LD2668 .T4 1962 M57

Call number: LD2668 .T4 1965 H47 / Master of Science

Na região Amazônica do Norte do Brasil, Panicum maximum cultivares Mombaça, Tanzânia e Massai causam cólica severa e morte durante o período chuvoso quando os pastos em brotação são pastejados pelos equídeos. Em oito surtos estudados, um total de 52 de 153 equídeos adoeceram e 19 morreram (10 mulas e 9 cavalos). Os sinais clínicos foram de cólica e dilatação abdominal e os sinais clínicos variaram de 12 horas a 4 dias. As atividades séricas de gama glutamiltransferase e aspartato aminotransferase estavam em níveis normais e os valores séricos de uréia e creatinina se mostravam elevados esporadicamente. Os principais achados macroscópicos e microscópicos observados foram no sistema digestivo. O estômago, intestino delgado e grosso apresentavam hemorragia severa, ulcerações e erosões da mucosa. Ao exame histológico foram observadas gastrite linfoplasmocitária difusa e enterite com congestão severa e hemorragias, e ocasionalmente necrose epitelial e ulceração. Necrose linfocítica do tecido linfóide associada ao intestino foi observada ocasionalmente. Nefrose tubular ocorreu em alguns animais. Em relação à etiologia da doença, nos estudos dos surtos foram pesquisadas três causas prováveis: intoxicação por saponinas contidas nas pastagens; intoxicação por esporidesmina produzida por Pithomyces chartarum; e intoxicação por cantaridina produzida por Epicauta spp. Os pastos foram negativos para as saponinas diosgenina e yamosgenina, os níveis de oxalato estavam dentro da normalidade para a espécie e não foram encontrados besouros do gênero Epicauta na pastagem. Foram realizados 3 experimentos com Panicum maximum cv. Mombaça em brotação. No experimento 1, realizado na época de seca, dez animais receberam no cocho durante 40 dias o capim em brotação recém cortado sem adoecer. No experimento 2, realizado na época de chuvas, outros 10 animais receberam capim recém cortado em brotação no cocho. Adoeceram dois animais, um no 5º dia e outro no 11º dia de experimento com sinais clínicos de cólica sendo retirados do experimento. No experimento 3, também durante a época de chuvas, com o capim em brotação, os mesmos 10 animais foram separados em dois grupos de 5, um grupo recebia capim recém cortado e o outro recebia o capim cortado, dessecado à sombra durante 24 horas antes da administração. No experimento 3, no grupo que recebia o capim coletado com 24 horas de antecedência, um animal adoeceu no 13º dia de experimento e também foi retirado do experimento. Foram realizadas análises bromatológicas nas amostras de P. maximum cv. Mombaça e Tanzânia aos 15, 30, 45 e 60 dias de crescimento vegetativo para verificar os valores de carboidratos não fibrosos (CNF). Os valores médios de CNF encontrados nas 36 amostras das pastagens aos 15, 30, 45 e 60 dias foram de 19,15, 19,36, 10,61 e 12,90%, respectivamente. Esses valores são mais do que o dobro do observado em pastagens de P. maximum em outras regiões do Brasil, indicando que as cólicas causadas por P. maximum na região Amazônica poderiam estar ligadas à grande concentração de CNF durante a época de chuvas, causando distúrbios fermentativos, com produção de gás e cólicas. / In the Amazon region of northern Brazil, Panicum maximum cultivars Mombaça, Tanzania, and Massai cause severe colic and death in horses and mules. The disease occurs in the rainy season, when sprouting pastures are grazed by equidae. In the 8 separate disease outbreaks studied, a total of 52 out of 153 equidae were affected, including 19 that died (10 mules and 9 horses). Clinical signs were colic and abdominal dilatation, with a clinical manifestation period of 12 hr to 4 days. Serum activities of gamma-glutamyl transferase and aspartate aminotransferase were within reference intervals; however, serum urea nitrogen and creatinine concentrations were occasionally elevated. The primary gross and histologic lesions were observed in the digestive system. The stomach, small intestine, and large intestine had severe hemorrhages and mucosal erosions and ulcerations. Histologic examination revealed diffuse lymphoplasmacytic gastritis and enteritis with severe congestion, hemorrhage, and occasional epithelial necrosis and ulceration. Lymphocellular necrosis was occasionally observed within gut-associated lymphoid tissue. Tubular nephrosis occurred in some animals. In the outbreaks the toxic pastures were negative for diosgenin- and yamogenin-based saponins, and oxalate concentrations were within reference intervals for the species. Epicauta spp was not found in the pastures. Three experiments were performed with growing Panicum maximum cv. Mombaça in penned horses. In Experiment 1, performed during the dry season, 10 horses were fed with sprouting P. maximum immediately after collection during 40 days, without showing clinical signs. In Experiment 2, performed during the raining season, other 10 horses were fed with recently harvested sprouting P. maximum. Two horses showed colic on the 5th and 11th days after the start of the ingestion. The other animals showed dilated abdomen due to gas production. In Experiment 3, also during the raining season the same 10 horses used in experiment 2 were divided in two groups of 5 horses each. Group 1 received P. maximum immediately after harvesting, and Group 2 received the Grass 24 hours after harvesting. One horse from group 2 showed colic on day 13th after the start of feeding. Nutritional analysis was performed in pastures of P. maximum cv Tanzania causing colic and in the pastures of P. maximum cv Mombaça used for Experiments 2 and 3. The pastures were examined at the start of the raining season, 15, 30, 45, and 60 days after been cut. Mean concentrations of non structural carbohydrates (NSC) in 36 samples at 15, 30, 45 and 60 days of regrowth were 19.15%, 19.36%, 10.61% and 12,9%, respectively. The concentrations of NSC at 15 days after cutting were more than twice the concentrations reported in other Brazilian regions, suggesting that colic in horses in P. maximum pastures, in the Northern (Amazon) region are due to high concentrations of non NSC during growing of the pastures on the raining season, causing a fermentative disturb followed by gas production, abdominal dilatation and colic.

Na região Amazônica do Norte do Brasil, Panicum maximum cultivares Mombaça, Tanzânia e Massai causam cólica severa e morte durante o período chuvoso quando os pastos em brotação são pastejados pelos equídeos. Em oito surtos estudados, um total de 52 de 153 equídeos adoeceram e 19 morreram (10 mulas e 9 cavalos). Os sinais clínicos foram de cólica e dilatação abdominal e os sinais clínicos variaram de 12 horas a 4 dias. As atividades séricas de gama glutamiltransferase e aspartato aminotransferase estavam em níveis normais e os valores séricos de uréia e creatinina se mostravam elevados esporadicamente. Os principais achados macroscópicos e microscópicos observados foram no sistema digestivo. O estômago, intestino delgado e grosso apresentavam hemorragia severa, ulcerações e erosões da mucosa. Ao exame histológico foram observadas gastrite linfoplasmocitária difusa e enterite com congestão severa e hemorragias, e ocasionalmente necrose epitelial e ulceração. Necrose linfocítica do tecido linfóide associada ao intestino foi observada ocasionalmente. Nefrose tubular ocorreu em alguns animais. Em relação à etiologia da doença, nos estudos dos surtos foram pesquisadas três causas prováveis: intoxicação por saponinas contidas nas pastagens; intoxicação por esporidesmina produzida por Pithomyces chartarum; e intoxicação por cantaridina produzida por Epicauta spp. Os pastos foram negativos para as saponinas diosgenina e yamosgenina, os níveis de oxalato estavam dentro da normalidade para a espécie e não foram encontrados besouros do gênero Epicauta na pastagem. Foram realizados 3 experimentos com Panicum maximum cv. Mombaça em brotação. No experimento 1, realizado na época de seca, dez animais receberam no cocho durante 40 dias o capim em brotação recém cortado sem adoecer. No experimento 2, realizado na época de chuvas, outros 10 animais receberam capim recém cortado em brotação no cocho. Adoeceram dois animais, um no 5º dia e outro no 11º dia de experimento com sinais clínicos de cólica sendo retirados do experimento. No experimento 3, também durante a época de chuvas, com o capim em brotação, os mesmos 10 animais foram separados em dois grupos de 5, um grupo recebia capim recém cortado e o outro recebia o capim cortado, dessecado à sombra durante 24 horas antes da administração. No experimento 3, no grupo que recebia o capim coletado com 24 horas de antecedência, um animal adoeceu no 13º dia de experimento e também foi retirado do experimento. Foram realizadas análises bromatológicas nas amostras de P. maximum cv. Mombaça e Tanzânia aos 15, 30, 45 e 60 dias de crescimento vegetativo para verificar os valores de carboidratos não fibrosos (CNF). Os valores médios de CNF encontrados nas 36 amostras das pastagens aos 15, 30, 45 e 60 dias foram de 19,15, 19,36, 10,61 e 12,90%, respectivamente. Esses valores são mais do que o dobro do observado em pastagens de P. maximum em outras regiões do Brasil, indicando que as cólicas causadas por P. maximum na região Amazônica poderiam estar ligadas à grande concentração de CNF durante a época de chuvas, causando distúrbios fermentativos, com produção de gás e cólicas. / In the Amazon region of northern Brazil, Panicum maximum cultivars Mombaça, Tanzania, and Massai cause severe colic and death in horses and mules. The disease occurs in the rainy season, when sprouting pastures are grazed by equidae. In the 8 separate disease outbreaks studied, a total of 52 out of 153 equidae were affected, including 19 that died (10 mules and 9 horses). Clinical signs were colic and abdominal dilatation, with a clinical manifestation period of 12 hr to 4 days. Serum activities of gamma-glutamyl transferase and aspartate aminotransferase were within reference intervals; however, serum urea nitrogen and creatinine concentrations were occasionally elevated. The primary gross and histologic lesions were observed in the digestive system. The stomach, small intestine, and large intestine had severe hemorrhages and mucosal erosions and ulcerations. Histologic examination revealed diffuse lymphoplasmacytic gastritis and enteritis with severe congestion, hemorrhage, and occasional epithelial necrosis and ulceration. Lymphocellular necrosis was occasionally observed within gut-associated lymphoid tissue. Tubular nephrosis occurred in some animals. In the outbreaks the toxic pastures were negative for diosgenin- and yamogenin-based saponins, and oxalate concentrations were within reference intervals for the species. Epicauta spp was not found in the pastures. Three experiments were performed with growing Panicum maximum cv. Mombaça in penned horses. In Experiment 1, performed during the dry season, 10 horses were fed with sprouting P. maximum immediately after collection during 40 days, without showing clinical signs. In Experiment 2, performed during the raining season, other 10 horses were fed with recently harvested sprouting P. maximum. Two horses showed colic on the 5th and 11th days after the start of the ingestion. The other animals showed dilated abdomen due to gas production. In Experiment 3, also during the raining season the same 10 horses used in experiment 2 were divided in two groups of 5 horses each. Group 1 received P. maximum immediately after harvesting, and Group 2 received the Grass 24 hours after harvesting. One horse from group 2 showed colic on day 13th after the start of feeding. Nutritional analysis was performed in pastures of P. maximum cv Tanzania causing colic and in the pastures of P. maximum cv Mombaça used for Experiments 2 and 3. The pastures were examined at the start of the raining season, 15, 30, 45, and 60 days after been cut. Mean concentrations of non structural carbohydrates (NSC) in 36 samples at 15, 30, 45 and 60 days of regrowth were 19.15%, 19.36%, 10.61% and 12,9%, respectively. The concentrations of NSC at 15 days after cutting were more than twice the concentrations reported in other Brazilian regions, suggesting that colic in horses in P. maximum pastures, in the Northern (Amazon) region are due to high concentrations of non NSC during growing of the pastures on the raining season, causing a fermentative disturb followed by gas production, abdominal dilatation and colic.

Grazing cattle on alfalfa (Medicago sativa L.) would be economically beneficial, but its rapid initial rate of protein degradation results in pasture bloat, low efficiency of protein utilization and excessive N pollution into the environment. Introducing a gene that stimulates the accumulation of mono/polymeric anthocyanidins might reduce the ruminal protein degradation rate and reduce bloat related foam stability. The overall objective of this thesis was to evaluate newly developed anthocyanidin-accumulating Lc-alfalfa progeny for nutritional properties (composition, site of degradation and molecular structure), environmental emissions and bloat characteristics. The objective of the first study was to determine survival and phytochemical and chemical profiles of Lc-alfalfa progeny (BeavLc1, RambLc3 and RangLc4) and their non-transgenic (NT) parental cultivars (Beaver, Rambler and Rangelander). Lc-alfalfa forage accumulated enhanced amounts of anthocyanidin, with an average concentration of 197.4 µg/g DM, while proanthocyanidin (i.e. condensed tannins) were not detected. Both of these metabolites were absent in the NT-parental varieties. Lc-alfalfa progeny had ~3 % less crude protein (CP) and ~3 % more carbohydrates (CHO), which resulted in their 11 g/kg lower N:CHO ratio compared with NT-alfalfa. Total rumen-degradable N:CHO ratio based on chemical analysis was 12.9 g/kg lower in Lc-alfalfa compared with NT-alfalfa. The objective of the second study was to evaluate in vitro degradation, fermentation and microbial-N partitioning of three forage color phenotypes [green, light purple-green (LPG) and purple-green (PG)] within Lc-progeny and their parental green NT-alfalfa varieties. Purple-green-Lc alfalfa accumulated more anthocyanidin than Green-Lc with LPG-Lc intermediate. Gas, methane and ammonia accumulation rates were slower for the two purple-Lc phenotypes compared with NT-alfalfa with Green-Lc intermediate. Effective degradable DM and N were lower in the three Lc-phenotypes compared with NT-alfalfa. Anthocyanidin concentration correlated negatively with gas and methane production rates and effective degradability of DM and N. The objectives of the third study were to evaluate in situ ruminal degradation characteristics and synchronization ratios, and to model protein availability to dairy cattle and net energy for lactation of three Lc-alfalfa progenies, BeavLc1, RambLc3 and RangLc4 and the cultivar AC Grazeland (selected for a low initial rate of ruminal degradation). Anthocyanidin accumulation was on average 163.4 ìg/g DM in the three Lc-progeny while AC Grazeland did not accumulate anthocyanidin. The basic chemical composition of the original samples, soluble and potentially degradable fractions and degradation characteristics of crude protein and carbohydrates were similar in Lc-alfalfa and AC Grazeland. The undegradable in situ crude protein and neutral detergent fiber fraction were, respectively, 1.3 %CP and 4.8 %CHO lower in the three Lc-progeny compared with AC Grazeland. Lc-alfalfa had a 0.34 MJ/kg DM higher net energy for lactation and tended to have a 11.9, 6.9 and 8.4 g/kg DM higher rumen degradable protein, rumen degraded protein balance and intestinal available protein, respectively, compared with AC Grazeland,. The hourly rumen degraded protein balance included an initial and substantial peak (over-supply) of protein relative to energy which was highest in RangLc4 and lowest in RambLc3. The hourly rumen degraded protein balance between 4 and 24 h was similar and more balanced for all four alfalfa populations. The objective of the fourth study was to determine foam formation and stability in vitro from aqueous leaf extracts of three Lc-alfalfa progeny (BeavLc1, RambLc3, RangLc4), parental NT-alfalfa and AC Grazeland (bloat reduced cultivar) harvested in the field at 07:00 or 18:00 h. Anthocyanidin accumulation averaged 247.5 ìg/g DM in the leaves of the three Lc-progeny. There was an interaction between population and harvest time for the foam parameters. Initial foam volume (0 min) and final foam volume (150 min) at 07:00 h were lower for AC Grazeland compared with all other treatments and lower for RangLc4 compared with the other two Lc-progeny at 0 min and NT-alfalfa at 150 min; while from the 18:00 h harvest, initial foam volume was larger for NT-alfalfa and final foam volume was larger for RambLc3 compared with AC Grazeland, BeavLc1 and RangLc4. Foam formation correlated positively (R = 0.30 to 0.44) with leaf DM content, leaf extract protein and ethanol-film content, spectroscopic vibration intensity due to all carbohydrates (CHOVI) and amide I:amide II ratio and negatively (R = -0.33 and -0.34; P<0.05) with á-helix:â-sheet ratio and amide I:CHOVI. Final foam volume correlated negatively (R = -0.53 to -0.25; P<0.05) with leaf extract pH, spectroscopic vibration intensity due to all protein structures, structural carbohydrates (SCVI) and lipids (CH2 and CH3 asymmetric stretching) and amide I:CHOVI ratio and corelated positively (R = 0.39 to 0.44; P<0.05) with CHOVI, amideI:SCVI ratio and CHOVI:SCVI ratio. In conclusion, all Lc-alfalfa progeny and phenotypes accumulated anthocyanidin in their forage. Lc-alfalfa progeny had lower protein and higher carbohydrate content which improved the nitrogen to carbohydrate balance compared to their parental NT-alfalfa cultivars. Rate of fermentation and effective degradability in vitro reduced for both purple anthocyanidin-accumulating Lc-alfalfa phenotypes compared with NT-alfalfa. Intestinal protein availability tended to be higher and net energy for lactation was higher from Lc-alfalfa progeny for dairy cattle compared with AC Grazeland. Foaming properties were reduced in Lc-alfalfa progeny compared with parental non-transgenic alfalfa but not compared with AC Grazeland. However, differences between the Lc-alfalfa progeny and other cultivars were small. Therefore, further increases in mono/polymeric anthocyanidin accumulation in alfalfa are required in order to develop an alfalfa cultivar with superior nutritional and bloat preventing characteristics compared to currently available alfalfa cultivars.

Grazing cattle on alfalfa (Medicago sativa L.) would be economically beneficial, but its rapid initial rate of protein degradation results in pasture bloat, low efficiency of protein utilization and excessive N pollution into the environment. Introducing a gene that stimulates the accumulation of mono/polymeric anthocyanidins might reduce the ruminal protein degradation rate and reduce bloat related foam stability. The overall objective of this thesis was to evaluate newly developed anthocyanidin-accumulating Lc-alfalfa progeny for nutritional properties (composition, site of degradation and molecular structure), environmental emissions and bloat characteristics. The objective of the first study was to determine survival and phytochemical and chemical profiles of Lc-alfalfa progeny (BeavLc1, RambLc3 and RangLc4) and their non-transgenic (NT) parental cultivars (Beaver, Rambler and Rangelander). Lc-alfalfa forage accumulated enhanced amounts of anthocyanidin, with an average concentration of 197.4 µg/g DM, while proanthocyanidin (i.e. condensed tannins) were not detected. Both of these metabolites were absent in the NT-parental varieties. Lc-alfalfa progeny had ~3 % less crude protein (CP) and ~3 % more carbohydrates (CHO), which resulted in their 11 g/kg lower N:CHO ratio compared with NT-alfalfa. Total rumen-degradable N:CHO ratio based on chemical analysis was 12.9 g/kg lower in Lc-alfalfa compared with NT-alfalfa. The objective of the second study was to evaluate in vitro degradation, fermentation and microbial-N partitioning of three forage color phenotypes [green, light purple-green (LPG) and purple-green (PG)] within Lc-progeny and their parental green NT-alfalfa varieties. Purple-green-Lc alfalfa accumulated more anthocyanidin than Green-Lc with LPG-Lc intermediate. Gas, methane and ammonia accumulation rates were slower for the two purple-Lc phenotypes compared with NT-alfalfa with Green-Lc intermediate. Effective degradable DM and N were lower in the three Lc-phenotypes compared with NT-alfalfa. Anthocyanidin concentration correlated negatively with gas and methane production rates and effective degradability of DM and N. The objectives of the third study were to evaluate in situ ruminal degradation characteristics and synchronization ratios, and to model protein availability to dairy cattle and net energy for lactation of three Lc-alfalfa progenies, BeavLc1, RambLc3 and RangLc4 and the cultivar AC Grazeland (selected for a low initial rate of ruminal degradation). Anthocyanidin accumulation was on average 163.4 ìg/g DM in the three Lc-progeny while AC Grazeland did not accumulate anthocyanidin. The basic chemical composition of the original samples, soluble and potentially degradable fractions and degradation characteristics of crude protein and carbohydrates were similar in Lc-alfalfa and AC Grazeland. The undegradable in situ crude protein and neutral detergent fiber fraction were, respectively, 1.3 %CP and 4.8 %CHO lower in the three Lc-progeny compared with AC Grazeland. Lc-alfalfa had a 0.34 MJ/kg DM higher net energy for lactation and tended to have a 11.9, 6.9 and 8.4 g/kg DM higher rumen degradable protein, rumen degraded protein balance and intestinal available protein, respectively, compared with AC Grazeland,. The hourly rumen degraded protein balance included an initial and substantial peak (over-supply) of protein relative to energy which was highest in RangLc4 and lowest in RambLc3. The hourly rumen degraded protein balance between 4 and 24 h was similar and more balanced for all four alfalfa populations. The objective of the fourth study was to determine foam formation and stability in vitro from aqueous leaf extracts of three Lc-alfalfa progeny (BeavLc1, RambLc3, RangLc4), parental NT-alfalfa and AC Grazeland (bloat reduced cultivar) harvested in the field at 07:00 or 18:00 h. Anthocyanidin accumulation averaged 247.5 ìg/g DM in the leaves of the three Lc-progeny. There was an interaction between population and harvest time for the foam parameters. Initial foam volume (0 min) and final foam volume (150 min) at 07:00 h were lower for AC Grazeland compared with all other treatments and lower for RangLc4 compared with the other two Lc-progeny at 0 min and NT-alfalfa at 150 min; while from the 18:00 h harvest, initial foam volume was larger for NT-alfalfa and final foam volume was larger for RambLc3 compared with AC Grazeland, BeavLc1 and RangLc4. Foam formation correlated positively (R = 0.30 to 0.44) with leaf DM content, leaf extract protein and ethanol-film content, spectroscopic vibration intensity due to all carbohydrates (CHOVI) and amide I:amide II ratio and negatively (R = -0.33 and -0.34; P<0.05) with á-helix:â-sheet ratio and amide I:CHOVI. Final foam volume correlated negatively (R = -0.53 to -0.25; P<0.05) with leaf extract pH, spectroscopic vibration intensity due to all protein structures, structural carbohydrates (SCVI) and lipids (CH2 and CH3 asymmetric stretching) and amide I:CHOVI ratio and corelated positively (R = 0.39 to 0.44; P<0.05) with CHOVI, amideI:SCVI ratio and CHOVI:SCVI ratio. In conclusion, all Lc-alfalfa progeny and phenotypes accumulated anthocyanidin in their forage. Lc-alfalfa progeny had lower protein and higher carbohydrate content which improved the nitrogen to carbohydrate balance compared to their parental NT-alfalfa cultivars. Rate of fermentation and effective degradability in vitro reduced for both purple anthocyanidin-accumulating Lc-alfalfa phenotypes compared with NT-alfalfa. Intestinal protein availability tended to be higher and net energy for lactation was higher from Lc-alfalfa progeny for dairy cattle compared with AC Grazeland. Foaming properties were reduced in Lc-alfalfa progeny compared with parental non-transgenic alfalfa but not compared with AC Grazeland. However, differences between the Lc-alfalfa progeny and other cultivars were small. Therefore, further increases in mono/polymeric anthocyanidin accumulation in alfalfa are required in order to develop an alfalfa cultivar with superior nutritional and bloat preventing characteristics compared to currently available alfalfa cultivars.

No description available.

<p>I detta arbete undersöks hur bestraffningsmetoder för att bestraffa storleken på GP-program påverkar generaliseringsförmågan. Arbetet grundar sig på ett arbete som Cavaretta och Chellapilla gjort, där de undersöker skillnaden i generaliseringsförmåga mellan bestraffningsmetoden ”Complexity Penalty functions” och ingen bestraffningsmetod.</p><p>I detta arbete har nya experiment gjorts med ”Complexity Penalty functions” och ”Adaptive parsimony pressure”, som är en annan bestraffningsmetod. Dessa bestraffningsmetoder har undersökts i samma domän som Cavaretta och Chellapilla och ytterligare i en domän för att ge en bättre bild av hur de generaliserar.</p><p>I arbetet visar det sig att användningen av någon av bestraffningsmetoderna ”Complexity Penalty functions” och ”Adaptive parsimony pressure” oftast ger bättre generaliseringsförmåga hos GP-program. Detta motsäger det Cavaretta och Chellapilla kommer fram till i sitt arbete. ”Adaptive parsimony pressure” verkar också vara bättre på att generalisera än ”Complexity Penalty functions”.</p>

A series of experiments were conducted to compare nine new sainfoin populations developed to persist in mixtures with alfalfa under a multiple-cut management. In trials at Lethbridge under rain-fed and irrigated conditions, new sainfoin populations produced higher (P<0.05) dry matter yields as compared to Nova sainfoin. New cultivars persisted for three production years in mixed stands with alfalfa accounting for >20% DM at each harvest. Condensed tannin concentrations in sainfoin were highest at the bud stage. One new sainfoin population, LRC-3519 seeded in alternate rows with alfalfa caused a reduction (p<0.001) in bloat incidence by 98% as compared to Nova-alfalfa stands. Average daily gains (>1.0 kg d-1) of steers on alfalfa-sainfoin mixed pastures were similar (p>0.05). Seeding of these new sainfoin populations in mixed stands with alfalfa could prove to be a means of taking advantage of the productivity of mixed forage legume pastures while preventing bloat in grazing ruminants.

I detta arbete undersöks hur bestraffningsmetoder för att bestraffa storleken på GP-program påverkar generaliseringsförmågan. Arbetet grundar sig på ett arbete som Cavaretta och Chellapilla gjort, där de undersöker skillnaden i generaliseringsförmåga mellan bestraffningsmetoden ”Complexity Penalty functions” och ingen bestraffningsmetod. I detta arbete har nya experiment gjorts med ”Complexity Penalty functions” och ”Adaptive parsimony pressure”, som är en annan bestraffningsmetod. Dessa bestraffningsmetoder har undersökts i samma domän som Cavaretta och Chellapilla och ytterligare i en domän för att ge en bättre bild av hur de generaliserar. I arbetet visar det sig att användningen av någon av bestraffningsmetoderna ”Complexity Penalty functions” och ”Adaptive parsimony pressure” oftast ger bättre generaliseringsförmåga hos GP-program. Detta motsäger det Cavaretta och Chellapilla kommer fram till i sitt arbete. ”Adaptive parsimony pressure” verkar också vara bättre på att generalisera än ”Complexity Penalty functions”.