Strategies for improving productivity of Small Ruminants in Tanzania

Transcription

1 Strtegies for improving productivity of Smll Ruminnts in Tnzni Philosophie Doctor (PhD) Thesis John Godfrey Sfri Deprtment of Animl nd Aquculturl Sciences Norwegin University of Life Sciences Ås, 2010 Thesis numer 2010:52 ISSN ISBN

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3 Tle of Contents Acknowledgments... iii Astrct... v List of Ppers... vii Arevitions... viii 1.0 Introduction Ojectives of the study Mterils nd methods Min results Sesonlity, chnges in qulity of feed resources nd niml performnce Nutritionl flushing, seson of kidding nd reproductive chrcteristics of SEA gots Utiliztion of low qulity feeds in production of RM sheep nd SEA gots Feed intke nd growth performnce Slughter chrcteristics, crcss nd non crcss composition Met qulity chrcteristics ph nd temperture chnges Ageing, cooking loss nd met tenderness Generl discussion Sesonlity, chnges in qulity of feed resources nd niml performnce Nutritionl flushing, seson of kidding nd reproductive chrcteristics of SEA gots Utiliztion of low qulity feeds in production of RM sheep nd SEA gots Feed intke nd growth performnce Slughter chrcteristics, crcss nd non crcss composition Met qulity chrcteristics ph nd temperture chnges Ageing, cooking loss nd met tenderness Conclusions Future perspectives Ppers I-V i

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5 To my fmily ii

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7 Acknowledgments In the first plce, it is n honor for me to express my sincerest grtitude to my supervisor Dr. Lrs Olv Eik of the Norwegin University of Life Sciences (UMB). I ttriute the level of my Msters degree to his encourgement nd effort nd without him this thesis, too, would not hve een written. My co-supervisors Dr. Tormod Ådnøy of UMB, Professors George C. Kifro nd Luis A. Mteng of Sokoine University of Agriculture (SUA), gve useful guidnce with gret interest. I thnk you for offering much dvice nd insight. It is plesure to thnk Dr. Dniel E. Mushi of SUA who without fil supported me with ptience throughout my work, nd I thnk him for his receptive nd criticl comments. Professors Mrth Ulvund of the Norwegin School of Veterinry Science, Elikir. N. Kimit, Germn. H. Lswi, Vedsto. R.M. Muhikmele of SUA, Assistnt Prof. Mgne Mo of UMB nd Dr. Roert Mx of SUA re ll thnked for their technicl dvice. I wish to express pprecition to the Deprtment of Animl nd Aquculturl Sciences of UMB nd the memers of stff for providing the est lerning environment. I m most thnkful to the dministrtion of the Institute of Rurl Development Plnning (IRDP) nd in prticulr, Rector Constntine Lifuliro, Dr. D.B. Seyig nd T.R.K Mdendemi for their support in pursuit of my studies. They mde ville their support in numer of wys. I m lso grteful to Sokoine University of Agriculture through PANTIL project 020, the Hydom Luthern Church nd the Muldw frm in prticulr for the vitl support t vrious stges of this work. I extend my grtitude to the dministrtion of Awss College, Ethiopi nd the University of Fort Hre, Alice-South Afric for hosting me for short courses. At the University of Fort Hre, I ws ttched to three progrmmes; the School of Agriculture nd Agriusiness, Rurl Enterprise Advncement Progrmme nd studies on Africn Ecology under the ledership of the office of Den Fculty of Science nd Agriculture. Dr Voster Muchenje, Professors Peter Lent nd M. Chimonyo were directly involved. My visit to these institutions hs een gret lerning experience. The Smll Ruminnt reserch tem with its memers from the Deprtments of Animl Science nd Production, Veterinry Prsitology nd Veterinry Microiology of SUA is cknowledged for every support including provision for vrious fcilities during my reserch period. My respectful grtitude is to the lte Professor Amy Med-Mchng u who s iii

8 Professor nd mother inspired me gret del, my her soul rest in pece. Professors Edith E. Ndemnisho, Ayu A. Kssuku nd A.E. Kimmo nd mny others re thnked for their support nd encourgement. In the vrious lortory works, the ssistnce y technicins Lekki Kindm, Gideli Mfui, Dominic Alute, Mrgreth Kiody Mwn nd Gitn Mlekel is very much cknowleged. The technicl supports y Angello Mwilw in conducting the trnsect surveys to ctlog the ville plnt species t the Muldw frm is highly pprecited. I m delighted to cknowledge the id of Ann Sho, Innocent Thoms, Willim Hoz, Hji Ahmdi, Zkri Ally, Rju Omri nd Mohmed Hi in vrious stges of dt collection. I m very much grteful to mny friends t SUA, IRDP, UMB nd elsewhere. Drs. Ajeu Nurfet nd Etn Deel, formerly the PhD students t IHA nd now with Awss College, Devot Mwse, Aster Aee, Ismil Sulemn, Mulurhn Gremikel nd other fellow PhD students, you were friendly nd cheerful group of fellow students, for whom I will live to cherish the finest moments we hve hd in cdemics nd eyond. During my second yer of study, I hd frctures in my leg, hve often hd to seek for help nd mny countless individuls were there to ssist. To you ll, I thnk you wrmly, nd I consider you to hve een lessing. To ll of those who supported me in ny respect during my study period, I owe my deepest grtitude. The Norwegin Stte Eduction Lon Fund, Lånekssen nd the Progrmme for Agriculturl nd Nturl Resources Trnsformtion for Improved Livelihoods (PANTIL) project hve funded my studies. John sfri Ås, Norwy Septemer, 2010 iv

9 Astrct This thesis presents three res of emphsis, ll relted to feeds, feeding nd performnce of smll ruminnts. The first re (Pper I) focuses on sesonlity nd its effect on chemicl composition of forge species most preferred y SEA gots, grzing ehviour nd performnce of gots s ssessed in the riny (Ferury-My), mid dry (July-August) nd lte dry sesons (Octoer-Novemer). Evlution of these forges showed mrked decline in qulity s the seson chnged from riny to dry. The crude protein (CP) nd energy content of ll forges decresed while the neutrl detergent fire content incresed. The decline in feed qulity vried with forge clss. Unlike fors nd rowses, the men CP of grsses, for exmple, declined elow the criticl mintennce level for gots from the end of the riny seson through lte dry seson. Minerl concentrtions vried mong species nd forge clsses nd were ll low in phosphorous level. Chnges in seson were clerly ssocited with shifts in diet selection, grzing nd non grzing ctivities. Wheres herceous vegettion ws the min diet in the riny seson, rowses nd fors were importnt dietry sources in the dry seson. Oservtion on grzing ctivities nd performnce of gots in the sme study showed tht the proportion of time llocted for vrious ctivities vried with the chnging seson. For exmple, feeding time chnged from 0.57 (57 %) in the riny seson to 0.68 (68 %) in the lte dry seson. Body weight gins nd condition scores were highest in the middle of the dry seson while the lest performnce of these vriles ws recorded lte in the dry seson. The second re of this work (Pper II) presents n investigtion of the influence of pre-mting dietry supplementtion nd the seson of kidding on reproductive chrcteristics of SEA gots nd growth performnce of their off springs. The sesons were either erly dry (seson 1) or lte dry (seson 2). Results from three groups of 30 does ech sujected to 0, 200 or 400 g of concentrte diet/doe/dy for period of 60 dys prior to mting showed tht pre-mting dietry supplementtion improved (P<0.05) weight gins ut the reproductive performnce ws not improved. Doe weight chnges nd growth rtes of kids were ffected y the seson of kidding. Body weight chnges of does, pre-wening growth nd weight of kid wened per kg doe kidding nd the weight of kid wened per doe kidding were higher for kidding tking plce in seson 1 compred with tht in seson 2. Results suggest tht production efficiency of gots cn e v

10 incresed y restricting got reeding ctivities in Jnury-Mrch for kidding to tke plce erly in the dry seson (June-August). The third re (Ppers III, IV nd V) focused on growth performnce, crcss yield nd met qulity chrcteristics of smll ruminnts when supplemented with concentrte diets with either hy nd/or treted strws s sl diets. In Ppers III nd IV, 32 sheep nd gots were sujected to either d liitum untreted whet strw (UTS), whet strw treted with ure nd lime (TS), strw nd d liitum hy (UTSH) or TS nd d liitum hy (TSH). In ddition, ech niml received 220 g of concentrte diet/dy (on s fed sis) for 84 dys. Tretment of strw incresed (P<0.05) dry mtter intke (42.3 vs g/kgw.75 /dy), energy intke (4.6 vs. 3.7 MJ ME/dy) nd the verge dily gin (40.7 vs g) of sheep. The corresponding vlues for gots were (41.7 vs g/kgw.75 /dy), (4.55 vs MJ ME/dy) nd (16.9 vs. 8.1 g). Animls on TS lso produced hevier (P<0.05) crcsses with superior conformtion thn nimls on UTS. Results lso showed tht muscles from gots were less tender compred with those from sheep. In the finl study (Pper V), 23 cstrted SEA gots were used in 90-dy experiment. These gots were divided into four groups tht were fed either d liitum concentrte llownce (T100), 66 % of d liitum concentrte llownce (T66), 33 % of d liitum llownce (T33) or no concentrte (T0). For ech niml, grss hy ws offered d liitum t 20 % refusl rte. Dily ody weight gin for T100 gots ws 31 g nd 14 g higher (P<0.05) thn tht of T33 nd T66 gots, respectively. Hot nd cold crcss weights for oth T100 nd T66 gots were 3 kg hevier (P<0.05) thn tht of T0 gots. Results in Ppers III nd IV showed tht temperture decline in got crcsses proceeded t lower rte thn the decline in sheep crcsses nd tht the effect of diet on ph vlues ws not significnt (P>0.05). On the other hnd, got met hd slightly higher ph oth t 45 min PM nd 24 h PM thn sheep met. Post-mortem geing of sheep met improved (P<0.001) tenderness especilly fter 9 dys of geing. The Wrner- Brtzler sher force vlue of m. longissimus dorsi ged for 9 dys ws 20 % lower thn tht ged for 0 dy. However, geing of got met up to 9 dys PM hd no effect (P>0.05) on tenderness. Overll, results showed potentil for incresed productivity in smll ruminnts through improved nutrition nd proper timing of mting periods. Where chrcteristics of met qulity were ssessed, there were limited effects of dietry tretments on such chrcteristics. vi

11 List of Ppers I. Sesonl vrition in chemicl composition of ntive forges, grzing ehviour nd some lood metolites of Smll Est Africn gots in semi rid re of Tnzni. Mnuscript sumitted to Animl Feed Science nd Technology. II. III. IV. Influence of flushing nd seson of kidding on reproductive chrcteristics of Smll Est Africn does nd growth performnce of their progeny in semi rid re of Tnzni (Mnuscript). Growth, crcss yield nd met qulity ttriutes of Red Msi sheep fed whet strw-sed diets. Tropicl Animl Helth nd Production.doi10.007/s Growth, crcss nd met qulity chrcteristics of Smll Est Africn gots fed strw-sed diets. Livestock Science doi:1016/j.livsci V. Effects of concentrte supplementtion on crcss nd met qulity ttriutes of feedlot finished Smll Est Africn gots. Livestock Science 125, vii

12 Arevitions ADF ADG ADL BCS BW CCW CP DM DMI EBW EDTA FCR FLW GLM HCW IVOMD LD (0d) LD (6d) LD (9d) LL ME RM Phu PM SAS SEA TDMI TP WBSF Acid detergent fire Averge dily gin Acid detergent lignin Body condition score Body weight Cold crcss weight Crude protein Dry mtter Dry mtter intke Empty ody weight Ethylenediminetetrcetic cid Feed conversion rtio Finl live weight Generl liner model Hot crcss weight In vitro orgnic mtter digestiility m. longissimus dorsi ged for 0 dy m. longissimus dorsi ged for 6 dys m. longissimus dorsi ged for 9 dys Leg length Metolizle energy Red Msi Ultimte ph Post-mortem Sttisticl nlysis system Smll Est Africn Totl dry mtter intke Totl protein Wrner-Brtzler sher force viii

13 1.0 Introduction In the tropics, smll ruminnts re n importnt susistence mode of production contriuting sustntilly to the livelihoods of frmers through supply of wide rnge of products nd services. These include niml protein, income nd non conventionl utilities such s mnure, sset, security, employment genertion, frm integrtion nd vrious socil culturl nd religious functions (Degen, 2007; Hddd nd Oeidt, 2007; Ben Slem nd Smith, 2008). Brodly, the production system within which these nimls re rised is generlly chrcterized y low inputlow output, nd incresed production is invrily ssocited with n increse in livestock numers rther thn production efficiency. Consequently, production levels re often lower thn the economic optimum nd technicl mximum (Kosgey nd Okeyo, 2007). This system is lso ssocited with low off tke rtes (Armruster nd Peters, 1993; Pecock nd Shermn, 2010) prtly due to lck of mrketle nimls, poor niml condition or lck of willingness to sell those few in good conditions or ll of the ove. Poor condition of nimls especilly in the dry seson could lso e one of the resons for reluctnce of frmers to sell their nimls s they would receive low income. Unlike mrket-oriented commercil frmers, susistence livestock producers follow rod production ojectives tht re driven more y their immedite susistence needs rther thn demnds of mrket, nd the products re often mintined s stock for lter use (Aylew et l., 2003). Further, the production system of these nimls relies on cerel y-products like strws nd nturl pstures e.g. stnding hy which mke up the ulk of the feed. The totl mount nd qulity of these feed resources vry cross sesons nd gro-ecologicl zones depending on the mounts, distriution nd reliility of rinfll (Devendr nd Sevill, 2001; Angss nd O, 2007; Boone nd Wng, 2007). In dry res nd prticulrly during the drier months, these feeds re lrgely deficient in nitrogen nd high in lignocelluloses. The low qulity nd sesonl nture of forge supply together with low intke y nimls nd the poor digestiility of forges re fctors tht contriute to the low productivity of these nimls (Ngw et l., 2000). This is reflected clerly in low growth rte, low reproductive efficiency, delys in ttining slughter weight nd low nnul met yield (Hry, 2004; Mpiye et l., 2009; Mushi et l., 2009). In ddition, loss of ody weight (BW) nd condition s result of sesonl shortges nd low 1

14 qulity feeds is common phenomenon (O, 2001; Butt, 2010), nd such events often compromise reproduction, crcss yield nd met qulity (Dzi et l., 2003; Muchenje et l., 2009). Bsed on the spect of reproduction, evidence from literture nd prcticl experiences suggest tht, esides its direct effect on reproduction, nutrition modertes the effects of other fctors including genetic potentil nd physicl environment on reproductive performnce (Smith nd Akinmijo, 2000). Poor nutrition will not only reduce performnce elow genetic potentil ut lso excerte detrimentl environmentl effects. In ddition, nutritionl fctors perhps more thn ll others re more redily to mnipulte for positive outcomes, nd in the light of the sme spect of reproduction, gots in the tropics re known for their ility to reed throughout the yer. However, the impct of this nturl ility on productivity is compromised y restricted feed supplies in certin periods of the yer which my fil to support, for exmple, higher demnds of nutrients during lte pregnncy nd lcttion. The present work included investigtions on pproprite period for which reeding ctivities of smll ruminnts would improve flock productivity. In Tnzni, the livestock sector provides out 5.9 % of the Ntionl Gross Domestic Product (MLD, 2006). This contriution is low considering the lrge numers of livestock resources in the country which include 18.8 million cttle; 13.1 million gots nd 3.6 million sheep (MAFS, 2002). The met industry hs generlly not een le to meet the domestic demnd for met which results in importtion of lrge mount of chilled nd frozen met into the country ech yer (WHO/AFRO, 2009). One of the min resons is the production of low qulity crcss nd met in the country. For exmple, ccording to FAOSTAT (2009) dt, sed on 2008 sttistics, got nd sheep crcsses in Tnzni weigh less thn 13 kg. In the interntionl met mrket, such crcsses re generlly considered to e of poor morphology nd would e systemticlly penlized for their size (Russo et l., 2003). Attempts to improve size nd weight of crcsses re therefore importnt spects of production of smll ruminnts tht need to e ddressed y the Tnzni met industry. 2

15 In respect of the met qulity in Tnzni, the suject hs received strong emphsis prticulrly during the lst few yers. This is, in prt, due to increse in demnd for qulity met s result of severl fctors including increse in the influx of tourists nd exptrites in vrious service sectors. In ddition, this rise in demnd is possily ssocited with the increse in the segment of ffluent consumers in the country who serch for qulity met. Experience from other countries shows tht for consumers who re lredy wre nd concerned with helth issues, qulity is one of the mjor fctors tht determine their cceptility nd choice of met (Arsenos et l., 2002; Grunert et l., 2004). The met industry in Tnzni, therefore, needs to develop strtegies tht spn the entire met production chin tht must ssure consumers of high qulity met s it works to increse the shre of mrketle met nd met products. The term met qulity covers inherent properties of met decisive for the suitility of the met for eting, further processing nd storge including retil disply (Andersen et l., 2005). It includes ttriutes such s crcss composition nd conformtion, the eting qulity of the met, helth issues, environmentl impct nd conditions under which the met is produced (Mltin et l., 2003; Krystllis nd Arvnitoynnis, 2006). Numerous studies show tht met qulity is influenced y severl genetic fctors, such s reed (Teixeir et l., 2005; Esenug et l., 2009), slughter weight (Okeudo nd Moss, 2008; Peñ et l., 2009; Writthithm et l., 2010) nd sex (Sntos et l., 2007; Tejed et l., 2008; Rodríguez et l., 2008). Other fctors re environmentl, which include type nd level of feeding (Velsco et l., 2004; Cstro et l., 2005; Knnn et l., 2006), pre-slughter hndling, post-slughter crcss hndling nd the interctions of these fctors (Okeudo nd Moss, 2005; Vergr et l., 2005; Mirnd-de l Lm et l., 2009). Current work dels minly with crcss yield nd physico-chemicl properties of met from nimls rised on different type of diets. Genetic nd environmentl fctors cn hve effects on muscle/met structure, nd so too on met qulity ttriutes. For instnce, differences in collgen content nd soluility ccount for differences in tenderness mong niml reeds nd species (Tschirhrt-Hoelscher et l., 2006; Lepetit, 2008). Vrious studies (e.g. Kdim et l., 2006; Ferguson nd Wrner, 2008; Muchenje et l., 2009) hve lso reported significnt influence of pre-slughter hndling on met qulity chrcteristics prticulrly initil nd ultimte ph (phu), tenderness, wter-holding cpcity nd 3

16 colour. All these spell the need for continued reserch efforts tht seek to optimize yield nd qulity of met, nd to estlish good control nd stndrdiztion of the post-slughter environment. Since production performnce of smll ruminnts is constrined y poor nutrition s noted erlier on, it is impertive tht nutritionl strtegies re identified in order to increse productivity in this sector. Prior to ny nutritionl intervention, however, it is importnt to verify the types nd levels of limiting nutrients cross sesons s sis to the ssessment of niml performnce in its entirety. Thus, investigtions herein referred to s study I were crried out to evlute sesonl vrition nd chemicl composition of widely used ntive forges, nd to ssess the reltionship with ody weight nd condition together with chnges in the levels of nutritionlly relted lood metolites. Grzing ehviour of the nimls involved ws lso oserved for the purpose of determining the effects of chnges in nutritionl levels in ntive forges on grzing pttern of nimls in much roder context; since the vrition in the feed resource nd in the niml requirements cuses selective forging (Skrpe et l., 2007). The study involved testing the hypotheses tht gots rowse from feeds providing the highest levels of nutrients, tht sesonl vrition in nutritive vlues of feeds elicits forging shifts in fvour of the most nutritive feeds of the seson nd tht chnges in nutritive vlues of feeds impct iochemicl indictors in the lood s well s niml performnce. Considertions on the role of nutrition on reproduction, growth performnce, crcss yield nd met qulity lso prompted investigtions on the effect nutritionl flushing nd the kidding seson on reproductive performnce (Study II). The hypothesis tested ws tht kidding fter the long rins improves performnce of SEA gots nd tht supplementry feeding during pek-dry seson is needed if gots re to ttin high conception rte. Two other similr studies involving utiliztion of whet strw sed diets using Red Msi (RM) sheep (Study III) nd Smll Est Africn (SEA) gots (Study IV) were lso crried out. The ckground to these studies reltes to the fct tht in spite of the nutritionl importnce of cerel strws for livestock, these feed resources re generlly of poor feeding vlues s digestile energy, crude protein (CP) nd minerl content re ll low eside their physicl chrcteristics which limit intke nd digestion. On the other hnd, ppliction of chemicl tretment is known to upgrde the qulity of such 4

17 feeds. Tretment with chemicls such s lklis lters the chrcteristics of strws nd renders cell wll constitution more vulnerle to microil ttck in the rumen while dding nitrogen to the feed nd therey incresing feeding vlue, prticulrly digestiility nd intke potentil (Sundstøl, 1988; Zerini nd Thoms, 2003; Chen et l., 2008). In studies III nd IV the following hypotheses were tested (1) feeding upgrded whet strw improves growth performnce of sheep nd gots (2) ddition of hy to upgrded whet strw improves growth performnce of sheep nd gots nd (3) sed on hypotheses 1 nd 2, such effects improve crcss chrcteristics nd met qulity chrcteristics. The fifth nd finl prt of this work (study V) involved testing the effects of concentrte supplementtion on crcss nd met qulity of SEA gots. Here, gots were sujected to four levels of concentrte supplementtion which were denoted s T100, T66, T33 nd T0 for d liitum concentrte llownce (370 gdm/dy), 66 % of d liitum concentrte llownce, 33 % of d liitum concentrte llownce nd no concentrte supplementtion, respectively. The sis for this experiment ws founded on the fct tht use of low qulity forges lone my not support the desired level of niml performnce (Goodwin et l., 2004; Ben Slem nd Smith, 2008; Mornd-Fehr, 2005). Thus, testing vrious levels of supplementtion nd estlishing the optiml level ws required. In ddition, much of the reserch crried out in reltion to the use of low qulity sl roughges such s hy, stover nd strws (e.g. Tuen et l., 1991; Aee et l., 2004; Berhne nd Eik, 2006; Runz et l., 2007; Nurfet et l., 2009) hs not relted the suject with evlutions of met qulity chrcteristics. Overll, current reserch on nutrition extends from response in reproduction nd growth performnce to crcss nd met qulity chrcteristics of SEA gots nd RM sheep. The dt provide se-line informtion which my e useful for future reserch on smll stock nd met industry in the country. 5

18 2.0 Ojectives of the study To evlute the nutritive vlue of grzed ntive forges nd its impliction on some lood metolites nd grzing ehviour of SEA gots under free-rnging grzing conditions (Study I) To investigte the effects of pre-mting supplementry feeding nd the seson of kidding on reproductive chrcteristics, weight chnges of SEA does nd growth performnce of their off springs (Study II) To evlute the effects of feeding treted whet strw lone or in comintion with grss hy on growth performnce, crcss chrcteristics, non-crcss yield nd met qulity chrcteristics of RM sheep nd SEA gots (Studies III nd IV) To evlute the effects of different levels of concentrte diet on growth performnce, crcss nd met qulity of SEA gots (Study V) 6

19 3.0 Mterils nd methods Study I ws conducted to evlute the chemicl composition, digestiility nd utiliztion of the most preferred forge species in the diet of gots grzing/rowsing in semi-rid re of Tnzni. Grsses, fors nd rowses were collected during three sesons (riny: Ferury-My, mid dry: July-August nd lte dry: Octoer-Novemer). During these sesons, the grzing ehviours of sixteen non-pregnnt, non-lctting SEA does (25±1.2 kg BW) were oserved in ddition to the ssessment of chnges in ody weight, conditions scores, worm counts nd nutritionlly relted lood metolites. The ctivities recorded during grzing hours were: consumption of forge (grsses, fors or rowses), idling, wlking, stnding + ruminting, lying + ruminting, plying nd scrtching/self grooming. In Study II, the effects of supplementry diet (flushing) nd seson of kidding either erly dry (seson 1) or lte dry (seson 2) on reproductive chrcteristics of SEA does nd growth performnce of their progeny were ssessed for two successive yers (Novemer Decemer 2009). Ninety grzing does were divided into three groups of 30 does ech, which were lnced for ge, prity nd weight. The first group (control gots) ws not flushed while the remining two groups were supplemented with 200 or 400 g of concentrte diet /doe/dy for 60 dys efore mting. Does were then exposed to sexully ctive ucks in the months of Jnury through June 2008 nd 2009 nd monitored for the live-weight chnges, BCS nd reproductive chrcteristics such s fertility rte, prolificcy nd fecundity. In ddition, dt otined were nlysed for the effects of type of irth (single or twin), prity of the doe (<3, 3-5 nd >5) nd the irth type x doe prity interctions on growth performnce of kids. In studies III nd IV, thirty two cstrted RM sheep (12.7 kg BW) nd 32 cstrted SEA gots (13.8 kg BW), ged months were used in n 84-dy feeding experiment to evlute the potentil of using treted whet strw sed diets on growth rte nd yields of crcss nd noncrcss components s well s the met qulity chrcteristics of sheep nd gots. For ech species, nimls were locked y weight into four similr groups nd then rndomly llotted into four dietry tretments with eight nimls per tretment. The dietry tretments were either d liitum mount of untreted whet strw (UTS), treted whet strw (TS), untreted whet strw 7

20 with hy (UTSH) or treted whet strw with hy (TSH). Ech experimentl niml lso received 220 g/dy (on s fed sis) of concentrte diet composed of mize rn (70 %), sunflower seedcke (28 %) nd minerl mix (2 %). In study V, effects of supplementing SEA gots with different levels of concentrte diet on crcss nd met qulity were ssessed using 23 nimls (14.5 months old; 20.1 kg ody weight). The levels of concentrte diet were d liitum (T100), 66% of d liitum concentrte llownce (T66), 33% of d liitum (T33) nd no concentrte (T0). The experiment lsted for 90 dys. 8

21 Fig 1. Loction of the study res 9

22 4.0 Min results 4.1 Sesonlity, chnges in qulity of feed resources nd niml performnce The CP nd energy content of ll forges decresed with dvncing seson (Figures 2 nd 3) while NDF content incresed (Pper I, Tles 1, 2 nd 3). Crude protein content in rowses nd fors ws higher thn tht of grsses. The CP content rnged from 24.4 to 191.0, 45.7 to nd 97.5 to g/kg DM for grsses, fors nd rowses, respectively. Unlike grsses for which men CP vlues declined elow the criticl mintennce requirement level for gots from the end of the riny seson through lte dry seson, the opposite ws the cse for rowses nd to some extent fors. The content of neutrl detergent fire (NDF) nd cid detergent fire (ADF) rnged from to nd to (grsses), to nd to (fors), nd to nd to g/kg DM (rowses), respectively. Fig 2. Trends in crude protein (CP) (g/kg DM) of ntive grsses, fors nd rowses hrvested t Muldw In vitro orgnic mtter digestiility (IVOMD) coefficients nd predicted metolizle energy (ME) density were in the rnge of 28.7 to 61.3 g/kg DM nd 4.6 to 9.8 MJ/kg DM for grsses, 47.6 to 76.2 g/kg DM nd 6.4 to 12.2 MJ/kg DM for fors nd 22.7 to 69.6 g/kg DM nd 3.6 to 10

23 11.1 MJ/kg DM for rowses, respectively. Minerl concentrtions vried mong species nd were ll low in phosphorous level. Most plnts were rich in C. With exception of fors nd to some extent grss species, rowses were deficient in Zn while Cu ws only deficient in grsses. Fig 3. Trends in metolizle energy (ME) (MJ/kg DM) of ntive grsses, fors nd rowses hrvested in Muldw Comprisons of the grzing ehviour of gots in different sesons (Pper I, Tle 4) clerly indicted forging shifts in terms of types of diets selected nd chnges in grzing nd non grzing ctivities. Diet for the riny seson ws minly composed of herceous vegettion ut more rowses nd fors were consumed with dvncing dry seson. The proportion of time llocted to feeding chnged from 0.57 in the riny seson to 0.68 in the lte dry seson. Menwhile, the time spent idling decresed from (riny seson) to (lte dry seson). In ddition to the vritions in forging ctivities y sesons, there were differences in ody weight nd conditions together with nutritionlly relted lood metolites. Body weight gins nd condition scores were highest during erly dry seson while the lest performnce of the sme ws recorded during lte dry seson. Serum totl protein nd ure concentrtions were lso low during lte dry seson which coincided with low protein levels in the forge. 11

24 4.2 Nutritionl flushing, seson of kidding nd reproductive chrcteristics of SEA gots Results presented in Pper II shows tht dietry supplementtion improved (P<0.05) weight gins with the highest record in T400 group. However, supplementry feeding during pek dry seson does not seem to e necessry for locl gots to conceive especilly when gots re rised on lightly grzed rngelnd. Period of mting/kidding ws found to hve profound effects on weight chnges of does nd kids. The reltive weight increses of does during gesttion, the live weight increse of kids from week 4 to 12, the weight of kid wened per kg doe kidding nd the weight of kid wened per doe kidding were ll higher in seson 1 compred with those in seson 2. Also, the proportion of loss in weight of does from kidding to wening ws lower in seson 1 (6.1 %) thn tht in seson 2 (8.9 %). Thus, restricting got reeding ctivities in Jnury-Mrch for kidding to tke plce during erly dry seson (June-August) would improve productivity of gots in semi-rid res of Tnzni. 4.3 Utiliztion of low qulity feeds in production of RM sheep nd SEA gots This section summrizes results of three Ppers sed on studies III, IV nd V. Comprisons re mde prticulrly for studies III nd IV in which sheep nd gots were rised on the sme diets nd to less extent, on met qulity chrcteristics in studies III, IV nd V Feed intke nd growth performnce Results in Ppers III nd IV show tht for oth sheep nd gots, diet ffected (P<0.001) feed intke nd ody weight (BW) gin. Tretment of whet strw with ure nd CO improved (P<0.05) feed intke nd BW gin of the experimentl nimls. Hy hd positive effect on totl DMI for gots on UTS only (Pper IV, Tle 2). Totl feed nd DM intke s percentge of BW of sheep nd gots were higher in diets contining treted whet strw (TS, TSH) thn in diets sed on untreted whet strw (UTS, UTSH). There were differences in totl feed intke etween species. The totl DM intke for gots ws 9 % lower thn tht of sheep. When intke of DM ws expressed in metolic ody weight, the vlue for gots ws 5 % lower thn tht of sheep. The T100, T66 nd T33 gots consumed 370, 280 nd 140 g DM/dy of concentrtes, 12

25 respectively. However, the totl dry mtter intke of these gots were similr (P>0.05) nd higher (P<0.05) thn tht of T0 gots (Pper V, Tle 2). Compred to sheep, the performnce of gots in terms of BW gin nd feed conversion rtio ws poor (Pper III, Tle 2; Pper IV, Tle 2). The verge dily gin vried from 8.1 to 26.8 g for gots nd 23.1 to 47.8 g for sheep, depending on the diet on offer. It is intriguing to note tht the BW gin of nimls fed TS ws nerly twofold higher thn tht of nimls on UTS. Overll, sheep grew t 20 g/dy higher thn gots leding to 1.6 kg greter totl weight gin in fvour of sheep. The overll men finl ody weight for sheep ws 10 % higher thn tht of gots. In study V, the dily weight gins incresed with n increse in concentrte llownce while T0 gots lost weight t rte of 23.6 g/dy (Pper V, Tle 2) Slughter chrcteristics, crcss nd non crcss composition Diet cused significnt differences on the men finl ody weight (FBW), shrunk ody weight (SBW), empty ody weight (EBW) nd commercil dressing percentge, eing higher for nimls fed treted strw thn for those fed untreted strw sed diets. Diets lso ffected (P<0.05) hot crcss weight (HCW) in sheep nd gots with the min difference occurring etween TS nd UTS. Hot crcsses from TS nd TSH were out 18 % hevier (P<0.05) compred with those from UTS (Pper III, Tle 4; Pper IV, Tle 6). Addition of hy to TS nd UTS did not increse crcss weight. Gots hd lower gut fill thn sheep (16.5 % vs %) nd higher (P<0.01) commercil dressing percentge thn sheep (44.2 % vs %). Comprison of the dressing percentge etween gots in study IV nd study V shows higher vlues for the ltter. Muscles of nimls on treted strw sed diets were hevier (P<0.05) compred with those on untreted strw sed diets (Pper III, Tle 5; Pper IV, Tle 7). Diets, however, hd no (P> 0.05) effect on dissectile muscle contents of got nd sheep when expressed s percentge crcss weight. The percentge of ft tissue in the crcsses from gots nd sheep fed TS, TSH nd UTSH were similr (P>0.05) nd higher (P<0.05) thn tht in crcsses from UTS. Dietry tretments hd no effect (P>0.05) on the weight of one tissue. When expressed s percentge of 13

26 crcss weight, the proportions of ones were highest in gots nd sheep mintined on UTS. There were no (P>0.05) dietry effects on the muscle: one rtio. Crcss ftness score ws significntly ffected y type of feed. Crcsses from TS hd superior (P<0.05) conformtion nd ftness scores over those from UTS. Men conformtion scores were O for gots nd O - for sheep sed on 15-point EUROP scle. Neither strw tretment nor hy inclusion influenced the liner crcss mesurements. On the other hnd, gots on T0 hd the lest crcss conformtion nd ftness scores (Pper V, Tle 3). Except for the hind lim width, liner crcss mesurements nd indices were not influenced y diet (Pper III, Tle 4; Pper IV, Tle 6; Pper V, Tle 3). Totl non - crcss yield s the proportion of shrunk ody weight in gots (32 %) ws sustntil nd similr with tht in sheep (33.3 %). With the exception of the hert ft, ll other internl ft depots (omentl, mesenteric, pelvic nd kidney) s well s totl non-crcss ft depot were in higher proportion for gots thn for sheep Met qulity chrcteristics ph nd temperture chnges The effect of diet on ph vlues ws not significnt (P>0.05) in studies III, IV nd V. However, niml species influenced the pttern of ph decline wherey got met hd slightly higher ph thn sheep met oth t 45 min PM nd 24 h PM. The verge phu for got met ws 6.2 fter completion of glycolysis (24 h PM) while tht of sheep ws 5.7. Temperture decline in got crcsses proceeded t lower rte thn the decline in sheep crcsses. Comprison of the proximte composition etween got nd sheep met indicted tht most of the nutritionl indices were little influenced y species under these feeding conditions Ageing, cooking loss nd met tenderness Post-mortem geing of sheep met improved (P<0.001) tenderness especilly fter 9 dys of geing. The WBSF vlue of LD 9d ws 20 % lower thn tht of LD 0d while post-mortem geing of got met hd no effect (P>0.05) on tenderness. In Pper V, however, geing of got 14

27 met for 6 nd 9 dys resulted in similr reduction of WBSF nd these vlues were higher thn tht of met ged for zero dy. Except for m. triceps rchii nd m. gluteoiceps, diet hd no effect on the cooking loss (CL) of most of the individul muscles studied (Pper III, Tle 7; Pper IV, Tle 9). In study V, diet hd no effect (P>0.05) on CL of ny of the muscles studied. A wide vrition, however, ws oserved in CL etween muscles. In oth sheep nd gots, the CL for m. semimemrnosus for exmple, ws out twice s gret s tht from the m. rectus dominis (Pper III, Tle 7; Pper IV, Tle 9; Pper V, Tle 5). On the other hnd, m. longissimus dorsi ged for 0 nd 9 dys, m. gluteoiceps, m. psos mjor nd m. semimemrnosus in sheep exhiited higher CL thn similr muscles in gots, nd so too ws the tendency in other muscles. With the exception of m. longissimus dorsi (0d) nd m. semitendinosus, WBSF vlues were not ffected y diet ut wide vritions etween species ws noted. Muscles from sheep hd lower men WBSF vlues compred to vlues otined in got muscles. For exmple, if mens of WBSF vlues for m. gluteoiceps nd m. vstus lterlis re pooled in ll diets nd compred, the vlues of the respective muscles re 30 % nd 26 % higher in gots thn the corresponding vlues in sheep. 15

28 5.0 Generl discussion 5.1 Sesonlity, chnges in qulity of feed resources nd niml performnce The decline in nutritive vlue found in ll forge clsses, leit with vrying degree is result of dvncing mturity. Illustrtions of these were given in Figures 2 nd 3. Of the fctors influencing nutritive vlues such s plnt species, vriety, growing conditions, plnt frction nd stge of plnt mturity t smpling (Moreir et l., 2004; Arzni et l., 2006; Chves et l., 2006; Suym et l., 2007), mturity influences forge nutritive vlue more thn ny other single fctor (Hssen et l., 2007). This is minly due to increse in the proportions of structurl crohydrtes such s cellulose, hemicelluloses nd lignin nd decrese in CP (Buxton nd Fles, 2004; Kozloski et l., 2005). Such forges hve impired rtes of cellulose nd hemicelluloses digestion (Beever nd Mould, 2000), nd often constrin intke s the niml cn et no more thn 1.2 % of its ody weight s NDF (Mertens, 1992). The oserved persistence in higher levels of nitrogen in leguminous shrus nd tree species reltive to other forge clsses is well documented in other studies (Tinton, 1999; Ahmed nd Elhg, 2003; Runz et l., 2007). For exmple, Yyneshet et l. (2009) reported the CP contents (g/kg DM) of to (long rins), to (dry period) nd to (short rins) in leves of five rowse species from Tigry Region of Northern Ethiopi. Two importnt spects explin the scenrio of high nutrient content throughout the sesons. First, is the ility of these plnts to fix tmospheric nitrogen vi the symiotic reltionship with soil cteri (Ammr et l., 2004). Second, most of these plnts hve deep rooting system tht llows them to tke up wter nd other nutrients from deep lyers of soils (Dulormne et l., 2004). Bsed on the CP content, most of the rowse species evluted in the present study could e regrded s medium to high qulity forges. The lowest CP content recorded for O. kirkii (97.5 g/kgdm) in mid dry seson is still higher thn the minimum threshold level (80 g/kgdm), which would limit intke of tropicl forges (Minson, 1980). As depicted in Figures 2 nd 3, tropicl grsses re chrcterized y rpid fll in nutritive vlue with dvncing dry seson, feture lso widely reported in literture (e.g. Bwire et l., 2004; Kozloski et l., 2005; Berhne nd Eik, 2006; Mhieu et l., 2008). Grsses in the tropics re lso known to contin 5 to 11 16

29 MJ/kgDM of ME nd 20 to 200g/kgDM of CP (Wilkins, 2000), nd ecuse of these fetures, they my not provide nutrients dequtely during certin months of the yer. Psture exmined in the present study ws predominntly composed of the grss species nd ws expected to hve low level of CP (i.e. <80 g/kgdm) for most of the yer, unless it consisted of pprecile proportions of fors nd trees, which s indicted in Fig 2 or in Tles 2 nd 3 (Pper I) contined high levels of CP. As such, dditionl supply of nitrogen rich forges s shown in report y Runz et l. (2007) would help to meet the requirement for rumen degrdle protein nd improve niml performnce. In the cse of minerls, the low levels of phosphorous noted is feture prevlent in the tropics (Tinton, 1999; Rmirez-Orduñ et l., 2005). The concentrtion of individul minerls in tropicl forges vries widely depending on soil, plnt species nd mngement fctors (McDowell, 2003). Such vritions re lso seson dependent (Henlein nd Rmirez, 2007; Hssen et l., 2007; Khn et l., 2010). This is ecuse the vilility of nutrients in the soil nd the cpcity of the root system to sor them re ffected y wether ptterns (Vn Soest, 1994). Pek levels of minerls occur usully when growth is most ctive. Therefter, the levels egin to decline. Most of the minerls studied in the present work were clerly t the lowest levels during lte dry seson. Bsed on chemicl composition, species hving low fire nd high CP levels such s A. xnthophloe, O. kirkii, B. stepi, L. cpensis, Sorghum spp nd C. nlemfuensis could e employed to improve the qulity of stnding hy. In ddition, these forge species nd other dicotyledonous species hve potentil dvntge of enhncing the concentrtion of minerls e.g. S. rundo which contined reltively high levels of P. However, evlution of nt-qulity fctors such s solule phenolic nd condensed tnnin compounds for such plnts is needed. In view of feed selection, forging preference for grsses exhiited during the riny seson (Pper I) could e explined y the fct tht during this seson, grsses re more succulent, less corse nd high in protein content. It hs een demonstrted tht gots nd other grzing ungultes show high preference for forges with such ttriutes, so tht grsses t this stge of growth, offer etter choices thn rowses (Odo et l., 2001; Goodwin et l., 2004; Codron et l., 2007). On the other hnd, low preference for grsses in the dry seson is most likely ttriuted to 17

30 incresed concentrtions of NDF nd lignin which re known for their inhiitory effects on intke nd digestion in grzing nimls (Moore nd Jung, 2001; Csler nd Jung, 2006). The importnce of fors nd rowse especilly during the dry seson is suggested y preferentil rowsing in their fvour s plnt species from these two clsses often hd higher levels of nutrients (crude protein, energy nd minerls). Importntly, rowse species serve s reserves tht ensure continued supply of nutrients to grzing nimls in the dry seson when iomss of stnding grss is low nd deficient in nutrients for mintennce or production requirements. The shifts in choices of forge nd time llocted for eting such s those oserved in the present study supports the view tht when nimls detect swrd heterogeneity, their forging wlks re not rndom ut structured to efficiently utilize the swrd structure in such mnner s to mximize intke of nutrients (Soder et l., 2007). This therefore, underlines the importnce of diversity of plnt species in grzing environments, the ide encompssing wide rnge of plnt species nd the reltive undnce of species present (Mgurrn, 2004). The outlined sesonl chnges in qulity of forges (Pper I, Tles 1, 2 nd 3) were reflected in iochemicl indictors in the lood nd most likely contriuted to the chnges in ody weight nd condition in gots (Pper I, Tle 5). 5.2 Nutritionl flushing, seson of kidding nd reproductive chrcteristics of SEA gots Tht flushing did not improve reproductive performnce of grzing SEA does is contrry to the findings of Kiker et l. (2007) nd Blche et l. (2008) who reported improved conception rtes nd generlly the reproductive performnce of flushed femles over those tht were not flushed. The present results re, however, similr to those of Acero-Cmelo et l. (2008) who found tht inclusion of concentrte diet did not improve reproductive performnce in met gots. Explntion for such differences is most likely the vritions of nimls used. For instnce, erlier works hve indicted tendency for nimls in good condition not to respond to flushing (Coop, 1966; Hrt, 2008). In their evlution of the effect of BCS on ovrin ctivity, Dpoz et l., (1995) recommended flushing for femles with BCS elow 2.5. In the present study, the verge condition score of does t reeding ws not fr from the optiml rnge of 3.0 to 3.5 (Sphr, 2004; Roinson et l., 2006), nd this is likely to hve prtly resulted in poor response to 18

31 flushing. In ddition, the smll numer (90) of gots used in this study might hve contriuted to the filure to depict significnt differences in reproductive performnce of gots under different levels of dietry supplementtion. Another importnt spect regrding interction of nutrition nd reproduction is the level of energy nd protein on offer nd the timing nd durtion of flushing. A review y Smith nd Stewrt (1990), for exmple, showed tht feeding high-energy rtion for less thn one oestrous cycle does not increse ovultion rte ut high-protein supplementtion incresed ovultion in s fewer s six dys. Generlly, oth erly (i.e. grzing ckground) nd, to lesser extent, recent nutritionl history (pre-mting flushing tretments) could ffect ody weight nd condition t mting nd hence the reproductive performnce (Molle et l., 1995; El-Hg et l., 1998; Ock et l., 2006). More work with respect to nutrition nd reproduction of locl gots in Tnzni is therefore needed in order to estlish circumstnces under which frmers cn improve production efficiency of gots tking into ccount the multiple fctors ffecting reproduction under grzing conditions. Depressed increse in gesttionl weight mong does tht kidded in seson 2 (lte dry) reltive to their counterprts kidding in seson 1(erly dry) is proly due to insufficient nutrients ville for the former group where, for exmple, ville CP from fors nd grsses ws found to e t the level elow mintennce requirements (Fig 2). Eqully, energy levels in seson 2 were t the lowest point (Fig 3). When the dietry supply of nutrients is indequte, incresed nutritionl requirements re met y moilizing ody reserves. Consequently, gots like other domestic species re sensitive to nutritionl stress during pregnncy especilly under extensive mngement conditions (Blche et l., 2008), nd therefore, ccelerted loss in ody weight of dms is expected. Reserch work from other studies indicte tht severe feed deprivtion during vrying stges of pregnncy seems to excerte live weight losses nd increse the risk of reproductive wstge due to ortion, retrdtion of fetl growth, reduced irth weight nd incresed neontl deth rte (Melldo et l., 2004). Periods of severe nutritionl stress pre-prtum re lso likely to ffect levels of milk production, further incresing the likelihood of neontl losses nd depressed growth performnce (Hry nd Schwrtz, 2002). An ssocited feture of the post-prtum dietry effects is tht where kidding/lcttion period does not coincide with the dequte nutritionl supply, post-prtum oestrus cyclicity is impired (Roinson et l., 2006). In respect of the weight chnges of does post-prtum oserved in the 19

32 current work, ssumption is mde tht does kidding in seson 2 were less le to withstnd the incresed physiologicl stress ssocited with milk production s compred with those kidding in seson 1. Thus, in the context of nutritionlly sensitive periods in got production s well s other species in the frming system within which they re kept, it is necessry tht reeding ctivities considers the vilility of feed resources for such periods. And in the cse of the present work, reeding should tke plce etween Jnury nd Mrch. 5.3 Utiliztion of low qulity feeds in production of RM sheep nd SEA gots Feed intke nd growth performnce The higher DM intke recorded for sheep compred with gots is supported y findings of Sormunen-Cristin nd Kngsmki (2000). A study y Hddd nd Oeidt (2007) lso showed tht lms consumed 218 nd 216 % more DM nd OM compred to kids, respectively nd tht the CP, NDF nd ADF intkes showed similr pttern. Differences in intke nd digestion etween sheep nd gots pper to depend on nutritionl qulity of the diet or feed compred nd the feeding systems generlly. Vn et l. (2007) reported tht when stll fed d liitum, gots hve lower ility to digest low qulity feeds thn sheep ut when given ccess to grzing, gots select etter prts of plnts nd hve the sme or etter ility to digest such feeds thn sheep. Such illustrtions were lso presented y Slem et l. (2006) where gots consumed 3.9 % more DM thn sheep per kg BW.75, nd tht their ility to digest tree foliges s the sl diet ws higher y 8 %. Tissernd et l. (1991) nlysed the possile mechnisms for which good digestion of poor forge in gots could e explined; conclusion ws reched tht gots tend to retin nutrients longer in the digestive trct, hve higher concentrtion of cellulolytic cteri in the rumen nd re more efficient in recycling lood ure. The DM intkes otined in studies III nd IV re comprle to 43.4 g/kg 0.75 for sheep nd 42.6 g/kg 0.75 for gots fed whet strw s sole diet (El-Meccwi et l., 2009) while Shoo et l. (2000) in Indi reported s high s 49.5 g/kg 0.75 intke in rms of Muzffrngri reed fed upgrded whet strw. These vritions could e due to the differences in qulity of strws 20

33 which in literture indictions re tht whet strws cover wide rnge of chemicl composition (Luschgne et l., 2000; Ryn et l., 2008; Mzzeng et l., 2009). The difference in genotypes of whet which is lso relted to vritions in the proportion of lef nd stem components of the strw produced, ffect digestiility nd men retention time of digest in the reticulorumen (Hdjigeorgiou et l., 2003). This lone my explin why chemicl tretment does not hve the effect of ringing different cultivrs/genotypes to similr digestiility levels s reported y Hi et l. (1998). Other fctors ffecting intke include physiologicl stte of niml nd the level nd frequency of feeding (Goetsch et l., 2004). Incresed CP content in TS in the present study my explin the increse in DMI oserved in sheep nd gots fed TS sed diets. Approximtely 25 % increse in DMI due to ure tretment is common ut vrile, sometimes even etween experimentl periods of the sme tril (Shoo et l., 2000). Feed intke in oth niml species in the present work ws within the expected rnge of 2 to 5 % of the ody weight per dy for finishing sheep nd gots (NRC, 1985). Results from the present study indicte potentils for treted strw to sustin smll ruminnts during the dry seson. In study V, finishing of SEA gots t 66 % (244 gdm/dy) of d liitum concentrte intke seemed to e the optiml mount to improve weight gins nd crcss ftness. In reference to growth performnce nd s noted erlier, poor growth nd feed conversion rtio in gots could e ssocited with stll feeding system. Stll feeding limits feed selection nd ppers to e more unfvourle for gots thn for sheep. Lower growth rte in gots compred to sheep could lso e due to species differences in growth potentils. As for the unsupplemented gots (T0) in study V, the loss in weight in this group, implies tht hy lone is not le to provide sufficient nutrients for mintennce Slughter chrcteristics, crcss nd non crcss composition Feeding regimen is known to ffect crcss composition of frm nimls prticulrly the ft content when there is vrition in energy concentrtion nd intke of diets (Gruszecki et l., 2001; Mhgou et l., 2005; Atth et l., 2006). Results presented in Pper III for exmple, show tht the dietry energy intkes were 4.61, 4.65, 3.48 nd 4.00 MJ, ME/dy for sheep on TS, TSH, UTS nd UTSH respectively, nd to gret extent, this ccounts for the oserved vritions in ft content in the crcsses. Gots hd higher totl non crcss ft thn sheep. The explntion is more likely to e tht gots entered fttening phse erlier thn sheep s mture 21