RESUMO

Pregnancy rate is a major determinant of population dynamics of wild ungulates and of productivity of livestock systems. Allocation of feeding resources, including stocking rates, prior to and during the breeding season is a crucial determinant of this vital rate. Thus, quantification of effects and interaction among multiple factors that affect pregnancy rate is essential for management and conservation of pasture-based systems. Pregnancy rate of 2982 heifers and primiparous cows was studied as a function of animal category, average daily gain during the breeding season, stocking rate, pasture type and body weight at the beginning of the breeding season. Data were obtained from 43 experiments conducted in commercial ranches and research stations in the Pampas region between 1976 and 2015. Stocking rate ranged from 200 to 464 kg live weight ha-1, which brackets values for most of the grazinglands in similar regions. Age at breeding was 14-36 months (24.6±7.5 months); initial breeding weights were 129-506 kg and 194-570 kg for heifers and primiparous cows. Pregnancy rate was modeled with an apriori set of explanatory variables where proximate variables (breed, body weight at start of breeding, weight gain during breeding and category) were included first and subsequently modeled as functions of other variables (pasture type, supplementation and stocking rate). This modeling approach allowed detection of direct and indirect effects (through nutrition and body weight) of factors that affect pregnancy rate. Bos taurus breeds (N = 1058) had higher pregnancy rate than B. Taurus x B. indicus crossbreed (N = 1924) females. Pregnancy rate of heifers and primiparous cows grazing in natural grasslands decreased with increasing stocking rate, but no effect of stocking rate was detected in cultivated and improved pastures. Pregnancy rate increased with increasing average daily gain during the breeding season. Use of cultivated or improved natural pastures promotes higher pregnancy rate, as well as allows an increase in stocking rate at the regional level. Body weight at the start of the breeding season is the primary determinant of pregnancy rates in heifer and primiparous cows.

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The aim of this study was to evaluate the effects of conception weight and gestational weight gain on performance and productive efficiency in beef cows and their calves. Eighty-eight primiparous, three-year old Braford females were used, divided according to weight at conception and gestational performance (High and Low): cows with a low conception weight and low gestational weight gain (LL), cows with low conception weight and high gestational weight gain (LH), cows with high conception weight and low gestational weight gain (HL), and cows with high conception weight and high gestational weight gain (HH). At calving, HH cows were heavier than LH and HL and these were heavier than LL cows. Male calves born to HH cows were superior in body weight to those born to LL cows at 150, 210 and 365 days. Female calves born to HH, HL or LH cows were superior to those born to LL cows in pregnancy at 14 months of age. The LL and HL cows were more efficient in calf production. Actual fertility was influenced by the nutritional level of the herd, where HH cows were superior than LL cows. Better cow herd nutrition increases the development and performance of the progeny.

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RESUMO

The calving period influences productivity and reproductive efficiency the herds. The objective of this study was to evaluate two calving months (October and November) and their effect on the efficiency of a breeding herd for three consecutive years. A total of 298 Braford cows were evaluated at three, four, and five years of age, with their calves early-weaned at 148 days of age. The performance characteristics of the cow/calf pairs were evaluated with the calving month and calf sex as the independent variables. The animals were kept as a single group for the three years of observation. Cows calving in November were heavier and had a higher body condition score at calving. Cows calving in October were heavier and produced heavier calves at weaning. Male calves were heavier at birth and weaning than females (30.8 vs 28.6 kg and 118.9 vs 114.7 kg, respectively). The pregnancy rate was 82.35 and 69.23% for cows calving in October and November, respectively. Calving intervals were shorter in cows calving in November. Cows calving in October were more efficient compared with those calving in November, with a higher actual fertility rate. The production of kilograms of the calf/cow pair was higher for cows calving in October.(AU)

O período do parto influencia a produtividade e a eficiência reprodutiva dos rebanhos. O objetivo deste estudo foi avaliar dois meses de parto (outubro e novembro) e seus efeitos sobre a eficiência de um rebanho de cria por três anos consecutivos. Foram realizadas 298 avaliações de vacas Braford aos três, quatro e cinco anos de idade, com seus bezerros desmamados aos 148 dias de idade. As características de desempenho dos pares vaca / bezerro foram avaliadas com o mês e o sexo do bezerro como variáveis independentes. Os animais foram mantidos em um único grupo nos três anos de observação. As vacas que pariram em novembro foram mais pesadas e tiveram maior escore de condição corporal no parto. As vacas que pariram em outubro foram mais pesadas e produziram bezerros mais pesados no desmame. Os bezerros machos foram mais pesados ao nascer e ao desmame do que as fêmeas (30,8 vs 28,6 kg e 118,9 vs 114,7 kg, respectivamente). A taxa de prenhez foi de 82,35 e 69,23% para as vacas que pariram em outubro e novembro, respectivamente. Os intervalos de partos foram mais curtos nas vacas paridas em novembro. As vacas que pariram em outubro foram mais eficientes quando comparadas com as que pariram em novembro, com maior taxa de fertilidade real. A produção de quilogramas do par bezerro / vaca foi maior em vacas que pariram em outubro.(AU)

Assuntos

RESUMO

The calving period influences productivity and reproductive efficiency the herds. The objective of this study was to evaluate two calving months (October and November) and their effect on the efficiency of a breeding herd for three consecutive years. A total of 298 Braford cows were evaluated at three, four, and five years of age, with their calves early-weaned at 148 days of age. The performance characteristics of the cow/calf pairs were evaluated with the calving month and calf sex as the independent variables. The animals were kept as a single group for the three years of observation. Cows calving in November were heavier and had a higher body condition score at calving. Cows calving in October were heavier and produced heavier calves at weaning. Male calves were heavier at birth and weaning than females (30.8 vs 28.6 kg and 118.9 vs 114.7 kg, respectively). The pregnancy rate was 82.35 and 69.23% for cows calving in October and November, respectively. Calving intervals were shorter in cows calving in November. Cows calving in October were more efficient compared with those calving in November, with a higher actual fertility rate. The production of kilograms of the calf/cow pair was higher for cows calving in October.

O período do parto influencia a produtividade e a eficiência reprodutiva dos rebanhos. O objetivo deste estudo foi avaliar dois meses de parto (outubro e novembro) e seus efeitos sobre a eficiência de um rebanho de cria por três anos consecutivos. Foram realizadas 298 avaliações de vacas Braford aos três, quatro e cinco anos de idade, com seus bezerros desmamados aos 148 dias de idade. As características de desempenho dos pares vaca / bezerro foram avaliadas com o mês e o sexo do bezerro como variáveis independentes. Os animais foram mantidos em um único grupo nos três anos de observação. As vacas que pariram em novembro foram mais pesadas e tiveram maior escore de condição corporal no parto. As vacas que pariram em outubro foram mais pesadas e produziram bezerros mais pesados no desmame. Os bezerros machos foram mais pesados ao nascer e ao desmame do que as fêmeas (30,8 vs 28,6 kg e 118,9 vs 114,7 kg, respectivamente). A taxa de prenhez foi de 82,35 e 69,23% para as vacas que pariram em outubro e novembro, respectivamente. Os intervalos de partos foram mais curtos nas vacas paridas em novembro. As vacas que pariram em outubro foram mais eficientes quando comparadas com as que pariram em novembro, com maior taxa de fertilidade real. A produção de quilogramas do par bezerro / vaca foi maior em vacas que pariram em outubro.

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RESUMO

This study aimed to assess the effects of carp pituitary extract (CPE), follicle stimulating hormone (FSH) and luteinizing hormone (LH) on zebrafish oocyte maturation and the ability of these mature oocytes to be fertilized and developed until hatching. Stage III follicles were matured in eight treatments: five concentrations of CPE (16, 32, 48, 64 and 80 µg/mL), one of FSH (0.5 µg/mL), one of LH (0.5 µg/mL), or one combination of FSH (0.5 µg/mL) and LH (0.5 µg/mL). Maturation rates in CPE treatments were 12.8% (16 µg/mL), 24.8% (32 µg/mL), 27.0% (48 µg/mL), 22.7% (64 µg/mL) and 9.6% (80 µg/mL); in FSH was 15.7% (0.5 µg/mL), in LH was 31.8% (0.5 µg/mL) and in FSH (0.5 µg/mL) combined with LH (0.5 µg/mL) it was 50.4%. In vitro fertilization was performed in all treatments; however, only the treatment combining FSH and LH resulted in fertilized oocytes. After maturation using FSH combined with LH, the cleavage rate was 33.3% and hatching rate of live larvae was 20.0%. These results showed that FSH combined with LH was effective in IVM of zebrafish oocyte.

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RESUMO

Body development and reproductive performance of a hundred forty-two 14 to 15-month-old heifers, classified at weaning according to frame size as small, medium, and large, were evaluated. The parameters evaluated were: body weight, hip height, body condition score, weight gain, ovarian activity, and pregnancy rate. At weaning, body weight and hip height were significantly different among frame scores, (small ­ 133.0 kg, 92.2 cm; medium ­ 158.5 kg, 96.6 cm; and large ­ 185.2 kg; 100.2 cm). After weaning, heifers grazed together on natural pastures during the autumn and on ryegrass (Lolium multiflorum La.) during the winter and spring. Frame score differences remained until the beginning of the breeding season (BS), starting on average at 14 months of age. Weight gain between weaning and the beginning of BS was not different among frame scores (0.740 kg/day, on average). Body weights at the beginning of the BS were significantly different, of 255.7 kg (53.3% of the mature weight) for small heifers, 285.0 kg (59.4%) for medium heifers, and 307.6 kg (64.1%) for large heifers. Ovarian activity at the beginning of the BS was not different among the three groups. The average weight gain values during the BS of 0.492, 0.472, and 0.421 kg/day for small, medium, and large heifers, respectively, were significantly different. Pregnancy rates were not different among groups (small, 71.4%; medium, 76.4%; and large, 76.5%). Frame score did not influence the reproductive performance of heifers, but the small and medium heifers conceived 29 and 20 days earlier, respectively, than the large heifers.(AU)

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RESUMO

To strategically define the best stocking rate management strategy for ryegrass, it is important to know the growth process of forage plants in detail. The study was conducted to analyze the leaf biomass flows and the defoliation intensity and frequency of Italian ryegrass (Lolium multiflorum Lam) grazed by heifers fed exclusively on pasture or on pasture and supplemented with corn or white oat grain. The experimental design was completely randomized following a repeated measures arrangement with three feeding systems and three area replications. Biomass flows (kg DM leaf blades ha1 day1) for leaf growth (40.6), leaf senescence (40.7), and leaf intake (29.7) were similar in the different feeding systems. Leaf blade intake adjusted to body weight was lower in supplemented heifers regardless of grain type. Actual and potential utilization efficiencies and ryegrass biomass net balance were not affected by feeding system. The leaf intake flow was 1.4 times lower than the growth flow, resulting in an actual utilization efficiency less than one (0.7), whereas the senescence flow was higher than the growth flow, resulting in a negative potential utilization efficiency (0.2). Leaf defoliation intensity was similar (54.4%) across feeding systems and defoliation frequency was higher in supplemented heifers. The 29.2% increase in stocking rate of heifers fed corn or oat grain as supplement did not affect the dynamics of ryegrass biomass flows, but reduced leaf blade intake adjusted to heifer body weight leading to alterations in the defoliation frequency of ryegrass pasture.(AU)

Para definir estrategicamente a melhor taxa de lotação para o azevém é importante conhecer em detalhe o processo de crescimento dessa forrageira. O estudo foi realizado para avaliar os fluxos de biomassa foliar, a intensidade e a frequência de desfolhação de azevém (Lolium multiflorum Lam), pastejado por bezerras exclusivamente em pastejo, ou em pastejo e recebendo grão de milho ou de aveia como suplemento. O delineamento experimental foi inteiramente casualizado com medidas repetidas no tempo, três sistemas alimentares e três repetições de área. Os fluxos (kg de MS de lâminas foliares ha-1 dia-1) de crescimento (40,6), senescência (40,7) e consumo (29,7) foram similares nos diferentes sistemas alimentares. O consumo de lâminas foliares em relação ao peso corporal foi menor quando as bezerras receberam suplemento, independente do tipo de grão. Os sistemas alimentares testados não influenciaram nas eficiências real e potencial de utilização bem como no balanço liquido de utilização do azevém. O fluxo de consumo das laminas foliares 1,4 vezes mais baixo que o fluxo de crescimento ocasionou em eficiência real de utilização inferior a um (0,7) e o fluxo de senescência mais alto que o fluxo de crescimento das lâminas foliares gerou uma eficiência potencial de utilização negativa (-0,2). As lâminas foliares foram desfolhadas com intensidade similar (54,4%) nos diferentes sistemas alimentares. A frequência de desfolhação do azevém aumentou quando as bezerras foramsuplementadas. O aumento de 29,2% na taxa de lotação ocasionado pelo uso do grão de milho ou do grão de aveia como suplemento não alterou a dinâmica dos fluxos de biomassa do azevém, porém reduziu o consumo de lâminas foliares em relação ao peso corporal das bezerras e ocasionou alterações na frequência de desfolhação do azevém.(AU)

Assuntos

RESUMO

To strategically define the best stocking rate management strategy for ryegrass, it is important to know the growth process of forage plants in detail. The study was conducted to analyze the leaf biomass flows and the defoliation intensity and frequency of Italian ryegrass (Lolium multiflorum Lam) grazed by heifers fed exclusively on pasture or on pasture and supplemented with corn or white oat grain. The experimental design was completely randomized following a repeated measures arrangement with three feeding systems and three area replications. Biomass flows (kg DM leaf blades ha1 day1) for leaf growth (40.6), leaf senescence (40.7), and leaf intake (29.7) were similar in the different feeding systems. Leaf blade intake adjusted to body weight was lower in supplemented heifers regardless of grain type. Actual and potential utilization efficiencies and ryegrass biomass net balance were not affected by feeding system. The leaf intake flow was 1.4 times lower than the growth flow, resulting in an actual utilization efficiency less than one (0.7), whereas the senescence flow was higher than the growth flow, resulting in a negative potential utilization efficiency (0.2). Leaf defoliation intensity was similar (54.4%) across feeding systems and defoliation frequency was higher in supplemented heifers. The 29.2% increase in stocking rate of heifers fed corn or oat grain as supplement did not affect the dynamics of ryegrass biomass flows, but reduced leaf blade intake adjusted to heifer body weight leading to alterations in the defoliation frequency of ryegrass pasture.

Para definir estrategicamente a melhor taxa de lotação para o azevém é importante conhecer em detalhe o processo de crescimento dessa forrageira. O estudo foi realizado para avaliar os fluxos de biomassa foliar, a intensidade e a frequência de desfolhação de azevém (Lolium multiflorum Lam), pastejado por bezerras exclusivamente em pastejo, ou em pastejo e recebendo grão de milho ou de aveia como suplemento. O delineamento experimental foi inteiramente casualizado com medidas repetidas no tempo, três sistemas alimentares e três repetições de área. Os fluxos (kg de MS de lâminas foliares ha-1 dia-1) de crescimento (40,6), senescência (40,7) e consumo (29,7) foram similares nos diferentes sistemas alimentares. O consumo de lâminas foliares em relação ao peso corporal foi menor quando as bezerras receberam suplemento, independente do tipo de grão. Os sistemas alimentares testados não influenciaram nas eficiências real e potencial de utilização bem como no balanço liquido de utilização do azevém. O fluxo de consumo das laminas foliares 1,4 vezes mais baixo que o fluxo de crescimento ocasionou em eficiência real de utilização inferior a um (0,7) e o fluxo de senescência mais alto que o fluxo de crescimento das lâminas foliares gerou uma eficiência potencial de utilização negativa (-0,2). As lâminas foliares foram desfolhadas com intensidade similar (54,4%) nos diferentes sistemas alimentares. A frequência de desfolhação do azevém aumentou quando as bezerras foramsuplementadas. O aumento de 29,2% na taxa de lotação ocasionado pelo uso do grão de milho ou do grão de aveia como suplemento não alterou a dinâmica dos fluxos de biomassa do azevém, porém reduziu o consumo de lâminas foliares em relação ao peso corporal das bezerras e ocasionou alterações na frequência de desfolhação do azevém.

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RESUMO

The migratory species piabanha does not reproduce in lentic environments since it requires environmental stimuli for the maturation and extrusion of gametes, and therefore hormonal induction is mandatory. Current study compares the seminal characteristics of Brycon insignis without any hormonal induction (Control - Ctrl) and with two types of hormonal inductors, or rather, carp pituitary extract (T1 - 2.5 mg kg-1 body weight) and GnRH analogues, the latter applied in two different concentrations (T2 - 0.7 mg kg-1 body weight and T3 - 1.4 mg kg-1 body weight). Post-induction analyses showed that the hormones increased the motility rate - Ctrl (95%), T1 (100%), T2 (100%) and T3 (98%), although sperm concentration - Ctrl (11.52 x 109); T1 (4.37 x 109); T2 (4.34 x 109); T3 (4.01 x 109) decreased. Assessments for sperm vigor, motility time and spermatic morphology did not vary with hormonal induction. Hormonal inducer does not alter negatively the seminal characteristics of the piabanha, and the choice for the proper hormone depends on the preference of the dispenser.

A espécie migradora piabanha não possui a capacidade de reproduzir em ambientes lênticos devido à necessidade de estímulos ambientais para a maturação e extrusão dos gametas, por isso a necessidade da indução hormonal. No presente estudo, as características seminais do Brycon insignis foram comparadas sem indução hormonal (Ctrl) e utilizando dois tipos de indutores hormonais - Extrato de Hipófise de Carpa (T1 - 2,5 mg kg-1 de peso vivo) e Análogos de GnRH, sendo este último aplicado em duas concentrações distintas (T2 - 0,7 mg kg -1 de peso vivo e T3 - 1,4 mg kg-1 de peso vivo). As análises realizadas após a indução mostraram que os hormônios utilizados produziram um aumento da taxa de motilidade - Ctrl (95%), T1 (100%), T2 (100%) e T3 (98%), porém houve uma diminuição na concentração espermática - Ctrl (11,52 x 109), T1 (4,37 x 109), T2 (4,34 x 109) e T3 (4,01 x 109). Os restantes das avaliações, vigor espermático, tempo de motilidade e morfologia espermática não apresentaram variações com a indução hormonal. Portanto, a utilização do indutor hormonal não altera negativamente as características seminais de piabanha, e a escolha do mesmo se deve à preferência do manipulador.

Assuntos

RESUMO

The migratory species piabanha does not reproduce in lentic environments since it requires environmental stimuli for the maturation and extrusion of gametes, and therefore hormonal induction is mandatory. Current study compares the seminal characteristics of Brycon insignis without any hormonal induction (Control - Ctrl) and with two types of hormonal inductors, or rather, carp pituitary extract (T1 - 2.5 mg kg-1 body weight) and GnRH analogues, the latter applied in two different concentrations (T2 - 0.7 mg kg-1 body weight and T3 - 1.4 mg kg-1 body weight). Post-induction analyses showed that the hormones increased the motility rate - Ctrl (95%), T1 (100%), T2 (100%) and T3 (98%), although sperm concentration - Ctrl (11.52 x 109); T1 (4.37 x 109); T2 (4.34 x 109); T3 (4.01 x 109) decreased. Assessments for sperm vigor, motility time and spermatic morphology did not vary with hormonal induction. Hormonal inducer does not alter negatively the seminal characteristics of the piabanha, and the choice for the proper hormone depends on the preference of the dispenser. (AU)

A espécie migradora piabanha não possui a capacidade de reproduzir em ambientes lênticos devido à necessidade de estímulos ambientais para a maturação e extrusão dos gametas, por isso a necessidade da indução hormonal. No presente estudo, as características seminais do Brycon insignis foram comparadas sem indução hormonal (Ctrl) e utilizando dois tipos de indutores hormonais - Extrato de Hipófise de Carpa (T1 - 2,5 mg kg-1 de peso vivo) e Análogos de GnRH, sendo este último aplicado em duas concentrações distintas (T2 - 0,7 mg kg-1 de peso vivo e T3 - 1,4 mg kg-1 de peso vivo). As análises realizadas após a indução mostraram que os hormônios utilizados produziram um aumento da taxa de motilidade - Ctrl (95%), T1 (100%), T2 (100%) e T3 (98%), porém houve uma diminuição na concentração espermática - Ctrl (11,52 x 109 ), T1 (4,37 x 109 ), T2 (4,34 x 109 ) e T3 (4,01 x 109 ). Os restantes das avaliações, vigor espermático, tempo de motilidade e morfologia espermática não apresentaram variações com a indução hormonal. Portanto, a utilização do indutor hormonal não altera negativamente as características seminais de piabanha, e a escolha do mesmo se deve à preferência do manipulador.(AU)

Assuntos

RESUMO

O consumo de forragem foi avaliado em novilhas de corte exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou recebendo farelo de arroz integral (FAI) com ou sem adição de ionóforo. Foi usado o óxido de cromo como indicador da produção fecal. O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, com três tratamentos e três repetições de área. Os animais foram considerados as unidades experimentais nas avaliações de consumo. O consumo de pasto pelas novilhas foi similar nos diferentes sistemas alimentares, ocasionando taxa de lotação semelhante. O fornecimento de farelo de arroz integral, com ou sem monensina, aumenta o consumo de matéria seca total. A adição de ionóforo ao FAI aumenta o desempenho individual das novilhas, sendo o seu uso recomendado quando existe o objetivo de reduzir a sua idade ao primeiro acasalamento.

The forage intake was evaluated in beef heifers exclusively in Italian ryegrass (Lolium multiflorum Lam.) pasture or receiving rice bran with or without addition of ionophore. Chromic oxide was used as a fecal production indicator. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The animals were considered experimental units for intake evaluations. The pasture intake by heifers was similar at different feeding systems causing similar stocking rate. The supply of rice bran with or without monensin increased the total dry matter intake. The individual heifers performance was increased with ionophore addition to rice bran. Ionophore is recommended when there is a goal to reduce the age of beef heifers at their first mating.

RESUMO

O consumo de forragem foi avaliado em novilhas de corte exclusivamente em pastagem de azevém (Lolium multiflorum Lam.) ou recebendo farelo de arroz integral (FAI) com ou sem adição de ionóforo. Foi usado o óxido de cromo como indicador da produção fecal. O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, com três tratamentos e três repetições de área. Os animais foram considerados as unidades experimentais nas avaliações de consumo. O consumo de pasto pelas novilhas foi similar nos diferentes sistemas alimentares, ocasionando taxa de lotação semelhante. O fornecimento de farelo de arroz integral, com ou sem monensina, aumenta o consumo de matéria seca total. A adição de ionóforo ao FAI aumenta o desempenho individual das novilhas, sendo o seu uso recomendado quando existe o objetivo de reduzir a sua idade ao primeiro acasalamento.(AU)

The forage intake was evaluated in beef heifers exclusively in Italian ryegrass (Lolium multiflorum Lam.) pasture or receiving rice bran with or without addition of ionophore. Chromic oxide was used as a fecal production indicator. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The animals were considered experimental units for intake evaluations. The pasture intake by heifers was similar at different feeding systems causing similar stocking rate. The supply of rice bran with or without monensin increased the total dry matter intake. The individual heifers performance was increased with ionophore addition to rice bran. Ionophore is recommended when there is a goal to reduce the age of beef heifers at their first mating.(AU)

Assuntos

RESUMO

The experiment aimed at evaluating leaf biomass flow, intensity and frequency of defoliation of Alexandergrass (Urochloa plantaginea (Link) Hitch) by beef heifers exclusively on pasture or that grazed and received protein salt. A completely randomized experimental design was used with repeated measures over time, two treatments and two area replications, with three Angus test heifers by paddock. Leaf blade intake flow is 18% superior for heifers exclusively on pasture. Grazing intensity (59.8%) is similar when heifers receive protein salt or not. Heifers receiving protein salt reduce by one day the defoliation frequency of tillers. The supply of protein salt for beef heifers grazing Alexandergrass affects the herbivore-plant relationship, decreasing intake flow and leaf blade defoliation frequency.

O experimento foi conduzido para avaliar os fluxos de biomassa foliar, intensidade e frequência de desfolhação em papuã (Urochloa plantaginea (Link) Hitch), pastejado por bezerras de corte exclusivamente em pastejo ou em pastejo e recebendo sal proteinado. O delineamento foiinteiramente casualizado, com medidas repetidas no tempo, dois tratamentos e duas repetições de área, com três bezerras testes da raça Angus por piquete. O fluxo de consumo de lâminas foliares é18% superior quando as bezerras permanecem exclusivamente em pastejo. A intensidade de pastejo(59,8%) é semelhante quando as bezerras recebem sal proteinado ou não. Bezerras que recebem suplemento reduzem em um dia a frequência de desfolhação dos perfilhos. O fornecimento de salproteinado para bezerras de corte em pastejo em papuã resulta em alterações na relação herbívoro planta reduzindo o fluxo de consumo e a frequência de desfolhação de lâminas foliares.

Assuntos

RESUMO

The experiment aimed at evaluating leaf biomass flow, intensity and frequency of defoliation of Alexandergrass (Urochloa plantaginea (Link) Hitch) by beef heifers exclusively on pasture or that grazed and received protein salt. A completely randomized experimental design was used with repeated measures over time, two treatments and two area replications, with three Angus test heifers by paddock. Leaf blade intake flow is 18% superior for heifers exclusively on pasture. Grazing intensity (59.8%) is similar when heifers receive protein salt or not. Heifers receiving protein salt reduce by one day the defoliation frequency of tillers. The supply of protein salt for beef heifers grazing Alexandergrass affects the herbivore-plant relationship, decreasing intake flow and leaf blade defoliation frequency.(AU)

O experimento foi conduzido para avaliar os fluxos de biomassa foliar, intensidade e frequência de desfolhação em papuã (Urochloa plantaginea (Link) Hitch), pastejado por bezerras de corte exclusivamente em pastejo ou em pastejo e recebendo sal proteinado. O delineamento foiinteiramente casualizado, com medidas repetidas no tempo, dois tratamentos e duas repetições de área, com três bezerras testes da raça Angus por piquete. O fluxo de consumo de lâminas foliares é18% superior quando as bezerras permanecem exclusivamente em pastejo. A intensidade de pastejo(59,8%) é semelhante quando as bezerras recebem sal proteinado ou não. Bezerras que recebem suplemento reduzem em um dia a frequência de desfolhação dos perfilhos. O fornecimento de salproteinado para bezerras de corte em pastejo em papuã resulta em alterações na relação herbívoro planta reduzindo o fluxo de consumo e a frequência de desfolhação de lâminas foliares.(AU)

Assuntos

RESUMO

The experiment aimed at evaluating leaf biomass flow, intensity and frequency of defoliation of Alexandergrass (Urochloa plantaginea (Link) Hitch) by beef heifers exclusively on pasture or that grazed and received protein salt. A completely randomized experimental design was used with repeated measures over time, two treatments and two area replications, with three Angus test heifers by paddock. Leaf blade intake flow is 18% superior for heifers exclusively on pasture. Grazing intensity (59.8%) is similar when heifers receive protein salt or not. Heifers receiving protein salt reduce by one day the defoliation frequency of tillers. The supply of protein salt for beef heifers grazing Alexandergrass affects the herbivore-plant relationship, decreasing intake flow and leaf blade defoliation frequency.

RESUMO

The effects of several supplementation frequencies on forage use (leaf tissue flow, intensity and frequency of defoliation) in Alexandergrass (Urochloa plantaginea (Link) Hitch) were evaluated. The heifers remained exclusively on pasture or received whole oat grain seven days/week or five days/week (Monday to Friday). The weekly amount of supplement was similar for both frequencies. The experimental design was completely randomized following a repeated measure arrangement, with three treatments and two area replications. Leaf tissue flow, frequency and intensity of defoliation are similar when heifers remain exclusively on Alexandergrass pasture or receive oat grain on different frequencies.(AU)

Foi avaliado o efeito de diferentes frequências de suplementação sobre o uso da pastagem (fluxo de tecido foliar, intensidade e frequência de desfolhação) em papuã (Urochloa plantaginea (Link) Hitch). As bezerras de corte permaneceram exclusivamente em pastejo ou receberam grão inteiro de aveia durante sete ou cinco dias por semana (de segunda à sexta feira). A quantidade semanal de suplemento foi similar nas duas frequências. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, três tratamentos e duas repetições de área. Os fluxos de tecidos, a frequência e intensidade de desfolhação são similares quando as bezerras permanecem exclusivamente em pastejo ou recebem grão de aveia em diferentes frequências.(AU)

Assuntos

RESUMO

The effects of several supplementation frequencies on forage use (leaf tissue flow, intensity and frequency of defoliation) in Alexandergrass (Urochloa plantaginea (Link) Hitch) were evaluated. The heifers remained exclusively on pasture or received whole oat grain seven days/week or five days/week (Monday to Friday). The weekly amount of supplement was similar for both frequencies. The experimental design was completely randomized following a repeated measure arrangement, with three treatments and two area replications. Leaf tissue flow, frequency and intensity of defoliation are similar when heifers remain exclusively on Alexandergrass pasture or receive oat grain on different frequencies.

Foi avaliado o efeito de diferentes frequências de suplementação sobre o uso da pastagem (fluxo de tecido foliar, intensidade e frequência de desfolhação) em papuã (Urochloa plantaginea (Link) Hitch). As bezerras de corte permaneceram exclusivamente em pastejo ou receberam grão inteiro de aveia durante sete ou cinco dias por semana (de segunda à sexta feira). A quantidade semanal de suplemento foi similar nas duas frequências. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, três tratamentos e duas repetições de área. Os fluxos de tecidos, a frequência e intensidade de desfolhação são similares quando as bezerras permanecem exclusivamente em pastejo ou recebem grão de aveia em diferentes frequências.

RESUMO

The effects of several supplementation frequencies on forage use (leaf tissue flow, intensity and frequency of defoliation) in Alexandergrass (Urochloa plantaginea (Link) Hitch) were evaluated. The heifers remained exclusively on pasture or received whole oat grain seven days/week or five days/week (Monday to Friday). The weekly amount of supplement was similar for both frequencies. The experimental design was completely randomized following a repeated measure arrangement, with three treatments and two area replications. Leaf tissue flow, frequency and intensity of defoliation are similar when heifers remain exclusively on Alexandergrass pasture or receive oat grain on different frequencies.

Foi avaliado o efeito de diferentes frequências de suplementação sobre o uso da pastagem (fluxo de tecido foliar, intensidade e frequência de desfolhação) em papuã (Urochloa plantaginea (Link) Hitch). As bezerras de corte permaneceram exclusivamente em pastejo ou receberam grão inteiro de aveia durante sete ou cinco dias por semana (de segunda à sexta feira). A quantidade semanal de suplemento foi similar nas duas frequências. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, três tratamentos e duas repetições de área. Os fluxos de tecidos, a frequência e intensidade de desfolhação são similares quando as bezerras permanecem exclusivamente em pastejo ou recebem grão de aveia em diferentes frequências.