXPERIMENTAL DIETS AND MANAGEMENT OF ANIMALS……….. 39
3.4 MEASUREMENT OF BLOOD AND RUMEN METABOLITES………… 42
3.5 METABOLISM TRIAL……………………………………………………… 42
3.5.1 Animals, Design and Experimental Procedure……………………………… 42
3.6 CHEMICAL ANALYSIS……………………………………………………… 43
3.7 CALCULATIONS AND STATISTICAL ANALYSES……………………. 43
CHAPTER FOUR
RESULTS………………………………………………………………………… 45
4.1 FEEDING TRIAL…………………………………………………………… 45
4.1.1 Composition of Diet………………………………………………………… 45
4.1.2 Voluntary Feed Intake……………………………………………………… 45
4.1.3 Liveweight Changes………………………………………………………… 49
4.1.4 Feed Efficiency……………………………………………………………… 53
4.1.5 Rumen Metabolites……………………………………………………… 53
4.1.6 Blood Metabolites………………………………………………………… 56
4.2 METABOLISM TRIAL…………………………………………………… 60
4.2.1 Nutrient Intake…………………………………………………………… 60
4.2.2 Apparent Nutrient Digestibility………………………………………… 62
4.2.3 Nitrogen Balance………………………………………………………… 64
CHAPTER FIVE
DISCUSSION…………………………………………………………………… 67
5.1 FEEDING TRIAL…………………………………………………………… 67
5.1.1 Dry Matter Intake…………………………………………………………… 67
5.1.2 Liveweight Changes………………………………………………………….. 68
5.1.3 Feed Efficiency………………………………………………………………… 69
5.1.4 Rumen Metabolites…………………………………………………………… 70
5.1.4.1 Rumen VFAs Concentration ………………………………………………… 70
5.1.4.2 Rumen Ammonia Nitrogen …………………………………………………. 71
5.1.4.3 Rumen pH…………………………………………………………………… 71
5.1.5 Blood Metabolites…………………………………………………………….. 72
5.1.5.1 Blood Glucose…………………………………………………………….. 72
5.1.5.2 Blood Urea Nitrogen……………………………………………………… 73
5.1.5.3 Blood Serum Total Protein………………………………………………… 74
5.1.5.4 Blood Creatinine…………………………………………………………… 74
5.2 METABOLISM TRIAL……………………………………………………… 75
5.2.1 Nutrient Intake……………………………………………………………… 75
5.2.2 Apparent Nutrient Digestibility…………………………………………… 76
5.2.3 Nitrogen Balance…………………………………………………………….. 76
CHAPTER SIX
6.1 SUMMARY…………………………………………………………………… 78
6.2 CONCLUSION AND RECOMMENDATION………………………………………. 78
6.3 CONTRIBUTIONS TO KNOWLEDGE……………………………………. 79
REFERENCES……………………………………………………………………. 80
CHAPTER ONE
INTRODUCTION Sheep and goats are domestic animals that have been associating with humans for a very long time. In traditional setting, they serve as means of ready cash and a reserve against economic and agricultural production hardship (Hamito, 2008). They play a significant role in the food chain and overall livelihoods of rural households, where they are largely the property of women and their children (Lebbie, 2004). They are good producers of meat for human consumption. The short gestation interval of sheep and goats and the absence of religious bias against their meat (Ozung et al., 2011) are among the reasons why they are kept by peoples of various cultures, religions and races. In the developed countries where consumers are conscious of fat intake, a situation which results into cardio-vascular diseases, goat meat (chevon) with comparatively low amount of intramuscular fat are preferred to beef and/or mutton. It has been reported that there is now a niche market for chevon in US (Luginbuhl, 2000; Coffey, 2006; Okpebholo and Kahan, 2007).
Productivity of small ruminants in many tropical areas is often poor because they are subjected to various kinds of diseases, feeding and housing management techniques. Several survey reports (Devendra and Burns, 1983; Okorie and Sanda, 1992; Ademosun, 1994; Aliyu et al., 2005; Shiawoya and Tsado, 2011) indicated that small holder farmers that own over 70% of the livestock population in sub-Saharan Africa offer their stocks little or no supplementary feed. Yet because of low nutrient quality, pasture alone and more specifically tropical grasses cannot provide growing animals sufficient amount of energy intake to attain appropriate growth rate for higher slaughter weight and dressing percentage (Humphreys, 1991). Several works had shown that
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young animals raised on forages alone had lower daily gains, dressing percentage and carcass quality than those supplemented with concentrate (Warmington and Kirton 1990; Johnson and McGowan 1998; Kosum et al., 2003; Johson et al., 2005). Concentrate feeds promote rapid growth of sheep and cattle (McDonald et al.,1996), increase propionate production and reduce ruminal methane production, thereby lowering energy losses and contributing to higher overall efficiency of utilization of dietary energy for body weight gain (Mandebvu and Galbraith, 1999). According to Mtenga and Kitalyi (1990) increase in meat output resulting from concentrate supplementation can improve access to animal protein and income to households in the traditional sector. With respect to milk production, Kolver et al. (1998) opined that supplementation with concentrates is a viable option to enhance milk production in lactating dairy cows under grazing conditions. Increase in level of dietary concentrate was observed to cause increase in milk production in ewes (Avondo et al., 1995; Zervas et al., 1999) and Red Sokoto goats (Otaru, 2009). However, high levels of concentrate feeding can cause low ruminal pH (Mould et al., 1983; Carro et al., 2000), which can decrease forage degradability (Mould et al., 1983; Allen, 1997) and induce clinical ruminal acidosis. The appropriate ratio of concentrate to roughage to be fed to ruminants had been studied (Zervas et al., 1999). A ratio of 40:60% concentrate to hay had been recommended (Liu et al., 2005). Concentrate supplements by nature are more easily degraded than roughages. Consequently, concentrate supplements fed before feeding roughage degrade rapidly and lower the rumen pH before the buffering effect of roughage fermentation, which occurs afterwards, sets in.
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According to Smith (1992), feed constraints currently limiting small ruminant production and productivity in humid West Africa were, to a large extent, due to a non-strategic utilization and combination of available feed resources, to develop production feeding system, rather than absolute quantitative and qualitative shortages. It is a common practice that farmers, under semi-intensive system in the forest belt of humid West Africa, offer feed supplements to their animals first thing in the morning before turning them out to graze fibrous grasses all day. However, results of rumen degradability studies suggested that this system should be the other way round, with the rapidly degraded feeds fed late in the afternoon and at night, to better synchronize the release of the energy and nitrogen they contain with those of the less rapidly degraded grasses. There is a need to verify this premise on-farm (Smith, 1992).
Feeding of concentrate supplements subsequent to feeding roughage had been suggested to enhance higher intake of roughages, and increase productivity of animals (Robinson, 1989; Beauchemin, 1992). Nevertheless, work by Robinson (1994) showed that changing the sequence of feeding supplemental grain relative to forage-based mixed ration did not improve or modify the productivity of primiparous cows. Many of the experiments conducted to investigate the influence of changing the sequence of feeding concentrate supplements and roughages on the performance of ruminants either fed supplement 1 h (Robinson, 1994; Carro, 1994) or less than 1 h (Morita and Nishino, 1993; Zeyner et al., 2004) before or after feeding the roughage. The time intervals were probably too short for effective degradation of basal ration; hence there is a need for extended time intervals. In addition, there is paucity of information on similar studies with our indigenous small ruminants using the compounded concentrate supplement.
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Therefore, this study was designed to evaluate the effects of changing the sequence of feeding concentrate supplement and grass hay on performance of Yankasa weaner rams. The objectives of this study were to:
i. Determine the appropriate time interval for feeding concentrate supplement relative to grass hay.
ii. Determine the effect of the sequence and feeding interval of concentrate supplement and grass hay on feed intake, digestibility of nutrients, and growth of Yankasa weaner rams.
HYPOTHESIS Ho: The sequence and interval of feeding concentrate supplement and grass hay will not have effect on intake and performance of Yankasa weaner rams. HA: The sequence and interval of feeding concentrate supplement and grass hay will have effect on intake and performance of Yankasa weaner rams.
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