Typescript (photocopy). / Digitized by Kansas Correctional Industries

Two silages were prepared from mature orchardgrass ensiled at 19% dry matter. The additive NutroLac Sila-Aid, containing a dry culture, of lactobacilli, was added to one silage at a rate of 0.5 kg per tonne of fresh herbage, the other silage remained untreated. A wooden stave silo of 40-tonne capacity was filled with each silage. Silage effluent was collected daily for 30 days and the silage temperature was recorded daily for 2.5 months. These two silages comprised the only forage in a two-period crossover design feeding trial. The silages were fed ad libitum (10% feed refusal) and grain was fed at a rate of 1 kg per 3.5 kg milk yield. Twelve Holstein cows in early to mid lactation were subdivided in two groups and allocated to the treated or untreated silage. The cows were fed the assigned forage for a 7-day adjustment period and a 7-week experimental period. The treatments were reversed during a 7-day change-over period and the alternate forage fed for a further 6 weeks. Three cows from each group were assigned to a 7-day digestion trial for total collection of feces and urine during the second last week of each experimental period. The herbage ensiled had the same composition for both silos, the dry matter and protein contents being 19.0 and 14.4% respectively. The treated silage lost almost twice as much effluent compared to the control. Dry matter and protein loss accounted for 2.5 and 4.2% of the ensiled dry matter and protein in the treated silage and 1.5 and 2.3% in the control silage. Peak silage temperatures of 30.3 and 29.1°C for treated and untreated silage were recorded on the ninth day after ensiling. The resulting silage had a dry matter and protein content of 22.8 and 13.2% (treated) and 23.8 and 13.0% (untreated). There was no significant difference (P^.05) between the two treatments with regards to intake, body weight change and milk production. On the average the cows consumed 10.1 kg forage and 8.0 kg grain on a dry matter basis and yielded 2 28.0 kg milk containing 3.2% fat. The animals fed NutroLac silage gained an average of 3.7 kg per period whereas the cows on control silage lost 5.6 kg over the same time. The rumen pH and the acetate/propionate ratio of the ruminal fluid was the same for both treatments, the values being 6.6 and 2.4. The apparent dry matter digestibility of the total ration was significantly higher (P≤.05) for the control silage (70.7%) compared to the treated (69.1). The digestibility of organic matter and protein was not different (P≤.05) between treatments, the average being 7 3.3 and 74.4%. The results from the present experiment tended to be in favour of the control silage and indicated that there was no advantage, and perhaps even a disadvantage, in terms of dry matter digestibility and increased ensiling losses when NutroLac was added to the grass at ensiling time. / Land and Food Systems, Faculty of / Unknown

The objective of this study was the evaluation of grass silage made from P. maximum cv. Gatton (P. maximum) and Digitaria eriantha spp. eriantha (Smutsfinger) grass. The study was conducted in two phases. In phase one the influence of sugar (molasses) addition, wilting, growth stage and plant species, on the quality of the silages obtained, were investigated. Three growth stages were incorporated, an early (physiologically young), medium (boot) and late (full bloom) stage. Four different treatments were applied during ensiling, namely direct cut, direct cut + sugar, wilted and wilted + sugar. The second phase comprised of a partial digestibility study to evaluate the differences between plant species and growth stage, within a specific treatment. The silages used were made from the medium and late growth stages, where prior wilting and sugar addition occurred. The addition of sugar during ensiling, even with prior wilting, had a positive effect on silage quality, leading to a lower pH, ammonia-nitrogen concentration and a higher lactic acid concentration in the silage. These effects were less pronounced with the plant material ensiled at a late growth stage. These silages tended to undergo secondary fermentation between day 21 and day 120, when sugar was added. When comparing the three growth stages, within the direct cut + sugar and wilted + sugar treatments, the following was observed. The silages made from early and medium growth stages tended to be of better quality compared to the silages made from the late growth stage. In most of the comparisons the silages made from the medium growth stage were of a better quality than that of the silages made from the younger plant material. In the comparison between P. maximum and D. eriantha silages, the silages made from P. maximum grass tended to be of a better quality than that made from D. eriantha grass. The difference between the two species was smaller than the differences observed between growth stages within a specie. In the partial digestibility study, there was a difference in OMI, with sheep receiving the late growth stage silages having higher intakes. When expressed as DOMI / W0.75 no significant differences were observed between the four diets. There were no significant differences in the total digestibility of OM across the four diets. There were differences in the rumen ammonia and VFA's concentrations across the diets. There was a significant difference in the intake of nitrogen across the four diets, resulting in differences in the disappearance of nitrogen, ammonia and non-ammonia-nitrogen across the four diets. There was no difference in the total true nitrogen digestibility across the four diets. / Dissertation (MSc Agric (Animal Nutrition))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted

Research was conducted in Sri Lanka to study the effects of growth stage, chopping length and additives on ensiling characteristics of Guinea-'A' (Panicum maximum - Ecotype-'A') and NB-21 (Pennisetum purpureum Schumac x Pennisetum americanum). The forages were harvested 1, 2 and 3 wk after growth, chopped and ensiled in small laboratory silos (3 liter cardboard cylinders double lined with polyethylene bags) alone or with additions of cassava tuber meal, coconut oil meal and formic acid. Cutting grass at 1 wk increased (P<.05) acetic and lactic acid of silage, compared to 3 wk. Addition of cassava tuber meal and coconut oil meal increased (P<.05) lactic acid and decreased (P<.05) pH and acetic acid of silage, compared with the control. The effects were greater for cassava tuber meal. In a second study 3-wk growth of Guinea-'A' grass was hand chopped to 1.5, 7.5 and 15 cm, and ensiled in small laboratory silos. Lactic and acetic acid of silage increased (P<.01), whereas dry matter loss and pH decreased (P<.05) with fineness of chop. In a third study, 2 and 3 wk growths of Guinea-'A' were harvested and ensiled in 210 liter metal drums, double lined with polyethylene bags, chopped or unchopped. Cutting grass at 2 wk decreased (P<.05) pH and increased (P<.01) lactic acid, compared to 3 wk. Chopping decreased (P<.05) the pH and increased (P<.05) lactic acid and acetic acid of silage. Experiments were also conducted to study the digestibility and palatability by sheep of Guinea-'A' silage prepared in the third study. Apparent digestibility of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were higher (P<.01) for 2 wk compared to 3-wk growth. Chopping the grass before ensiling increased (P<.01) the apparent digestibility of DM, CP, NDF, ADF and hemicellulose. No significant differences were observed for DM intake by sheep due to the growth stage, but chopping increased (P<.01) DM intake by 17%. Lengthening the cutting interval of Guinea-'A' and NB-21 resulted in linear increases (P<.01) in DM yield. / Ph. D.

162 leaves printed on single pages, preliminary pages i- vii and numbered pages 1-152. Includes bibliography and abbreviations. / Digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner. / Thesis (PhD(Agric))--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Maize, forage sorghum, lucerne, oats, barley and triticale are the most common silage crops in South Africa, while tropical grasses like Eragrostis curvula and Digitaria eriantha are ensiled to a lesser extent. The aim of this study was to determine the effect of adding a lactic acid bacterial inoculant to E. curvula, D. eriantha, lucerne, forage sorghum, maize and oat silage. The effect of the addition of a lactic acid bacterial inoculant when ensiling E. curvula on the fermentation dynamics during ensiling and the aerobic stability of the silage was determined. The addition of the lactic acid bacterial inoculant to E. curvula at ensiling resulted in a more rapid lowering in pH and improved preservation. Inoculated silage had a higher lactic acid content, less protein breakdown and a lower butyric acid content compared to that of the control silage. Both silages were stable when exposed to air for five days. Digitaria eriantha was ensiled, with or without the addition of a lactic acid bacterial inoculant containing Lactobacillus plantarum. Streptococcus faecium and Pediococcus acidilactici together with the enzymes, cellulase, hemicellulase and amylase. The addition of the inoculant resulted in a more rapid drop in pH, a higher level of lactic acid, an increase in the number of lactic acid bacteria, less protein breakdown and lower numbers of enterobacteria, clostridial spores, yeast and mould compared to the control silage. Digitaria eriantha hay, control and inoculated silage diets were fed to 24 Merino rams (n = 8 per treatment) to determine intake and digestibility. The intake of diets consisting of 90.9% D. eriantha hay, control silage or inoculated silage, differed significantly (p<0.05) at 1395, 1540 and 1848 g DM/day, respectively. The in vivo organic matter digestibility (glkg) of D. eriantha hay, untreated silage and inoculated silage diets was 561, 546, 574, respectively. The addition of the bacterial inoculant when ensiling D.eriantha resulted in better preservation, improved aerobic stability, as well as a higher in vivo organic matter digestibility and intake of D. eriantha silage. The addition of an inoculant or molasses to lucerne (Medicago sativa), ensiled in laboratory silos was investigated. The addition of the additives resulted in an increased preservation rate as indicated by a more rapid lowering of pH, a faster rate of lactic acid production and less protein breakdown compared to control silage. The inoculant was more effective than the molasses in improving the rate of preservation. The aerobic stability of lucerne silage was not affected by inoculation or the addition of molasses. The addition of an inoculant to wilted big bale lucerne silage was studied. The inoculant improved silage quality as indicated by a lower pH, higher lactic acid content, lower ammonia nitrogen content and lower level of butyric acid in inoculated silage compared to the control lucerne silage. The composition of big round bale lucerne silage differed markedly from that of lucerne ensiled in laboratory silos as the former had a higher pH, ammonia nitrogen, butyric acid and acetic acid content and a lower lactic content. Whole crop forage sorghum cultivar FS2 was harvested at the late bloom (20.7% DM) and soft dough (28.9% DM) stages of maturity and ensiled in laboratory silos with the addition of commercial silage inoculants. At both stages of maturity the inoculants caused a more rapid rate of pH decline and a higher amount of lactic acid production. All the silages were well preserved. Silages of the sorghum ensiled at the late bloom stage with all treatments were stable after 5 days of aerobic exposure, whereas sorghum ensiled at the soft dough stage with the addition of the inoculants deteriorated upon aerobic exposure. It is concluded that addition of lactic acid bacterial inoculants to mature sorghum at ensiling might impair the aerobic stability of the silage. The yield, nutritional value and production potential of silage made from twenty one maize hybrids was compared. It was concluded that maize hybrids did differ in metabolizable energy content, rate of digestion, predicted intake and predicted milk production potential. The content of NDF and ADF did not differ between the maize hybrids used in this study and could therefore not be used to predict nutritional value or production potential. Maize was harvested at the hard dough stage and ensiled with or without the addition of a lactic acid bacterial inoculant in laboratory silos and in 210 litre drums. The adding of the inoculant to maize at ensiling did not result in a more rapid drop in pH and higher levels of lactic acid. The intake and growth of South African Mutton Merino lambs fed inoculated and untreated maize silage diets was determined. The average daily gain of lambs fed a diet consisting of either 60% control or inoculated maize silage over a growth period of 60 days was 239 ± 26 and 255 ± 44 g/day, respectively. Although the laboratory study showed very little effect of adding a lactic acid bacterial inoculant to maize at ensiling, lambs tended to consume more of the inoculated silage. In the second study the effect of the addition of a lactic acid bacterial inoculant with an enzyme to maize at ensiling on the fermentation dynamics during ensiling, aerobic stability of the silage, the intake, milk production and milk composition of Jersey cows fed maize silage diets was determined. The inoculant did not result in a more rapid lowering of the pH or a more rapid lactic acid production compared to untreated maize silage made in laboratory silos. Both the control and inoculated maize silages were well preserved. The addition of the inoculant to maize at ensiling improved the palatability, intake and the aerobic stability of maize silage compared to the untreated control maize silage. Milk production, milk composition, live weight and condition score of Jersey cows was not significantly affected by the addition of the inoculant to maize silage. The effect of the addition of an enzyme containing lactic acid bacterial inoculant to big bale oat (Avena sativa, cv Cederberg) silage on silage composition, silage intake, milk production and milk composition of Jersey cows was determined. The crop was cut at the bloom stage, wilted and ensiled in big round bales. The inoculant, Sil-All, was applied during the baling process on half of the bales. Silages were fed to Jersey cows in an intake and milk production study. Both the control and inoculated oat silages were well preserved. The inoculated oat silage had a lower level of butyric acid than the control oat silage. Cows fed the inoculated oat silage produced more (P=O.05) milk (17.7 kg/day) than cows fed the control oat silage (16.7 kg/day). The addition of a lactic acid bacterial inoculant to big bale oat silage improved silage composition and animal performance. This study clearly showed that the composition of silages made in bunker silos under commercial farm conditions differ largely from that of silages made in small scale laboratory silos. When the effect of silage additives on aerobic stability of silage is determined the evaluation should include studies on large scale bunker silages. Evaluation of silage additives should include intake and animal production studies. / AFRIKAANSE OPSOMMING: Mielies, voersorghum, lusem, hawer, gars en korog word algemeen as kuilvoer gewasse benut terwyl tropiese grasse soos Eragrostis curvula en Digitaria eriantha tot 'n mindere mate ingekuil word. Die doel van hierdie studie was om die invloed van 'n melksuurbakterieseinokulant op E. curvula-, D. eriantha-, lusem-, voersorghum-, mielie- en hawerkuilvoer te bepaal. Die invloed van 'n melksuurbakteriese-inokulant op die fermentasiedinamika en die aerobiese stabiliteit van E. curvula-kuilvoer is bepaal. Die toediening van die melksuurbakterieseinokulant tot E. curvula tydens inkuiling het 'n vinniger tempo van pH daling en beter preservering tot gevolg gehad in vergelyking met kontrole kuilvoer. Inokulant behandelde kuilvoer het 'n hoer melksuurinhoud, minder protei'en afbraak en 'n laer bottersuurinhoud as kontrole kuilvoer gehad. Beide kuilvoere was stabiel tydens blootstelling aan lug vir vyf dae. Digitaria eriantha is ingekuil met ofsonder die toediening van 'n melksuurbakteriese-inokulant wat Lactobacillus plantarum. Streptococcus faecium en Pediococcus acidilactici sowel as die ensieme, sellulase, hemisellulase and amilase bevat het. Die inokulant het 'n vinniger tempo van pH-daling, hoer vlakke van melksuur en melksuurbakterie, minder protei'en afbraak en laer getalle van enterobakterie, klostridiale spore, giste and swamme in vergelyking met die kontrole tot gevolg gehad. Digitaria eriantha hooi, kontrole kuilvoer en gei'nokuleerde kuilvoer diete is aan 24 Merino ramme (n = 8 per behandeling) gevoer vir bepaling van inname en verteerbaarheid. Die inname van diete wat uit 90.9% D. eriantha hooi, kontrole kuilvoer of gei'nokuleerde kuilvoer bestaan het, het betekenisvol (p<0.05) verskil en was 1395, 1540 en 1848 gDM/dag, respektiewelik. Die in vivo organiesemateriaal verteerbaarheid (gIkg) vanD. eriantha hooi, kontrole kuilvoer en geYnokuleerde kuilvoer was 561, 546, 574, respektiewelik. Die toediening van die bakteriese-inokulant tydens inkuiling vanD. eriantha het beter preservering, verbeterde aerobiese stabiliteit asook 'n hoer in vivo organiesemateriaal verteerbaarheid van D. eriantha kuilvoer tot gevolg gehad. Die effek van toediening van 'n melksuurbakteriese-inokulant en van molasse tot lusem (Medicago sativa) ingekuil in laboratoriumsilos is ondersoek. Die inokulant toediening en molasse toediening het die tempo van preservering versnel, die pH het vinniger gedaal, melksuur is teen 'n hoer tempo geproduseer en minder proteYen afbraak het plaasgevind in vergelyking met die kontrole kuilvoer. Die tempo van preservering is meer effektief deur toediening van die inokulant verhoog as deur die toediening van molasse. Die aerobiese stabiliteit van lusernkuilvoer is nie beYnvloed deur die toediening van inokulant ofmolasse nie. Die effek van die toediening van 'n melksuurbakteriese-inokulant tot groot rondebaal lusernkuilvoer is ondersoek. Die inokulant het die kwaliteit van die kuilvoer verbeter en het 'n laer pH, hoer melksuur, laer ammoniak stikstofen laer bottersuurinhoud in rondebaallusernkuilvoer tot gevolg gehad in vergelyking met kontrole kuilvoer. Groot rondebaallusernkuilvoer het grootliks verskil van lusernkuilvoer wat in laboratoriumsilos ingekuil is. Die rondebaal kuilvoer het 'n hoer pH, hoer ammoniak-stikstof-, bottersuur- en asynsuurinhoud en 'n laer melksuurinhoud gehad as laboratorium lusernkuilvoer. Voersorghum kultivar FS2 is op die laat blom (20.7% DM) en op die sagte deeg (28.9% DM) stadium met die byvoeging van melksuurbakteriese-inokulante ingekuil in laboratoriumsilos. Toediening van beide inokulante tot sorghum hetop beide die inkuilstadiums gelei tot 'n vinniger tempo van pHdaling en meer melksuurproduksie. Aile kuilvoere insluitend die kontrole kuilvoer was goed gepreserveer. Kontrole sowel geYnokuleerde sorghumkuilvoer ingekuil op die laat blomstadium was stabiel tydens aerobiese blootstelling vir 5 dae. Sorghumkuilvoer ingekuil op die sagtedeegstadium met die byvoeging van inokulante was onstabiel tydens aerobiese blootstelling. Die toediening van melksuurbakteriese-inokulante tot sorghum wat op die sagtedeegstadium ingekuil word kan aerobiese stabiliteit van die kuilvoer grootliks benadeel. Die opbrengs, voedingswaarde en produksiepotensiaal van kuilvoer gemaak van 21 mielie hibriede is vergelyk. Verskille in metaboliseerbare energie inhoud, tempo van vertering, voorspelde inname en voorspelde melkproduksie het tussen mielie hibriede voorgekom. Die neutraalbestandevesel- en suurbestandeveselinhoud het nie verskil tussen hibriede nie en derhalwe kon dit nie gebruik word om voedingswaarde ofproduksiepotensiaal te beraam rue. Mielies is op die hardedeegstadium met of sonder die toediening van 'n melksuurbakterieseinokulant in laboratoriumsilos en 210 liter dromme ingekui!. Die toediening van die inokulant het geen invloed op tempo van pH-daling ofproduksie van melksuur gehad nie. Die inname en groei van SA Vleismerino lammers wat 'n dieet bestaande uit 60% kontrole of inokulant behandelde mieliekuilvoer ontvang het, is bepaa!. Die gemiddelde daaglikse toename van lammers was 239 ± 26 and 255 ± 44 g/dag vir die kontrole en inokulant mieliekuilvoer dieet respektiewelik. Alhoewel die laboratoriumstudie weinig verskille tussen die kontrole en die geYnokuleerde mieliekuilvoer getoon het, het lammers geneig om meer van die geYnokuleerde mieliekuilvoer in te neem. In die tweede studie met mieliekuilvoer is die effek van toediening van 'n melksuurbakteriese-inokulant met ensieme, op die ferrnentasiedinamika tydens inkuiling, die aerobiese stabiliteit van mieliekuilvoer asook die inname, melkproduksie en melksamestelling van Jersey koeie bepaa!. Die inokulant het nie die tempo van pH daling en produksie van melksuurverhoog nie en beide kontrole en geYnokuleerde mieliekuilvoerwas goed gepreserveer. Die toediening van die inokulant tot mieliekuilvoer het die smaaklikheid, inname en die aerobiese stabiliteit van mieliekuilvoer verhoog in vergeiyking met kontrole mieliekuilvoer. Melkproduksie, melksamestelling, liggaamsmassa en kondisiepunt van Jersey koeie is nie betekenisvol beYnvloed deur die toediening van die inokulant tot mieliekuilvoer nie. Die effek van die toediening van 'n ensiem bevattende melksuurbakteriese-inokulant tot groot rondebaal hawer (Avena sativa, cv Cederberg) kuilvoer op die samestelling van kuilvoer, kuilvoerinname, melkproduksie en melksamestelling van Jersey koeie is bepaa!. Die gewas is gesny op die blomstadium, verwelk en as rondebaalkuilvoer gepreserveer. Die inokulant, Sil-All, is tydens die baalproses toegedien op die helfte van die bale. Kuilvoere is aan Jersey koeie gevoer in 'n inname en melkproduksiestudie. Beide die kontrole en geYnokuleerde hawerkuilvoer was goed gepreserveer. Die bottersuurinhoud van geYnokuleerde hawerkuilvoer was laer as die van die kontrole hawerkuilvoer. Koeie wat geYnokuleerde hawerkuilvoer gevoer is het meer (P=0.05) melk (17.7 kg/dag) geproduseer as koeie wat kontrole hawerkuilvoer ontvang het (16.7 kg/dag). Die toediening van 'n melksuurbakteriese-inokulant het kuilvoer kwaliteit en diereproduksie verbeter. Hierdie studie wys duidelike verskille uit tussen kuilvoer wat in bunkersilos onder kommersiele toestande ingekuil is, en kuilvoer wat in laboratoriumsilos gemaak is. Wanneer die effek van kuilvoerbymiddels op die aerobiese stabiliteit van kuilvoer bepaal word behoort finale evaluasie gedoen te word op kuilvoer gemaak in bunkersilos soos onder plaastoestande plaasvind. Evaluasie van kuilvoerbymiddels behoort inname en diereproduksiestudies in te sluit.