The occurrence and concentration of substances like glycosides, alkaloids, certain amino acids, and, especially, phenolics in vegetation has been seen as a defense against environmental perturbations. Whether this phenomenon is associated with the disruptive effect of man, herbivore predation or the invasion of arthropods and microorganisms remains to be ascertained by ecologists. However, contemporary research shows that most so-called secondary metabolites in plants render them less sensitive to adverse factors in the natural environment. Likewise, herbivores that adapted to chemical defense in plants were rewarded with wider food source and might have been able to more efficiently exploit rapidly changing foraging environments. This study focuses on relationships between goats, their ruminal microbes and tannin-rich plants in a central Arizona chaparral vegetation type dominated by shrub live oak (Quercus turbinella). The study tested hypotheses involving goat dietary selection, estimated through microhistological analysis of feces; phenolic profile of shrub live oak, expressed as condensed and hydrolyzable tannins, protein binding capacity of oak leaves extract, expressed as bovine serum albumin (BSA) precipitation; and apparent dry matter digestibility of mature and immature oak leaves by goat ruminal microbes measured at 6, 12, 24 and 48 hours. Findings of this research indicated that goats prefer leaf and shoot ends of shrubs, mainly shrub live oak, despite the constant high concentration of tannins in that plant. Hydrolyzable tannins in oak are synthesized during summer/fall and late spring, and the synthesis of condensed tannins is mostly restricted to winter and early spring. Precipitation of BSA by extract of oak leaves, apparently associated with hydrolyzable tannins, did not discourage oak consumption by goats. The digestibility of younger and older oak leaves was more influenced by time of incubation than level of phenolics in plant tissue. This research emphasizes the adaptability of goats to ecological zones where presence of toxins and digestion reducing compounds in plants adversely affects survival and fitness of non-adapted herbivores.

Two methods of estimating the intake of a 25% leucaena : 75% grass hay diet by young male Boer goats were assessed, (a) The purine derivative technique which uses the urinary excretion of purine derivatives (expressed relative to creatinine concentration in the same sample) as an index of feed intake, and (b) the conventional marker method, utilizing chromic oxide (Cr₂O₃) contained in gelatin capsules and dosed twice daily, as the marker. Following a prerun the two techniques were compared in three runs of an indoor experiment. In each run 10 goats were randomly allocated to five feeding levels (500 to 1100 g fodder d ¯¹ on air dried basis). A preliminary and an adaptation period during which goats were dosed with the Cr₂O₃ and fed their daily feed allowance, was followed by a 4 day collection period during which spot samples of urine were collected and analysed for allantoin and creatinine (allantoin being used instead of total PDs) and faecal samples were collected for chromium analysis and percentage dry matter determination. For the first two runs, two grab samples per day for each goat were bulked and analysed for chromium content. For the last run, the total daily faecal collection was subsampled and analysed for chromium. Work was done in metabolic crates to determine the effect of time of collection on the ratio of allantoin : creatinine (A/C) in spot urine samples and it was found to non-significant (P>0.05). Linear regressions of: (a) feed intake expressed per unit metabolic mass (g.d ¯¹.LW ¯°∙⁷⁵ (I_mmass)) against A/C ratio; (b) faecal output (g d ¯¹) against feed intake (g d ¯¹); and (c) faecal chromium concentration (mg kg ¯¹) against faecal output (g d ¯¹) were fitted to the data. During the prerun, only regression (a) was fitted and was non-significant (P>0.05), showing no trend at all. For the first true run, the regression of I_mmass against A/C ratio was significant and the correlation was high (P≤ 0.001, R² [A] 0.715, n = 10) but for the second and third runs, the correlations only became significant when the apparent outliers were discarded from the data. (Run 2: P≤ 0.001, R² [A] 0.824, n = 8; Run 3: P≤ 0.05, R² [A] 0.430, n = 9). It was concluded that the relation between I_mmass and A/C ratio is not well enough defined to be used for predictive purposes. When regression (b) was investigated, all the runs produced significant results (P≤0.001, P≤0.01, P≤ 0.001 for runs 1,2 and 3 respectively) however the correlations were not as high as expected (R² [A] being 0.714, 0.565 and 0.863 respectively). For the regression of faecal Cr concentration against faecal output (regression c), all runs showed significant relations (P< 0.001, P< 0.0001, P:s 0.001 for runs 1,2 and 3 respectively) and the correlations were high (R²[A] being 0.836, 0.837 and 0.912 respectively). The data from the three runs were pooled and single equations established for regressions (b) and (c) to allow for the prediction of intake from faecal chromium concentration. Faecal output = feed intake * 0.448 + 19.341 (P≤ 0.001, r 0.853, R² [A] 0.718, SE 25.664, n - 30) Faecal chromium concentration = faecal output * -241.547 + 1.315E+05 (Ps 0.001, r 0.904, R² [A] 0.811, SE 5603.788, n = 30). In vitro figures were determined for a range of leucaena : hay mixes but no apparent trend was found between percentage leucaena in the mix and the digestibility of the mix. These results compared favourably with in vivo results obtained for a 25% leucaena : 75% hay mix. Neither technique proved entirely satisfactory, but the external marker method was found to be more effective than the purine derivative technique. More work is required especially with respect to the latter method. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.

The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.

Made available in DSpace on 2015-08-20T17:10:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-03. Added 1 bitstream(s) on 2015-08-20T17:25:35Z : No. of bitstreams: 1 000844813.pdf: 750137 bytes, checksum: 455e0184a4c4de470cab844b2d958c25 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O experimento foi conduzido com o objetivo de avaliar a substituição do milho pela raspa de mandioca na dieta de cabras Alpinas sobre o consumo de massa seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), carboidratos não fibrosos (CNF), nutrientes digestíveis totais (NDT) e energia metabolizável (EM), sobre a produção e composição do leite, digestibilidade aparente da MS, PB e FDN e também sobre o comportamento ingestivo dos animais em pastagem de capim-tobiatã. O experimento teve duração de 72 dias, em que foram utilizadas oito cabras em lactação, distribuídas em dois quadrados latinos (4 x 4) balanceados. Os tratamentos consistiram em níveis de 0, 33, 67 e 100% de substituição do milho pela raspa de mandioca no concentrado. A inclusão da mandioca proporcionou aumento linear no consumo de CNF e na digestibilidade da MS. A substituição não influenciou a produção e composição do leite e no comportamento ingestivo dos animais, dessa maneira, a raspa de mandioca pode substituir totalmente o milho no concentrado fornecido às cabras sem trazer prejuízos à produção de leite. / This study was conducted to evaluate the substitution of corn by cassava in supplementation of Alpine does on dry matter intake (DM), crude protein (CP), neutral detergent fiber (NDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN) and metabolizable energy (ME), yield and milk composition, apparent digestibility of DM, CP and NDF and also on the grazing behavior in tobiatã grass. The experiment lasted 72 days, were used eight lactating does, distributed in two Latin squares (4 x 4) balanced. The treatments were as following: 0, 33, 67 and 100% replacement of corn by cassava. The inclusion of cassava caused a linear increase in the NFC consumption and DM digestibility. The substitution had no effect on milk yield and feeding behavior of the animals in this way, cassava can replace totally the corn in the supplement provided to does without harming the production of milk.

Orientador: Heraldo César Gonçalves / Banca: Paulo Roberto de Lima Meirelles / Banca: Marco Aurélio Factori / Banca: Otavio Rodrigues Machado Neto / Banca: Kleber Tomasde Resende / Banca: Carla Maris Machado Bittar / Resumo: O experimento foi conduzido com o objetivo de avaliar a substituição do milho pela raspa de mandioca na dieta de cabras Alpinas sobre o consumo de massa seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), carboidratos não fibrosos (CNF), nutrientes digestíveis totais (NDT) e energia metabolizável (EM), sobre a produção e composição do leite, digestibilidade aparente da MS, PB e FDN e também sobre o comportamento ingestivo dos animais em pastagem de capim-tobiatã. O experimento teve duração de 72 dias, em que foram utilizadas oito cabras em lactação, distribuídas em dois quadrados latinos (4 x 4) balanceados. Os tratamentos consistiram em níveis de 0, 33, 67 e 100% de substituição do milho pela raspa de mandioca no concentrado. A inclusão da mandioca proporcionou aumento linear no consumo de CNF e na digestibilidade da MS. A substituição não influenciou a produção e composição do leite e no comportamento ingestivo dos animais, dessa maneira, a raspa de mandioca pode substituir totalmente o milho no concentrado fornecido às cabras sem trazer prejuízos à produção de leite. / Abstract: This study was conducted to evaluate the substitution of corn by cassava in supplementation of Alpine does on dry matter intake (DM), crude protein (CP), neutral detergent fiber (NDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN) and metabolizable energy (ME), yield and milk composition, apparent digestibility of DM, CP and NDF and also on the grazing behavior in tobiatã grass. The experiment lasted 72 days, were used eight lactating does, distributed in two Latin squares (4 x 4) balanced. The treatments were as following: 0, 33, 67 and 100% replacement of corn by cassava. The inclusion of cassava caused a linear increase in the NFC consumption and DM digestibility. The substitution had no effect on milk yield and feeding behavior of the animals in this way, cassava can replace totally the corn in the supplement provided to does without harming the production of milk. / Doutor

Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Little research has been done on natural feed additives which enhance milk production in dairy animals. Fenugreek (Trigonella foenumgraecum) is a member of the legume family and is found in India, Middle East, North Africa and South Europe. Fenugreek is used as an herb in traditional medicine to promote lactation in lactating women. It also influences the lactation performance in ruminants such as dairy cows, water buffaloes and dairy goats. Diocin is a natural saponin found in Fenugreek and has structural similarity to oestrogen, which leads to an increased release of growth hormone (GH) and ultimately milk production. Three different trials were carried out to investigate Fenugreek’s effects. Each trial consisted of three treatment groups where dairy goats were randomly assigned. Nutrifen®, NutrifenPlus® and a control treatment served as the three treatments used in this study. Forty-eight goats per treatment group were used in the first trial where the main objective was to evaluate Fenugreek’s effect on milk production and milk composition. The second trial consisted of eight goats per treatment group, where Fenugreek’s effect on the in vivo and in vitro digestibility of the feed served as the main objective of this study. In the final part of the study, growth hormone found in plasma was subsequently investigated using the same goats from trial two. Fenugreek’s effect on elevating GH levels was the objective from the third part of the study. The first trial showed promising results in terms of an increase in milk production (P = 0.01) from dairy goats using the Nutrifen® treatment and an increase in milk lactose (P = 0.03) using the NutrifenPlus® treatment. Blood cholesterol and cholesterol content found in the milk did not differ between treatments used. Apparent digestibility of the total digestible nutrients (TDN) from the feed did not increase and did not differ between treatments and therefore concluded that the dairy goats digested the different treatments with similar efficiency regardless of the additive added to the feed. Growth hormone levels found in plasma also did not differ between treatments used in the third part of the study. Variation was found in GH plasma levels and this was expected as GH levels are known to have variation within ruminants. It appears that Fenugreek used as a natural feed additive can increase the milk yield from dairy goats, which would be beneficial to the commercial dairy goat farmer. However, the process on how Fenugreek exerts its effect on milk production still remains unclear. / AFRIKAANSE OPSOMMING: Tot datum is min navorsing gepubliseer wat die invloed van natuurlike voer bymiddels op melkproduksie aanspreek. Fenugreek (Trigonella foenumgraecum) is ‘n peulgewas en kom voor in Indië, die Midde Ooste, Noord Afrika en Suid Europa. Fenugreek word in tradisionele medisyne gebruik om sodoende melkproduksie in lakterende vroue te verhoog. Dit verhoog ook melkprodukise in melkkoeie, waterbuffels en melkbokke. Diocin is ‘n natuurlike saponien, met sterk oestrogeniese strukturele ooreenkomste, wat in Fenugreek voorkom. Diocin lei tot die verhoogde afskeiding van groeihormoon (GH) en uiteindelik ‘n toename in melkproduksie. Drie proewe is uitgevoer ten einde die effek van Fenugreek te ondersoek. Elke proef het bestaan uit drie behandelingsgroepe en melkbokke is ewekansig aan die groepe toegedeel. Nutrifen®, NutrifenPlus® en ‘n kontrole sonder enige additief is gebruik as behandelings. Agt-en-veertig bokke is per behandeling gebruik in die eerste proef. Die doel van hierdie proef was om die invloed van Fenugreek op melkproduksie en melksamestelling te bepaal. Die tweede proef het agt bokke per behandelingsgroep gehad en het ten doel gehad om te bepaal wat die invloed van Fenugreek op die in vitro en in vivo verteerbaarheid van die voere was. In die derde proef is dieselfde bokke as die in proef twee gebruik en hier is groeihormoon vlakke in sirkulerende bloedplasma gemeet om die invloed van Fenugreek op hierdie parameter te bepaal. Resultate van die eerste proef het getoon dat melkproduksie van bokke wat Nutrifen® ontvang het betekenisvol verhoog het (P = 0.01) terwyl NutrifenPlus® gelei het tot ‘n verhoging (P = 0.03) in melk laktose vlakke. Bloed cholesterol en melk cholesterol vlakke was onveranderd. Skynbare verteerbaarheid van die totale verteerbare voedingstowwe (TVV) van die voer het nie verander (P = 0.34) met die insluiting van Fenugreek nie. Plasma groeihormoonvlakke was nie betekenisvol verskillend (P > 0.05) tussen behandelingsgroepe nie en die gebrek aan verskille kan waarskynlik toegeskryf word aan die variasie wat binne behandelings groepe opgemerk is vir hierdie parameter. Sodanige variasie in plasma groeihormoon word as algemeen beskou in herkouers. Gevolglik kan aanvaar word dat die natuurlike voerbymiddel, Fenugreek, gebruik kan word om melkproduksie in lakterende melkbokke te verhoog. Hierdie praktyk behoort voordele in te hou vir die kommersiële melkprodusent. Die proses waardeur hierdie verhoging plaasvind is egter steeds nie duidelik nie.

Five experiments were conducted to evaluate tree forage as a feedstuff for small livestock, using the foliage of black locust (Robinia pseudoacacia) and hybrid poplar (Populus spp.). In the first trial, rabbits were fed diets containing 40% alfalfa (control), and 10%, 20% and 40% poplar leaves (PL) from untrimmed or uncoppiced growth, and 10% and 20% PL from trimmed or coppiced growth. At the 20% level, crude protein (CP) was better digested for the coppiced PL than for the uncoppiced (p < .05). No significant difference was evident between treatments in the average daily gain (ADG) or feed efficiency, but dry matter (DM) intake increased for all the PL treatments compared to the control (p < .01). In the second experiment, black locust (BL) leaves were treated by various methods in an attempt to counter the effect of tannins. Rabbits were fed diets containing 50% alfalfa (control), 25% alfalfa and 25% black locust meal (BLM) (BLM control), BLM + 1% polyethylene glycol (PEG), BLM + 1% phytase, and BLM + 0.3% L-methionine and 0.3% choline chloride. In general, nutrient utilization and ADG were better for the control than for the BLM treatments. The addition of PEG increased CP digestibility (p < .01) and ADF (p < .03) compared to the BLM control, partially alleviating the reduced nutrient availability. The addition of L-methionine and choline chloride increased ADF digestibility (p < .02). In the third trial, black locust (BL) bark and other tree products were used to study the possible toxic effects of lectins in BL bark. Rabbits were fed diets containing 25% BL bark, oak sawdust, red alder bark, or red alder sawdust (all diets also included 25% alfalfa). A 50% alfalfa diet served as a control. In general, nutrient digestibilities and ADG were higher for the control than the treatments and, also, higher for the BL bark diet than the alder bark diet. The ADG with the BL bark diet was lower than for the alder bark diet (p < .01), which indicated a possible toxic effect of the BL bark. The fourth trial examined the feeding value of poplar leaves for sheep. Sheep were fed diets containing 50% PL or 50% alfalfa. Nutrient digestibilities were lower for the PL diet (p < .01). In the fifth experiment, BL leaves were fed to sheep and goats in order to determine if goats, being browsers instead of grazers like the sheep, are better equipped to tolerate the anti-nutritive effects from BL forage. Sheep and goats were fed diets composed solely of BL leaves or alfalfa (control). Overall, the nutrient digestibilities were higher for alfalfa than for BL leaves, and there was no difference in terms of digestibility between species. Although the leaves of black locust and poplar contain anti-nutritive factors, it was concluded that the trees have potential as multipurpose trees from which the leaves could be harvested as animal fodder, particularly in temperate areas of the developing world. / Graduation date: 1993

This study was conducted to determine the effects of different levels of dietary tannin on the physiology of Boer goats. In particular, dietary intake, digestibility, gastrointestinal tract (GIT) histology and presence of bacteria along the GIT were measured. In addition the ability of goats to detoxify tannins by measuring liver and kidney mass; and urinary glucuronic acid concentration was investigated. Commercialized tannin was used because of wide variation of tannin levels, which can be affected by season, species, and part of the plant. Thirty adult, male goats were fed one of five diet treatments of different tannin levels (0%, 5%, 10%, 15% and 20%) for 6 weeks following which they were kept in metabolic crates for data collection for a further 10 days. Dietary intake of feed decreased significantly as tannin levels increased between the diets. Digestibility of dry matter (DM) tended to decrease with increasing tannin levels. However, digestibility of crude proteins (CP), organic matter, neutral detergent fibre and acid neutral detergent fibre decreased Significantly with increasing tannin levels. Faecal CP increased while urinary CP decreased with increasing tannin levels. There was no tannin present in the faeces. It appears that goats cope with low levels of tannin ingestion. There appears to be a threshold above which greater tannin ingestion has detrimental effects. The linear decreased dietary intake with increased tannin level may indicate that goats limit their intake of tannin below some threshold as a defence strategy. Differences in the histopathology of the oesophagus, reticulum, rumen, abomasum and duodenum were evaluated. Animals on the control diet had more protozoa present in the GIT than the other diets. Number and types of bacteria observed in the reticulum and rumen increased with tannin level in the diet. These may be responsible for tannin-protein complex degradation. Few bacteria were observed in the abomasum. There was a loss of epithelial cells and erosion of microvilli in duodenum with increased tannin levels, which would impair absorption of nutrients. The width of the keratinized GIT epithelial layer increased and villi height decreased as tannin levels increased which could further reduce nutrient absorption. Goats in the present study did not show detoxification abilities because the liver and kidney masses, and urinary glucuronic acid concentration did not increase with increased dietary tannin levels In summary, condensed tannins as large compounds appear to be metabolized and absorbed from the GIT. However, it is not clear if they are detoxified at the epithelial mucosa interface. The main detrimental effect of tannin on goats appears to be the reduction of feed intake and increased faecal CP. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Small maize livestock farmers in the Eastern Province of Zambia badly need forage high in protein to supplement the protein deficient pasture grass. Nutrient intake, especially for the small ruminants with small gastro-intestinal capacity compared to metabolizable energy requirement, will be near or below maintenance if these poor quality feeds are not supplemented. High quality supplements however, are beyond the reach of the small scale farmers. The effect of feeding maize husk and leucaena as a mixture or separately on voluntary intake of maize husk was studied over a 40 day period. Ten male goats with an average weight of 15 kg were used. In a separate experiment the effect of browse supplementation on maize husk utilization by goats was studied. The treatments were; maize husk plus urea; maize husk plus Leucaena leucocephala (3:2); maize husk plus Calliandra calothyrsus (3:2); and maize husk plus leucaena plus calliandra (3:1:1). The results of the study indicate that leucaena and calliandra are both potentially valuable feed components.

Orientador: Izabelle Auxiliadora Molina de Almeida Teixeira / Banca: Gustavo Rezende Siqueira / Banca: Antonello Cannas / Banca: Gilberto de Lima Macedo Junior / Banca: Renata Helena Branco Arnandes / Resumo: O objetivo principal foi determinar a contribuição dos diferentes segmentos do trato gastrointestinal (TGI) para a digestão da fibra. Dois experimentos foram conduzidos, os quais foram determinados o tempo médio de retenção (TMR) de partículas e líquido, conteúdo e pesos dos tecidos nos diferentes segmentos pelo método do abate. O primeiro estudo avaliou TMR de partículas e líquido de cabritos Saanen em crescimento de diferentes sexos e submetidos a diferentes níveis de restrição alimentar. Foram utilizados 54 cabritos da raça Saanen (18 fêmeas, 18 machos castrados e 18 machos inteiros) em um arranjo fatorial 3 × 3 que compreendeu os três sexos e três níveis de restrição alimentar (ad libitum / sem restrição, restrição moderada e severa). Contrastes polinomiais foram utilizados para determinar o efeito linear e quadrático da restrição alimentar, enquanto o efeito do sexo foi comparado pelo teste de Tukey. Os efeitos do sexo e interação entre sexo e restrição alimentar não foram significativos na maioria das variáveis avaliadas. A restrição alimentar aumentou o TMR de partículas e fluído. O TMR foi um recurso importante para aumentar a oferta de nutrientes, quando os animais foram submetidos à restrição alimentar, como indicado pelo aumento da digestibilidade total. O segundo estudo avaliou aspectos fisiológicos da digestão da fibra, retenção de partículas e líquido, conteúdo e peso dos tecidos em todo o TGI de cabritos da raça Saanen. O total de 58 cabritos da raça Saanen foram aleatoriamente dispostos em um arranjo fatorial 3 × 3, composto por três sexos (fêmeas, machos castrados, machos inteiros) e três pesos de abate (aproximadamente 16, 23, e 30 kg de peso no abate). Os efeitos do tratamento foram avaliados em um esquema de parcelas subdivididas, com o sexo como efeito principal e peso de abate como sub parcela. Contrastes polinomiais foram utilizados para determinar os efeitos ... / Abstract: The main objective was to assess the contribution of different segments of the gastrointestinal tract (GIT) to the fiber digestion. Two experiments were conducted, which mean retention time (MRT) of particulate and liquid matter, pool size, and tissues weight in different segments were determined by slaughter technique. The study one evaluated MRT of particulate and liquid matter in growing Saanen goats of different sexes and subjected to different levels of feed restriction. Fifty-four Saanen goats (18 each of females, castrated males and intact males) were used in a 3×3 factorial arrangement comprising the three sexes and three levels of feed restriction (unrestricted/ad libitum, moderate and severe restriction). Polynomial contrasts were used to determine linear and quadratic effect of feed restriction, while the effect of sex was compared by Tukey test. The effects of sex and the interaction between sex and feed restriction were not significant on most of variables evaluated. In conclusion, the level of feed restriction increased the MRT of particulate and liquid matter. The MRT was an important mechanism to increase nutrient supply when animals were subjected to feed restriction, as indicated by increased total tract digestibility. The second study examined physiological aspects in the digestion of fiber, particulate and liquid matter residence, pool size, and tissues weight in the whole tract of growing Saanen goats. A total of 58 Saanen goats were disposed in a 3×3 factorial arrangement consisting of three sexes (female, castrated males, intact males) and three slaughter weights (target BW 16, 23, and 30 kg at slaughter). Treatment effects were evaluated in a split-plot design, with sex as the main plot and slaughter weight as the subplot. Polynomial contrasts were used to determine linear and quadratic effects of slaughter weight. Thus increased BW at slaughter resulted in greater MRT of particulate and liquid matter in ... / Doutor