Made available in DSpace on 2014-06-11T19:32:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-22Bitstream added on 2014-06-13T21:05:20Z : No. of bitstreams: 1 souza_sf_dr_jabo.pdf: 545661 bytes, checksum: 5f5b21c5f337a4a6bfe8d55019cb730b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivou-se avaliar os impactos da restrição nutricional em cabritos machos castrados, fêmeas e machos não castrados da raça Saanen dos 05 aos 15 kg de peso corporal (PC). Foram utilizados 46 cabritos da raça Saanen (17 machos não castrados, 14 fêmeas e 15 machos castrados), submetidos a três diferentes níveis nutricionais (ad libitum, restrições de 25% e de 50%), sendo que os sob restrição tiveram a oferta diária de alimento baseada no consumo do ad libitum. Foram avaliados os parâmetros de desempenho, carcaça, composição corporal, perfil metabóliconutricional, hormônios tireoidianos, biometria, escore de condição corporal, morfometria óssea e densitometria mineral óssea. Todos os animais foram abatidos quando os ad libitum atingiram 15 kg de PC, realizando-se a avaliação dos componentes de carcaça (pesos de carcaça quente e de carcaça fria), dos não-componentes de carcaça (órgãos internos e depósitos de gordura) e da composição corporal. O perfil metabóliconutricional e hormônios tireoidianos foram determinados em dosagens séricas realizadas ao longo de nove semanas sucessivas. O sexo não exerceu efeito (P>0,05) sobre nenhum dos parâmetros avaliados. Os animais em aleitamento mostraram-se mais eficientes que no pós-desaleitamento. Os componentes de carcaça e de não carcaça foram afetados negativamente (P<0,05) pelas restrições, havendo redução (P<0,05) na deposição de tecido muscular e na composição corporal em gordura, assim como nos parâmetros de desempenho, biometria, escore de condição corporal, morfometria e densitometria mineral óssea. As estruturas ósseas internas foram mais afetadas que as externas, e quanto às densidades, nas epífises foram mais afetadas que na diáfise. Dos parâmetros séricos, apenas os de uréia, creatinina, colesterol e fósforo... / The objective was to assess the impact of nutritional restriction in castrated male, females and males not-castrated Saanen kid goats from 05 to 15 kg of body weight (BW). Was used 46 Saanen kid goats (17 not-castrated, 14 females and 15 castrated males), under three different nutrient levels (ad libitum, restriction of 25% and 50%), and the under restriction had the daily supply of food based on consumption of ad libitum. Was evaluated the performance parameters, carcass characteristics, body composition, nutritional-metabolic profile, thyroid hormones, biometrics, body condition score, bone morphometry and bone mineral density. All animals were slaughtered when the ad libitum reached 15 kg of BW, and where the assessment of carcass components (weight of hot and cold carcass), the non-carcass components (internal organs and fat deposits) and body composition. The nutritional-metabolic profile and thyroid hormones were determined in serum taken over nine consecutive weeks. Sex had no effect (P >0.05) on any of the parameters evaluated. Lactating animals were more efficient than the post-weaning. The components of carcass non-carcass components were negatively affected (P <0.05) by restrictions, with a decrease (P <0.05) in muscle tissue deposition and body composition in fat, the same way as parameters of performance, biometrics , body condition score, morphometry and bone mineral density. The internal bone structures were more affected than outside and on the densities in the epiphyses were more affected than in the diaphysis. Of serum parameters, only urea, creatinine, cholesterol and phosphorus were affected (P <0.05) of the restrictions. Was also negative (P <0.05) impact in concentrations of triiodothyronine hormone. Considering the results presented, can concluded that the restrictions have an impact under different parameters and with different intensities in Saanen kid goats in the early stages of growth

Orientador: Kleber Tomás de Resende / Banca: Renato Luis Furlan / Banca: Kênia Cardoso Bícego / Banca: Silvio Doria de Almeida Ribeiro / Banca: Juan Ramon Olalquiaga Perez / Resumo: Objetivou-se avaliar os impactos da restrição nutricional em cabritos machos castrados, fêmeas e machos não castrados da raça Saanen dos 05 aos 15 kg de peso corporal (PC). Foram utilizados 46 cabritos da raça Saanen (17 machos não castrados, 14 fêmeas e 15 machos castrados), submetidos a três diferentes níveis nutricionais (ad libitum, restrições de 25% e de 50%), sendo que os sob restrição tiveram a oferta diária de alimento baseada no consumo do ad libitum. Foram avaliados os parâmetros de desempenho, carcaça, composição corporal, perfil metabóliconutricional, hormônios tireoidianos, biometria, escore de condição corporal, morfometria óssea e densitometria mineral óssea. Todos os animais foram abatidos quando os ad libitum atingiram 15 kg de PC, realizando-se a avaliação dos componentes de carcaça (pesos de carcaça quente e de carcaça fria), dos não-componentes de carcaça (órgãos internos e depósitos de gordura) e da composição corporal. O perfil metabóliconutricional e hormônios tireoidianos foram determinados em dosagens séricas realizadas ao longo de nove semanas sucessivas. O sexo não exerceu efeito (P>0,05) sobre nenhum dos parâmetros avaliados. Os animais em aleitamento mostraram-se mais eficientes que no pós-desaleitamento. Os componentes de carcaça e de não carcaça foram afetados negativamente (P<0,05) pelas restrições, havendo redução (P<0,05) na deposição de tecido muscular e na composição corporal em gordura, assim como nos parâmetros de desempenho, biometria, escore de condição corporal, morfometria e densitometria mineral óssea. As estruturas ósseas internas foram mais afetadas que as externas, e quanto às densidades, nas epífises foram mais afetadas que na diáfise. Dos parâmetros séricos, apenas os de uréia, creatinina, colesterol e fósforo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective was to assess the impact of nutritional restriction in castrated male, females and males not-castrated Saanen kid goats from 05 to 15 kg of body weight (BW). Was used 46 Saanen kid goats (17 not-castrated, 14 females and 15 castrated males), under three different nutrient levels (ad libitum, restriction of 25% and 50%), and the under restriction had the daily supply of food based on consumption of ad libitum. Was evaluated the performance parameters, carcass characteristics, body composition, nutritional-metabolic profile, thyroid hormones, biometrics, body condition score, bone morphometry and bone mineral density. All animals were slaughtered when the ad libitum reached 15 kg of BW, and where the assessment of carcass components (weight of hot and cold carcass), the non-carcass components (internal organs and fat deposits) and body composition. The nutritional-metabolic profile and thyroid hormones were determined in serum taken over nine consecutive weeks. Sex had no effect (P >0.05) on any of the parameters evaluated. Lactating animals were more efficient than the post-weaning. The components of carcass non-carcass components were negatively affected (P <0.05) by restrictions, with a decrease (P <0.05) in muscle tissue deposition and body composition in fat, the same way as parameters of performance, biometrics , body condition score, morphometry and bone mineral density. The internal bone structures were more affected than outside and on the densities in the epiphyses were more affected than in the diaphysis. Of serum parameters, only urea, creatinine, cholesterol and phosphorus were affected (P <0.05) of the restrictions. Was also negative (P <0.05) impact in concentrations of triiodothyronine hormone. Considering the results presented, can concluded that the restrictions have an impact under different parameters and with different intensities in Saanen kid goats in the early stages of growth / Doutor

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: One of the reasons why meat supply does not meet human demand is that man has concentrated on utilising relatively few animal species as a source of meat. Development of unconventional livestock, such as goats, is advocated as a means of increasing global meat production and consumption. Although South Africa possesses large numbers of domestic ruminants, meat consumption has been limited mainly to sheep and cattle. Goats are used to a lesser extent. This is partly attributed to a general belief that goat meat is inferior to mutton and beef. Numerous contradictions regarding comparative goat and sheep growth, carcass characteristics and meat composition exist in literature. Concepts involved with most of the contradictions includes average daHy gain (ADG), dressing percentage, carcass weight distribution and organoleptic characteristics, especially tenderness, juiciness and flavour, particularly as pertaining to animals reared/grown under intensive/feedlot conditions. Therefore this project was undertaken to obtain more information on the growth, carcass and organoleptic characteristics, as well as meat chemical compositions of Boer goat (BG) kids in comparison with South African Mutton merino (MM) lambs, reared under feedlot conditions. Thirty-two BG kids and 32 MM lambs were used for this investigation. All the animals were castrated and weaned before entering the feedlot. Two pelleted diets (fed to 16 animals/species) with either a low (LE; 8.9 MJ/kg OM) or a high (HE, 10.9 MJ/kg OM) metabolisabie energy level were fed individually, ad lib for either 28 or 56 days. Feed and water intake, ADG and feed conversion efficiencies (FCE) were monitored. During the last week of the feeding trial, 12 BG kids and 12 MM lambs were used to evaluate the digestibility of the two diets. After either 28 or 56 days, the animals were slaughtered and the carcasses dissected into South African commercial cuts. The m. semimembranosus and 8-9-10-rib cut of each carcass was dissected for determination of chemical composition, drip loss, cooking loss, shear force values and colour measurement. The m. gracilis was dissected from the hind leg of the carcass and used for sensory evaluation. MM's had significantly higher AOG's than BG's (e.g. MMHE56: 0.281; BGHE56: 0.162 kg/day). Within a diet there was no difference (P>0.05) in FCE between BG's and MM's and only the MM's FCE differed between the LE and HE diet (e.g. BGLE28: 7.65; BGHE28: 6.37; MMLE28: 8.73; MMHE28: 5.56 kg feed/kg weight gain). BGLE digested dry matter (OM), crude protein (CP) and energy more efficiently and had a higher energy retention than MMLE. The two diets had the same ME-value for the goats, which confirms that goats perform equally well on a lower quality feed as their contemporaries on a higher quality feed. Neither species, nor diet affected nitrogen retention. The BG had a 49 % lower (P<0.01) water intake per kg weight gain than the MM on both the high and low energy diets. Both species had a lower (P<0.01) water intake on the high than on the low energy diet. Furthermore, the BG had a daily water intake of only 171 ml/kgo.75 compared to the 302 ml/kgo.75 of the MM. The weight of the liver, empty stomach, head and feet (as a percentage of empty body weight) were higher in goats than in sheep. The MM's had significantly heavier skins, probably due to wool growth. Both kidney fat and gastro-intestinal tract (GIT) fat increased with age. The animals slaughtered after 56 days in the feedlot had significantly longer and deeper carcasses than their contemporaries slaughtered after 28 days. Within a diet and slaughter age, the MM had significantly broader and deeper carcasses than the BG's. BG's had significantly less weight per unit carcass length, and thus more slender carcasses than MM's. Diet had no significant influence on the carcass weight distribution of the goats. However, MM's had heavier carcasses (LE: 19.87 vs. 15.28 kg; HE: 24.01 vs. 17.05 kg) and proportionally heavier ribs and buttocks than BG's. Neither diet nor slaughter age influenced the proximate analysis of the m. semimembranosus, but MM's had significantly lower moisture values than BG's. In the 8-9-10-rib cuts BG's had significantly more moisture and protein and lower fat and energy values than MM's. OM, fat and energy values increased with an increase in slaughter age in both species. BG's had significantly higher concentrations of 11 of the 18 measured essential amino acids in their 8-9- 10-rib cuts than the MM's. Gaat carcasses had higher Ca, K, Mg, Na and P-Ievels than sheep carcasses, regardless of the diet fed. There was a tendency for goat's m. semimembranosus to have a lower Fe-content than that of sheep. BG carcasses had a lower carcass cholesterol content than that of lamb (66.77 vs. 99.28 mg/100g, respectively). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1 n9) acid comprised the greatest proportions of fatty acids in both the m. semimembranosus and 8-9-10-rib cut for both species. On a LE-diet there was no significant difference between the saturated fatty acid (SFA) to unsaturated fatty acid (UFA) ratio of goat meat and lamb. However, on the HEdiet, lamb had a significantly higher SFA:UFA ratio than chevon (m. semimembranosus: 0.842 vs. 0.689; 8-9-10-rib cut: 1.407 vs. 0.892). Organoleptically, a difference was noted between chevon and lamb. Each has a specific species flavour, which was not influenced by energy level of the diet. BG meat was perceived to be stringier than that of the MM, but there was no significant difference in Warner-Bratzler shear force values. Tenderness declined with age in both species and there was also a tendency for goat meat to be less juicy than lamb. Chevon had a more pronounced aftertaste than lamb. No objective differences could be distinguished between the colour of the cooked chevon and lamb. There was a tendency for fresh lamb to have a higher a*-value (redness) than chevon. Although diet did not influence drip loss, drip loss increased with an increase in slaughter age. Only after 56 days did the MM's m. semimembranosus have a significantly higher drip loss than the BG's (LE: 4.84 vs. 3.43%; HE: 4.72 vs. 3.32%). In the m. semimembranosus of both species, cooking loss increased with an increase in slaughter age. Since diet did not influence the growth, carcass weight distribution, water holding capacity, colour, shear force values or organoleptic qualities of chevon, BG's may be finished on a diet with a lower ME-value than that usually formulated for sheep, without a reduction in performance. This may render a direct economic advantage for BG feedlot finishing. Meat from young feedlot goats is not inferior to that of lamb and it has a higher protein percentage and lower fat percentage. Therefore, it can be considered as a healthy food commodity, especially among low-income groups or people wishing to consume a low calorie diet. / AFRIKAANSE OPSOMMING: 'n Vergelykende analise van nutriëntverbruik en vleiskwaliteisparameters van Boerbokke en Suid-Afrikaanse Vleismerino's: Een van die hoofredes waarom die vraag na vleis die aanbod oorskrei, is die feit dat die mens tot op hede net op 'n paar dierspesies as bron van vleis gekonsentreer het. Benutting van niekonvensionele spesies, soos bokke, kan aanbeveel word ten einde die globale vleisproduksie en -verbruik te verhoog. Ten spyte van die feit dat Suid-Afrika oor baie gedomestikeerde herkouerspesies beskik, is vleisverbruik in die verlede tot hoofsaaklik skape en beeste beperk. Bokke is tot 'n mindere mate gebruik. Dit kan gedeeltelik toegeskryf word aan die algemene siening dat bokvleis ondergeskik aan skaap- en beesvleis is. Verskeie teenstrydighede ten opsigte van vergelykings tussen bokke en skape se groei, karkaseienskappe en vleissamestelling bestaan in die literatuur. Teenstrydige resultate ten bpsigte van gemiddelde daaglikse toename (GOT), uitslagpersentasie, karkasgewigverspreiding en organoleptiese eienskappe (veral taaiheid, sappigheid en geur) van diere afgerond onder intensiewe/voerkraal-toestande, kom veral voor. Hierdie projek is vervolgens uitgevoer ten einde meer inligting ten opsigte van die groei, karkas- en organoleptiese eienskappe, sowel as die chemiese samestelling van die vleis van Boerbok (BB) lammers in vergelyking met Suid-Afrikaanse Vleismerino (VM) lammers, onder voerkraal-toestande grootgemaak, te verkry. Twee-en-dertig BB lammers en 32 VM lammers is vir hierdie studie gebruik. AI die diere is gekastreer en gespeen voor hulle in die voerkraal geplaas is. Twee verpilde diëte (gevoer aan 16 diere/spesie) met óf 'n lae (LE, 8.9 MJ/kg DM) óf 'n hoë (HE, 10.9 MJ/kg DM) metaboliseerbare energievlak is individueel, ad lib, vir óf 28 óf 56 dae aan die diere gevoer. Voer- en waterinname, GOT en voeromsettingsdoeltreffendheid (VOD) is gemonitor. Gedurende die laaste week van die voedingsproef is 12 BB'e en 12 VM's gebruik ten einde die verteerbaarheid van die twee diëte te bepaal. Na 28 of 56 dae is die diere geslag en die karkasse in Suid-Afrikaanse kommersiële snitte verdeel. Die m. semimembranosus en 8-9-10-rib snit van elke karkas is verwyder vir bepaling van chemiese samestelling, drupverlies, kookverlies, skeurwaardes en kleurbepaling. Die m. gracilis is uit die agterbeen uitgehaal en vir sensoriese evaluering gebruik. VM's het betekenisvolle hoër GOT's as BB'e (bv. VMHE56: 0.281; BBHE56: 0.162 kg/dag) gehad. Binne 'n dieet was daar geen verskille (P>0.05) in VOD tussen BB'e en VM's nie en net die VM's se VOD het tussen die LE- en HE-dieet verskil (bv. BBLE28: 7.65; BBHE28: 6.37; VMLE28: 8.73; VMHE28: 5.56 kg voer/kg gewigstoename). BBLE het die droë materiaal (DM), ruproteïen (RP) en energie meer effektief verteer en het 'n hoër energieretensie as VMLE gehad. Die twee diëte het dieselfde ME-waarde vir die bokke gehad, wat bevestig dat bokke net so goed op 'n laer kwaliteit voer presteer as op 'n dieet van 'n hoër kwaliteit. Stikstofretensie is nie deur spesie of dieet beïnvloed nie. Die BB het 'n 49% laer (P<0.01) waterinname per kg massatoename op beide die HE- en LE-dieet gehad. Beide spesies het 'n laer (P<0.01) waterinname op die hoë as die lae energie dieet gehad. Verder het die BB ook 'n daaglikse waterinname van slegs 171 ml/kg075 gehad in vergelyking met die 302 ml/kgO.75van die VM. Die gewig van die lewer, leë pens, kop en pote (as persentasie van leë liggaamsgewig) was hoër vir bokke as vir skape. Die VM's se velle was betekenisvol swaarder, waarskynlik as gevolg van wolgroei. Beide niervet en kanaalvet het toegeneem met 'n toename in slagouderdom. Die diere wat na 56 dae in die voerkraal geslag is, het betekensivol langer en dieper karkasse gehad as dié na 28 dae. Binne 'n dieet en slagouderdom, het die skape breër en dieper (P<0.05) karkasse as die bokke gehad. BB'e het betekenisvol minder gewig per eenheid karkaslengte en dus maerder karkasse as VM's gehad. Dieet-energievlak het geen betekenisvolle effek op die verspreiding van karkasgewig by bokke gehad nie. VM's het egter swaarder karkasse (LE: 19.87 vs. 15.28 kg; HE: 24.01 vs. 17.05 kg) en proporsioneel swaarder ribbes en boude as BB'e gehad. Dieet of slagouderdom het nie 'n betekenisvolle effek op die chemiese samestelling (vog, vet, proteïen en as) van die m. semimembransous gehad nie, maar VM's het laer (P<0.05) vogwaardes as BB'e gehad. In die 8-9-10-rib snit het BB'e betekenisvolle hoër vog en proteïen, maar laer vet- en energiewaardes as VM's gehad. In beide spesies het DM, vet en energiewaardes toegeneem met 'n toename in slagouderdom. BG'e het 'n betekenisvolle hoër konsentrasie in 11 van die 18 gemete essensiële aminosure in hul 8-9-10-rib snitte gehad in vergelyking met VM's. Bokkarkasse het ook hoër Ca, K, Mg, N en P-vlakke as skaapkarkasse gehad, ongeag die dieet. Daar was 'n neiging vir die bok m. semimembranosus om 'n laer Fe-inhoud as dié van die skaap te hê. BB-karkasse het 'n laer cholesterol-inhoud as skaapkarkasse (66.77 vs. 99.28 mg/100g, onderskeidelik) gehad. Palmitiensuur (C16:0), steariensuur (C18:0) en oleïensuur (C18:1n9) het die grootste proporsies van die vetsure in beide die m. semimembranosus en 8-9-10-rib snit van beide spesies uitgemaak. Op 'n LE-dieet was daar geen verskil tussen die versadigde (SFA) tot onversadigde (UFA) vetsuur-verhouding van bok- en skaapvleis nie. Op 'n HE-dieet het skaapvleis egter 'n betekenisvol hoër SFA:UFA-verhouding as bokvleis gehad (m. semimembranosus: 0.842 vs. 0.689; 8-9-10-rib snit: 1.40 vs. 0.892, onderskeidelik). Organolepties is 'n verskil tussen bok- en skaapvleis gevind. Elkeen het 'n spesifieke spesiegeur, wat onafhanklik van die dieet was. Bokvleis is waargeneem as meer veselrig as skaapvleis, maar daar was geen verskil in Warner-Bratzler skeurwaardes nie. In beide spesies het sagtheid afgeneem met 'n toename in ouderdom en daar was 'n neiging vir bokvleis om minder sappig as lamsvleis te wees. Bokvleis het ook 'n meer pertinente nasmaak as lam gehad. Geen objektiewe verskil kon tussen die kleur van gekookte skaapen bokvleis onderskei word nie. Daar was egter 'n tendens vir vars lamsvleis om 'n hoër a*- waarde (rooiheid) as bokvleis te hê. Alhoewel dieet nie 'n invloed op drupverlies gehad het nie, het drupverlies toegeneem met 'n toename in slagouderdom. Slegs na 56 dae het die VM se m. semimembranosus 'n hoër (P>0.05) drupverlies as dié van die BB getoon (LE: 4.84 vs. 3.43%; HE: 4.72 vs. 3.32%, onderskeidelik). In die m. semimembranosus van beide spesies het kookverlies toegeneem met 'n toename in slagouderdom. Aangesien dieet nie 'n effek op die groei, karkasgewig-verspreiding, waterhouvermoë, kleur, skeurwaardes of organoleptiese eienskappe van bokvleis gehad het nie, kan BB'e op 'n dieet met 'n laer ME-waarde as wat normaalweg vir skape geformuleer word, afgerond word, sonder om 'n verlaging in produksie te verwag. Dit mag 'n direkte ekonomiese voordeel vir afronding van BB'e in die voerkraal inhou. Vleis van jong voerkraalbokke is nie minderwaardig teenoor die van skape nie e-n dit het 'n hoër proteren- en laer vetpersentasie. Dus kan bokvleis as 'n gesonde voedselbron gesien word, veralonder lae-inkomste groepe of mense wat 'n lae kalorie-dieet wil inneem.

Diet selection and its variation due to difference in forages nutritive value are central processes in plant-herbivore interactions. An incorporating of these parameters may allow predicting diet selection patterns which are a basic underpin for sustainable vegetation management and profitable animal production. To achieve these issues many studies were done two of which were run to study the browse-browser interactions in a sub-humid subtropical savannah, a herd of goats was used as a model browser in natural pasture. Other studies evaluated the nutritive value of five plant species which were the most selected by goats. The objectives of this study were to (i) determine the seasonal patterns of diet selection of goats on woody species and their nutritive value and (ii) to predict the diet selection. The secondary objectivrs were to (i) investigate how plant characteristics such as plant morphology (spinescence, and broad vs. fine leaves), phenology (evergreen vs. deciduous species) and plant chemistry (nitrogen, neutral detergent fibre, acid detergent fibre, acid detergent lignin, condensed tannin, cellulose and hemicellulose) are relate to the diet selection patterns and to (ii) evaluate the nutritive value of the most plant species selected by goats during the different seasons. Two experiments were conducted at Owen Sitole College of Agriculture, KwaZulu-Natal, to determine diet selection of goats grazing/browsing in Zululand Thornveld. The first experiment was done in the early wet season (November 2007) and late wet season (March/April 2008) while the second experiment was conducted in the dry season (June/July 2008), early wet season (November/December 2008) and late wet season (February/March 2009). The relative abundance of browse species in the veld was determined and used to estimate the selection index. In the first part, diet selection was estimated using (i) direct observation of animals (account bouts) by observing every one minute two goats while they were foraging with others for 3 hours in the morning and 1.5 hours in the afternoon on alternate days for a total of six days and (ii) an indirect plant-based method by observing at regular intervals 40 marked branches on ten plants of each browse species every two days for a total of six days. The browse species observed were: Gymnosporia senegalensis, Acacia nilotica, Acacia karroo (Acacia natalitia), Scutia myrtina and Dichrostachys cinerea. In both seasons, the three most selected species according to the plant-based observations were S. myrtina, A. karroo and D. cinerea. Consistently, A. nilotica experienced moderate defoliation and G. senegalensis the least. However, on the basis of the selection index, the species followed the order: A. nilotica > D. cinerea > A. karroo > S. myrtina > G. senegalensis in the early wet season and A. nilotica > S. myrtina > D. cinerea > A. karroo > G. senegalensis in the late wet season. Both methods did not rank species in the same order. The selection index was negatively (P<0.05) correlated to neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). In the second part, observations were taken on feeding time of two goats, randomly selected per day for 7-8 days. Observations were made during active foraging periods for 2 hrs in the morning and 1.5 hrs in the afternoon. The duration of each feeding bout and the species of woody plant from which bites were cropped at each feeding station were recorded. Season and plant species affected diet selection and preference. The five main species selected (utilized) by goats in decreasing order were S. myrtina, A. nilotica, D. cinerea, Acacia natalitia and Chromolaena odorata. Scutia myrtina was the most preferred (highest utilisation relative to availability) in the dry season while D. cinerea comprised the greatest proportion in the early and late wet seasons. Scutia myrtina was most preferred in the dry and early wet seasons while A. nilotica was most preferred in the late wet season. Spinescent species were generally selected more than non-spinescent species in all seasons, while fine-leaf and deciduous species were selected more than broad-leaf and evergreen ones in the wet seasons. However, preference for broad-leaf and evergreen species increased in the early wet season. Although plant chemistry varied across seasons, it did not explain the preference of goats for various plant species in this study. Instead, effects of chemistry were species- specific. The nutritive value of the five main species selected by goats was evaluated by chemical composition, in vitro gas production, in vitro degradability and in sacco degradability. Two experiments were conducted for the in vitro studies, the first experiment was to test the effect of season and species, while the second experiment tested the biological effect of tannins using polyethylene glycol 4000 (PEG). The PEG treatment was applied to samples of the early and late wet seasons only. The parameters were maximum gas production (GP), degradation rate (C), lag time (lt), maximum rate of GP at the point of inflection (μ), half time to the maximum gas volume(T1/2), gas produced from fermentation of soluble and slowly degradable fractions (A and B, respectively), their degradation rates (c1 and c2, respectively), apparent (ApDeg) and true degradability (TrDeg), microbial yield (MY), partitioning factor (PF), degradation efficiency factor (DEF) and short chain fatty acids (SCFA). There were wide variations among seasons and species in crude protein (CP), NDF, ADF and condensed tannins. Season and species affected kinetics of gas production, GP, TrDeg, MY, PF and SCFA. Chromolaena odorata had the highest CP (185.8-226.4 g kgˉ¹), GP (87.3-104.1 ml gˉ¹ DM), gas produce from soluble (47.6-50.9 ml gˉ¹ DM) and insoluble (39.8-50.9 ml gˉ¹ DM) fractions during the three seasons compared to other browse species. The TrDeg ranged from 634 to 856 g kgˉ¹ DM. The total SCFA varied between seasons and among species. The addition of PEG decreased TrDeg and PF, and increased GP and total SCFA. The GP, its degradation rate (C) and gas from the soluble fraction were positively correlated to CP without and with PEG. Gas from the soluble fraction was negatively correlated to NDF, ADL and CT; and GP to CT without PEG. In the in sacco study, the parameters of dry matter (DM) and nitrogen (N) degradability were soluble (a) and slowly (b) degradable degradability, the degradation rate (c), potential degradable (PD), effective degradability (ED) and lag time (lt). Season affected PD of DM degradability and ED of both DM and CP. Browse species and its interaction with season affected all parameters except b fraction of CP and interaction did not affected PD of CP. Chromolaena odorata had the highest estimated parameters of degradation during the three seasons compared to other browse species. Based on PD and ED, the plant species followed this decreasing order: C. odorata, A. nilotica, A. natalitia, S. myrtina and D. cinerea. All parameters were positively correlated to CP except the a and b fractions of DM and CP, respectively, and lt of both DM and CP. All parameters were negatively correlated to NDF, ADF and ADL except the b fraction and rate of degradation. Condensed tannins (CT) were negatively correlated with all parameters except the b fraction and PD of DM and CP, and lt of DM degradation. Cellulose was negatively correlated with a of DM and lt of CP degradation. The broad objective of this study was to assess whether plant characteristics, in sacco degradability, in vitro gas production, digestibility or chemical composition (NDF, ADF, ADL, CT and CP) could predict the selection of browse species. The parameters were selection index, plant characteristics (spinescence, or leaves phenology), chemical composition, in vitro gas production, in vitro degradability and in sacco degradability parameters. Most of these parameters were poor for predicting selection by goats of browse species. Spinescence (spn), leaves phenology (phen), NDF, CP and CT accounted for 86% of the variation in selection index (y) = -5.91 - 0.01CT - 0.002NDF + 0.02CP + 6.18spn + 2.43phen; (R2=0.86; n=20; RMSE=0.406; P<0.001; for phen, 1 = evergreen, 0 = deciduous; for spn, 1 = spinescent, 0 = spineless). It was concluded that in vitro gas production, in vitro degradability and in sacco degradability were poor predictors of selection index of browse species used by goats. Spinescence, leaf phenology, condensed tannins, CP and NDF were predictors of diet selection index and suggested that these plant species have potential to be used as feed supplements. Chromolaena odorata has the highest potential as feed protein source in goats. The addition of PEG (tannin binding agent) emphasizes that the inhibitory effect of tannins on rumen microbes was great in tannin-rich feeds. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Diet selection and foraging efficiency are primary driving behavioural processes in mammalian herbivore plant interaction. They determine the quality of production and also impact on vegetation, necessitating managerial inputs that will sustain productivity and conserve or improve on its plant species composition. In view of a better understanding of browse/browser interaction in subtropical arid savannah, Nguni goats were adopted as our model browser considering their socioeconomic importance to local, regional and global economy. The primary objective of this research was to determine the seasonal and plant species trend of diet selection indexed by intake and foraging efficiency indexed by intake rate. The secondary objective was to investigate how plant morphological variables such as spinescence, shoot morphology such as long shoots as opposed to short shoots, and broad as against fine leaves, phenological variables such as evergreen versus deciduous species, and plant chemical components including: crude protein, neutral detergent fibre (NDF), acid detergent fibre (ADF), hemicellulose, cellulose, acid detergent lignin and condensed tannins relate and possibly explain the observed patterns. Six browse plants, Acacia nilotica, Acacia robusta, Ehretia rigida, Euclea crispa, Rhus lancea and Ziziphus mucronata were used in the first experiment to determine short term intake during the dry and rainy seasons. In the second experiment, 10 browse plants: Acacia nilotica, Acacia robusta, Combretum epiculatum, Dicrostachys cinerea, Ehretia rigida, Euclea crispa, Gymnosporia buxifolia, Rhus lancea and Ziziphus mucronata were used to determine short term intake rate in the dry, early rainy and late rainy seasons. Diet selection was significantly affected by species (F5,60= 31.87 ; p< 0.05) and the interaction between seasons and species (F,60= 2.52; p= 0.039). Intake was not significantly higher in the rainy relative to the dry season, 3.94 ± 0.42a gDM compared to 3.57 ± 0.42a gDM. Rhus lancea and A. robusta were the most preferred species in both seasons, while Z. mucronata was more preferred in the dry season than E. crispa but in the rainy season it was the opposite. Dichrostachys cinerea and A. nilotica were the least preferred in both seasons, but with improved intake of D. cinerea in the rainy season, whereas that of A. nilotica declined significantly. Intake of plant species with long shoots, which were also broad leafed, was significantly higher than that of old short shoot species (t= -3.99; df= 65.80; p= 0.0002). Similarly, intake of evergreen species was significantly higher than that of deciduous species (t= 5.22; df= 34.02; p< 0.0001). Cellulose in the rainy season positively correlated with intake (r= 0.85; n= 6; p= 0.031), bite number cropped (r= 0.98; n= 6; p= 0.001) and browsing time (r= 0.93; n= 6; p= 0.007). In the dry season there was no correlation of any plant chemical components with intake except cellulose that correlated with the intake variable of bite size (r= 0.87; n= 6; p= 0.023). The following regression equation was generated from the correlation to model intake: Intake= 0.68 + BS (3.07), (R2= 0.71; p< 0.05), where BS= bite size. Intake rate varied amongst species (p< 0.05), as well as seasons (p< 0.05). Instantaneous intake rate in the dry season were highest for A. caffra and G. buxifolia, followed by C. apiculatum, R. lancea, E. crispa, A. robusta and Z. mucronata. The bottom tier comprised of E. rigida, D. cinerea and A. nilotica. At the onset of the rainy season, A. robusta, A. caffra and R. lancea had the highest instantaneous intake rate, followed by C. apiculatum, E. crispa and Z. mucronata. The lowest instantaneous intake rates were derived from D. cinerea, E. rigida, G. buxifolia and A. nilotica. At late rainy season, A. robusta, A. caffra, C. apiculatum, E. crispa and R. lancea yielded the highest intake rate, followed by D. cinerea, G. buxifolia and Z. mucronata in the middle tier, and the least were derived from E. rigida and A. nilotica. Acacia caffra, A. robusta, R. lancea, C. apiculatum and E. crispa featured amongst species with the higest intake rate in all three seasons, whereas G. buxifolia from which one of the highest intake rates was derived in the dry season declined to amongst those with the least in both early and late rainy seasons. Ehretia rigida, D. cinerae and A. nilotica were consistent in all three seasons as the least efficiently foraged Browses with long shoots were more efficiently foraged upon than those with short shoots (t= -3.2; df= 284.64; p< 0.002). Evergreen plant species yielded higher instantaneous intake rate relative to deciduous species (t= 2.02; df= 278.01; p< 0.044). Intake rate of spinescent relative to spineless species was not significantly different but more bites were cropped from spinescent relative to spineless species (t= 2.80; df= 256.77; p= 0.006). Bite sizes were smaller for spinescent relative to spineless species (t= -3.30; df= 227.4; p= 0.001). There were significant positive correlations of cellulose with intake rate (r= 0.7; n= 10; p= 0.023), and with condensed tannins (r= 0.7; n= 10; p= 0.022) in the dry season. Additionally, cellulose also had a positive correlation with bite size in the same season (r= 0.7; n= 10; p= 0.016). At early rainy season, there was no correlation of intake with any of the plant chemical components, whereas, NDF (r= 0.6; n= 10; p= 0.044), hemicellulose (r= 0.8; n= 10; p= 0.012) and condensed tannins (r= 0.7; n= 10; p= 0.032) all correlated positively with browsing time at early rainy season. The following regression equations were derived to model intake rate and some intake rate related variables: (1) intake rate= 0.433 + BSDM (0.081), R2= 0.68, p< 0.05 and BSDM= bite size dry matter; (2) Bite rate= 0.503 –BSDM (0.147), R2= 0.597, p< 0.05 and BSDM= bite size dry matter; (3) Bite size dry matter= 1.713 – BR (4.210), R2= 0.597 ,p< 0.05 and BR= bite rate, and (4) Intake dry matter= 3.804 + BSDM (0.865), R2= 0.607, p< 0.05 and BSDM= bite size dry matter. Diet selection and foraging efficiency were both influenced more by shoot and leaf morphology than by spinescence. Plant chemistry on the other hand had diverse and inconsistent effect on diet selection and foraging efficiency trends. The results therefore have important and far reaching implications for Nguni goat and goat production as a whole in the bush veld of Gauteng and related ecological zones. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Goats are found in almost every country and are an important source of protein and produce lactose-free milk. In South Africa, survival rates of goat kids are low, mainly due to malnutrition. Intensive goat production systems based on cultivated pastures were evaluated, at various stocking rates to evaluate the effects of improved nutrition on goat production. The pastures chosen to be evaluated for goat production were Pennisetum clandestinum (Kikuyu) and Secale cereale (Stooling rye). Kikuyu is one of the more important dryland summer pasture species in KwaZulu-Natal. Three stocking rates of goats on kikuyu were evaluated using ewes with kids. When analysing the period to weaning, the ewes lost weight in all stocking rate treatments and for both years. The years had a significant effect on weight loss (P<0.001; R²=95.7%) with a mean ADG of -0.0267 kg.animalˉ¹.dayˉ¹. There was a significant difference between ADGs between stocking rates, with ADGs of -0.0157, -0.026 and -0.0384 kg.animalˉ¹.dayˉ¹ at stocking rates of 30, 45 and 60 goats.haˉ¹ respectively (P<0.001; R²=95.7%). The analyses of the entire grazing period showed no significant difference in ewe ADGs between treatments, but a significant difference between the two years (P=0.03), with a mean ADG of -0.0205 kg.animalֿ¹.dayֿ¹. There was no significant difference between kid masses between treatments. There was a significant difference between kid performance between years (P<0.001; R²=21.8%). However, factors such as ewe start mass (P<0.001) and whether the kid was a singleton or a multiple (P=0.015) had an influence on kid ADG, while gender had no significant effect (P=0.446). Interpretation of the combined ewe plus kid weight revealed that the high stocking rate produced the highest total mass per hectare (P<0.001) with an overall mean of 2377 kg.haˉ¹. Kid ADG was positively correlated to ewe ADG (P=0.013; R²=5.8%) although this was not a strong relationship. Protein was negatively correlated to pasture height (P=0.036; R²=30.8%) and had a quadratic relationship with ADG (P<0.001; R²=48.4%) with maximum ADG occurring at protein levels of 26.17%. Rainfall was different between the two seasons, which affected pasture growth, with the stocking rates in the second year being too low, so the maximum stocking rate per hectare was not reached. Stooling rye is a pasture used predominantly in South Africa and is a good source of high quality winter feed. Four stocking rates were evaluated over winter, using pregnant ewes. Rainfall was not an important variable since supplementary irrigation was given and the difference in temperatures between the years was negligible. The rate of weight gain showed a similar response for both years with the level of weight gain varying significantly between years (P=0.001; R²=90.2%). The regressions for ADG on stocking rate were determined and were y=0.2340-0.00293x for 2001 (P=0.151; R²=58.0%) and y=0.1292-0.002198x for 2002 (P=0.137; R²=61.6%). Gain per hectare was determined, as were the stocking rates at which maximum gain per hectare were achieved and this was determined to be 40 goats.haֿ¹ during 2001 and 29 goats.haֿ¹ for 2002. The respective ADGs at these stocking rates were 0.1168 and 0.0633 kg.dayֿ¹ and daily gains.haֿ¹ were 4.672 and 1.898 kg.haֿ¹.dayֿ¹ respectively. Herbage analyses revealed that there were extremely high levels of protein in the pasture (33.87%) even though the pasture was not excessively fertilised. Average daily gain was negatively related to NDF levels (P=0.006; R²=38.4%). ADF levels (P<0.001; R²=48.4%) and NDF levels (P<0.001; R²=60.4%) showed a quadratic relationship with pasture age. Blood serum revealed that selenium levels in all treatments were lower than the normal range, while all other minerals were within the normal range. To maximise animal performance, the highest quality pasture should be offered to producing animals, namely growing animals. The seasonal variation between years has a large effect on the performance of goats on pastures. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Effects of Acacia karroo supplementation on meat quality of Xhosa Lop-Eared goats The objective of the study was to determine the effects of A. karroo supplementation on the quality of meat from Xhosa lop-eared goats. Eighteen castrated 4-month-old Xhosa lop-eared male kids were kept at the University of Fort Hare Farm until slaughter. At the beginning of the experiment the goats had a mean body weight of 13.5 ± 0.31 kg (mean ± S.E.) and a mean body condition score (BCS) of 3.3 ± 0.16 (mean ± S.E.). From birth until weaning the kids were kept on natural pastures with their mothers. After weaning the goats were housed in an open sided barn for a period of 60 days, and were fed 500 g/head/day of Medicago sativa hay covering their maintenance and growth needs. For the purpose of the experiment, the goats were randomly divided into two balanced treatment groups of nine goats each, supplemented group (AK) and non-supplemented group (NS). The supplemented group received an additional 200g per head per day of fresh A. karroo leaves collected each day for two months. Supplementary feed was given to the goats individually in feeding troughs. The kids were slaughtered at 60 days old and samples for meat quality assessment were taken from the Longistimus dorsi muscle. The effect of A. karroo supplementation on meat quality measurements such as ultimate pH, colour and cooking losses of meat from indigenous Xhosa lop-eared goats were determined. The effect of A. karroo supplementation on the consumer sensory characteristic scores of the meat from the indigenous Xhosa lop-eared breed was also determined. There was a significant effect of the A. karroo supplementation on the meat quality measurements except for L* and a* colour coordinates. Meat from the A. karroo supplemented goats had lower pH and cooking loss scores than that of the non-supplemented goats. Acacia karroo supplementation improves meat tenderness and juiciness. There were no significant effects of A. karroo supplementation on the flavour and off- iv flavours of the meat from the supplemented goats. However, thermal preparation and consumer background had a significant effect on the meat sensory characteristics. The cooked meat had significantly higher sensory scores than the roasted meat. Female consumers reported higher sensory scores than male consumers. Consumers of different tribes and ages also reported significantly different sensory scores of meat from indigenous Xhosa lop-eared goats. Therefore, this study indicated that A. karroo supplementation can be fed to the Xhosa lop-eared goats to improve their meat quality.