RESUMO

This study evaluated the effects of breed on voluntary preferential intake of two sources of Cu, Mn, and Zn when added to white salt-based trace mineral supplement (days 0 to 55; experiment 1) and protein supplement (days 56 to 112; experiment 2). On day 0, Nelore and ½ Angus × ½ Nelore heifers (n = 20/breed) were stratified by breed, body weight (BW = 347 ±â€…82 kg), and age (12 to 30 mo), and randomly allocated into 1 of the 40 drylot pens (1 heifer/pen). Both experiments were divided into washout (days 0 to 27 in experiment 1 and days 56 to 83 in experiment 2) and preferential intake periods (days 28 to 55 in experiment 1 and days 84 to 112 in experiment 2). During the respective preferential intake period, heifers were provided simultaneous free-choice access to sulfate (SUL) and hydroxychloride (HYD) sources of Cu, Mn, and Zn mixed into salt-based trace mineral supplements from days 28 to 55 (experiment 1) and then protein supplements from days 84 to 112 (experiment 2). Heifers were provided free-choice access to Tifton 85 (Cynodon sp.) hay from days 0 to 112. Effects of breed × source × day of the study were detected (P ≤ 0.05) for daily trace mineral intake from days 28 to 56 and days 84 to 112. Angus × Nelore heifers consumed a greater amount of SUL vs. HYD supplements on days 31 to 33 (P = 0.02) and HYD vs. SUL supplements on days 37 to 42 (P ≤ 0.02), whereas Nelore heifers consumed more HYD vs. SUL supplements on days 31 to 33 and 43 to 51 (P ≤ 0.05). Both breeds consumed (P ≤ 0.05) a greater amount of protein supplement containing HYD vs. SUL from days 84 to 112, but the differences in protein supplement intake increased (P ≤ 0.04) in greater magnitude for Nelore vs. Angus × Nelore heifers. Supplement intake coefficient of variation (CV) from days 28 to 41 and days 84 to 97 tended (P = 0.06) to be greater for Nelore vs. Angus × Nelore heifers. Effects of breed × source were detected (P = 0.02) for supplement intake CV from days 84 to 112. Intake CV of supplements added with HYD did not differ (P ≥ 0.40) between Nelore vs. Angus × Nelore heifers but was greater (P < 0.01) for Nelore vs. Angus × Nelore heifers fed SUL supplements. Overall, Nelore heifers had greater preferential intake for mineral and protein supplements containing hydroxychloride vs. sulfate sources compared to Angus × Nelore heifers. Hydroxychloride sources encouraged voluntary intake and reduced variation in supplement consumption compared to SUL sources of the same metals.

RESUMO

This experiment was conducted to determine the effect of earlier weaning in addition to biocholine supplementation on age at puberty of Brangus heifers. Brangus calves were randomized and divided into three weaning ages groups, at 30 (Hyper-early weaning; HW), 75 (Early weaning; EW) and 180 days (Conventional weaning; CW). Then, calves were supplemented using the additive Biocholine (BIO) or not (CON). Animals were subjected to puberty induction and the presence of estrus was observed for 7 days. In addition, transrectal ultrasonography was performed to assess the ovarian activity and the presence of corpus luteum to determine heifer puberty. We also evaluated the body weight (BW; Kg), hip height (HH; cm), thoracic perimeter (TP; cm) and BW:HH ratio during the experimental period. BIO group showed higher ADG (>226 g/day) when the animals were exposed to ryegrass pasture compared to CON (P < 0.05). We observed an interaction between weaning x biocholine and CW-BIO heifers showed greater HH more compared to CW-CON (P < 0.05). Overall, animals that have reached puberty at day 8 after puberty induction showed 331.0 ± 5.04 kg BW, 122.0 ± 0.56 cm HH and 165.4 ± 0.75 cm TP and 2.7 ± 0.03 BW:HH. At the time of ovulation detection, the heifers from the HW group had 32.1 kg BW, 3.93 cm HH and 0.18 cm BW:HH greater compared to CW (P < 0.05). The BIO supplementation together with ryegrass pasture, led to an increase in ADG weight throughout the evaluated period. We concluded that HW heifers showed an adequate body development throughout the experimental period until puberty appearance at the same age as others weaned groups.

Assuntos

RESUMO

The effects of higher supplementation levels for young Nellore heifers fed tropical forages including their influence on puberty, need to be understood. This study investigated the influence of high and moderate supplementation levels on puberty onset and the productive performance of Nellore heifers. Thirty-six Nellore heifers (225 + 3.52 kg) were used in a completely randomized design, with three treatments: (I) no concentrate (control); (II) concentrate supplement at 4 g/kg body weight (BW); (III) concentrate supplement at 8 g/kg BW. Increased supplement level led to a linear increase in average daily gain (P < 0.05). The high supplementation level (8 g/kg BW) had the highest proportion of corpus luteum presence (82% of heifers), compared to the 4 g/kg BW treatment group (67%) and the control group (33%; P < 0.05). Our findings indicate that providing a high level of energy supplementation to Nellore heifers for approximately 100 d improves performance and increases the proportion of heifers that reach puberty.

Assuntos

RESUMO

ABSTRACT Replacement beef heifers in extensive systems of the neotropical savannas of Colombia are low priority animals and are assigned to native savannas and low-quality pastures, with scarcely researched long-term consequences. The study pooled data from four contemporary grazing experiments to determine the effects of low growth rates of heifers on their lifetime production of liveweight gains (LWGs) per year and per hectare (ha) subject to different management strategies. Three growth rates were imposed on grazing heifers during the growing phase (i.e. nine-36 months of age) on Brachiaria humidicola pastures. Upon the end of the previous phase, animals were allocated to a B. humidicola paddock with a reduced stocking rate or introduced to a B. decumbens sward to allow compensatory LWGs during the breeding phase (i.e. cows plus weaned calves). Severely limited heifers allowed to make compensatory growth did not reach the outputs of better fed animals. Regardless of the strategy followed, high producing years tended to be followed by lower production in the following year. Comparison with reasonably fed breeding cows full-time on well-managed B. decumbens showed important and significant differences in favor of the more intensive system over the lifetime of the animals. Over the nine-year period, the systems' beef output (i.e. weaned calves plus cows' LWGs) ranged between 86 and 206 kg/ha/year and demonstrated that a wide array of low input management alternatives is feasible. Beef output increases if the LW of cull cows is considered, particularly if they are allowed a short period of fattening during the rainy reason on a low input pasture.

RESUMEN Las novillas de reemplazo en los sistemas extensivos de cría de los Llanos Orientales de Colombia son animales de baja prioridad para el productor y generalmente se les asignan sabanas nativas o pasturas de baja calidad. Las consecuencias de dicha estrategia de manejo han sido poco investigadas. Este trabajo reunió datos de cuatro experimentos de pastoreo contemporáneos y de largo plazo para estimar el efecto de las bajas tasas de crecimiento sobre la ganancia de peso por año y por hectárea (ha) de novillas sometidas a diferentes estrategias de manejo. Se usaron tres cargas animales durante la fase de crecimiento para lograr tasas de crecimiento contrastantes entre los nueve y 36 meses de edad, con pasturas de baja calidad de Brachiaria humidicola, caracterizadas por bajo contenido de proteína bruta y baja digestibilidad. Durante la fase de cría y reproducción las novillas pasaron a pasturas de B. humidicola o de B. decumbens con cargas reducidas, para permitir ganancias de peso compensatorias. Los animales de menor ganancia durante el crecimiento no lograron ganancias compensatorias que les permitieran alcanzar a aquellos mejor alimentados. Independientemente de la estrategia de alimentación, años de relativamente alta producción fueron seguidos por años de baja producción en forma cíclica. La comparación con animales mejor alimentados con pastura de B. decumbens bien manejada, mostró diferencias considerables y significativas acumuladas durante su vida útil. A lo largo de nueve años de experimentación, la producción de ganancia de peso de vacas más terneros destetos varió entre 86 y 206 kg/ha/año, demostrando las consecuencias de largo plazo del amplio rango de estrategias de manejo experimentadas. La producción de carne en estos sistemas se puede aumentar si se le suma el peso de vacas de descarte, particularmente, si le les permite un periodo de ceba corto durante la estación lluviosa, incluso usando pasturas de calidad baja.

Assuntos

RESUMO

We aimed to evaluate the treatment with estradiol benzoate (EB) or 17ß-estradiol (E2) associated with progesterone (P4) for resynchronization of ovulation 14 days after timed artificial insemination (TAI). In Experiment 1 (Exp. 1), Nelore heifers were submitted to TAI (D0). On D14, the animals received an intravaginal P4 device and were randomly assigned to one of three groups: control (no treatment; n = 17); EB (1  mg EB; n = 17); and E2+P4 (1 mg E2 + 9 mg P4; n = 18). Ultrasonography evaluations were performed daily from D14 to D22 to map follicular and luteal dynamics. On D22, the P4 devices were removed and non-pregnant (NP) animals were determined using corpus luteum blood flow Doppler ultrasonography. In Exp. 2, 1295 beef heifers were resynchronized and randomly allocated to the same experimental groups as described in Exp. 1. On D22, the largest follicle (LF) was measured in NP and a second TAI was performed on D24. In a subset of heifers (n = 337), an estrus detection patch was used between D22 and D24 to monitor estrus expression and the LF was measured at D24. Confirmatory diagnosis of pregnancy was performed between D37-67 and D43-67 after first and second TAI, respectively. In Exp 1, the proportion of heifers with a synchronized follicular wave emergence (from 3 to 5 days after treatment) was greater (P < 0.05) in the EB group (93.8%) than in the control (62.5%) and E2+P4 (64.7%) groups. Structural luteolysis occurred earlier (P < 0.05) in the EB and E2+P4 groups than in the controls. The pregnancy rate after first TAI did not differ (P > 0.1) among the groups at D22 and at confirmatory diagnosis in both experiments. In Exp 2, the potential pregnancy loss between D22 and D37-67 was similar (P > 0.1) in the control (19% [36/185]), EB (15% [28/182]) and E2+P4 (15% [28/184]) groups. The LF diameter (mm) on D22 was greater (P < 0.05) in the control group (11.9 ± 0.1) than in EB (11.3 ± 0.1) and E2+P4 (11.5 ± 0.1). No difference (P > 0.1) was observed in the proportion of heifers detected in estrus, but LF growth rate (mm/day) between D22 and D24 was greater (P < 0.05) in EB group (0.9 ± 0.08) than in control (0.6 ± 0.07) and E2+P4 (0.7 ± 0.09) groups. The pregnancy rate for the second TAI was greater (P < 0.05) in the EB group (47% [94/200]) than in the control (37% [76/203]), but did not differ (P > 0.1) from the E2+P4 group (43% [93/214]). In conclusion, the treatment with 1 mg EB or 1 mg E2 + 9 mg P4 at 14 days post-TAI anticipates luteolysis in NP heifers but does not compromise pregnancy. The EB treatment induces a new synchronized follicle wave emergence and increases the pregnancy rate of resynchronized NP heifers.

Assuntos

RESUMO

Background: More recently, polyunsaturated fatty acids (PUFA) supplements have been used in grazing beef herds inattempt to influence specific metabolic pathways and hormones that directly modulate reproductive function. Supplementation of calcium salts of PUFA can positively influence ovarian follicular growth, luteal function, and improve reproductiveperformance in dairy and beef females. The aim of this experiment was to evaluate strategies of dietary treatments usingPUFA supplementation for 30 days before or after FTAI protocol and its effects on of ovulatory follicle size, ovulation,pregnancy and gestational losses rates in beef heifers.Materials, Methods & Results: One hundred and ninety-nine Brangus heifers (24 ± 3 months-old; BW= 320 ± 15 kg;BCS= 2.85 ± 0.17) were randomly assigned in three different groups to receive dietary treatments. Group 1 (n = 70) wasfed with 0.5 kg/day of a protein-mineral mixture supplement containing 0.2 kg/day PUFA (Mix A) during 30 days before FTAI, Group 2 (n = 68) received the same supplement 30 days after FTAI and Control (n = 61) only the supplementwithout PUFA (Mix B) during all period. Heifers were submitted to estrous synchronization treatment using progesterone(P4), estradiol benzoate (E2) and prostaglandin F2α (PGF). Ultrasound exams were done to measure ovulatory folliclediameter and to determinate ovulation and pregnancy rates on Days 30 and 60 after FTAI. Daily gain (DG) was higher (P< 0.05) only when heifers received supplement containing PUFA (Group 1= 30 days prior FTAI) and (Group 2= 30 daysafter FTAI). PUFA supplementation before FTAI also resulted in larger ovulatory follicles diameter (P < 0.05) in Group1 (11.2 ± 2.5 mm) compared to Group 2 (9.9 ± 2.3 mm) and Control (10.0 ± 2.07 mm). Ovulation rates were similar (P >0.05) in Group 1 (90%), Group 2 (75%) and Control (67%). Pregnancy rates were higher (P < 0.05) in Group 1 (Day 30=67.1% and...(AU)

Assuntos

RESUMO

Background: More recently, polyunsaturated fatty acids (PUFA) supplements have been used in grazing beef herds inattempt to influence specific metabolic pathways and hormones that directly modulate reproductive function. Supplementation of calcium salts of PUFA can positively influence ovarian follicular growth, luteal function, and improve reproductiveperformance in dairy and beef females. The aim of this experiment was to evaluate strategies of dietary treatments usingPUFA supplementation for 30 days before or after FTAI protocol and its effects on of ovulatory follicle size, ovulation,pregnancy and gestational losses rates in beef heifers.Materials, Methods & Results: One hundred and ninety-nine Brangus heifers (24 ± 3 months-old; BW= 320 ± 15 kg;BCS= 2.85 ± 0.17) were randomly assigned in three different groups to receive dietary treatments. Group 1 (n = 70) wasfed with 0.5 kg/day of a protein-mineral mixture supplement containing 0.2 kg/day PUFA (Mix A) during 30 days before FTAI, Group 2 (n = 68) received the same supplement 30 days after FTAI and Control (n = 61) only the supplementwithout PUFA (Mix B) during all period. Heifers were submitted to estrous synchronization treatment using progesterone(P4), estradiol benzoate (E2) and prostaglandin F2α (PGF). Ultrasound exams were done to measure ovulatory folliclediameter and to determinate ovulation and pregnancy rates on Days 30 and 60 after FTAI. Daily gain (DG) was higher (P0.05) in Group 1 (90%), Group 2 (75%) and Control (67%). Pregnancy rates were higher (P < 0.05) in Group 1 (Day 30=67.1% and...

Assuntos

RESUMO

The aim of this study was to evaluate the performance and feed intake of grazing beef heifers on two grazing intervals determined by thermal sum related to leaf elongation duration during cool season on natural grasslands. A complete randomized block design experiment with two treatments and three replications was conducted from May to September 2011 in the central part of the state of Rio Grande do Sul, Brazil. The treatments were two thermal sums calculated at 375 and 750 degrees-days (DD) to determine the intervals between grazing periods in a rotational grazing system. Thirty six beef heifers with average age of 18 months old and (initial body weight = 220±14kg) were used, all heifers received ground corn supplement at a rate of 5g kg-1 of body weight per day, at 2p.m., throughout the experiment and had free access to mineral and protein supplementation (450g kg-1 of CP). Similar average daily gain (ADG), beef production gain (BPG) and feed intake (FI), were obtained in both treatments. Leaf elongation duration is an alternative grazing management tool for improved animal production and to increase animal stocking rate.(AU)

Objetivou-se avaliar o desempenho e consumo de matéria seca de bezerras manejadas em pastoreio rotativo, com intervalos de pastoreio definidos por duas somas térmicas relacionadas à duração de elongação foliar de dois grupos funcionais de gramíneas durante a estação fria em pastagem natural. O delineamento experimental foi o de blocos completamente casualizados, com dois tratamentos e três repetições de área na região central do Rio Grande do Sul, Brasil. Os tratamentos foram duas somas térmicas: 375 e 750 graus-dias (GD), que determinaram os intervalos entre os pastoreios. Foram utilizadas trinta e seis bezerras de corte com idade média de 18 meses e peso corporal médio de 220±14kg. Durante todo o experimento, as bezerras receberam como suplemento grão de milho moído a uma taxa de 0,5% do peso corporal por dia, às 14:00 horas e tiveram livre acesso à suplementação proteínada (45% PB). Não houve diferença para o ganho médio diário, ganho de peso por área e consumo de matéria seca entre os tratamentos. A soma térmica como intervalo de descanso entre os pastoreios mostrou-se uma alternativa de manejo para aumentar a taxa de lotação.(AU)

Assuntos

RESUMO

ABSTRACT: The aim of this study was to evaluate the performance and feed intake of grazing beef heifers on two grazing intervals determined by thermal sum related to leaf elongation duration during cool season on natural grasslands. A complete randomized block design experiment with two treatments and three replications was conducted from May to September 2011 in the central part of the state of Rio Grande do Sul, Brazil. The treatments were two thermal sums calculated at 375 and 750 degrees-days (DD) to determine the intervals between grazing periods in a rotational grazing system. Thirty six beef heifers with average age of 18 months old and (initial body weight = 220±14kg) were used, all heifers received ground corn supplement at a rate of 5g kg-1 of body weight per day, at 2p.m., throughout the experiment and had free access to mineral and protein supplementation (450g kg-1 of CP). Similar average daily gain (ADG), beef production gain (BPG) and feed intake (FI), were obtained in both treatments. Leaf elongation duration is an alternative grazing management tool for improved animal production and to increase animal stocking rate.

RESUMO: Objetivou-se avaliar o desempenho e consumo de matéria seca de bezerras manejadas em pastoreio rotativo, com intervalos de pastoreio definidos por duas somas térmicas relacionadas à duração de elongação foliar de dois grupos funcionais de gramíneas durante a estação fria em pastagem natural. O delineamento experimental foi o de blocos completamente casualizados, com dois tratamentos e três repetições de área na região central do Rio Grande do Sul, Brasil. Os tratamentos foram duas somas térmicas: 375 e 750 graus-dias (GD), que determinaram os intervalos entre os pastoreios. Foram utilizadas trinta e seis bezerras de corte com idade média de 18 meses e peso corporal médio de 220±14kg. Durante todo o experimento, as bezerras receberam como suplemento grão de milho moído a uma taxa de 0,5% do peso corporal por dia, às 14:00 horas e tiveram livre acesso à suplementação proteínada (45% PB). Não houve diferença para o ganho médio diário, ganho de peso por área e consumo de matéria seca entre os tratamentos. A soma térmica como intervalo de descanso entre os pastoreios mostrou-se uma alternativa de manejo para aumentar a taxa de lotação.

RESUMO

The aim of this study was to evaluate the performance and feed intake of grazing beef heifers on two grazing intervals determined by thermal sum related to leaf elongation duration during cool season on natural grasslands. A complete randomized block design experiment with two treatments and three replications was conducted from May to September 2011 in the central part of the state of Rio Grande do Sul, Brazil. The treatments were two thermal sums calculated at 375 and 750 degrees-days (DD) to determine the intervals between grazing periods in a rotational grazing system. Thirty six beef heifers with average age of 18 months old and (initial body weight = 220±14kg) were used, all heifers received ground corn supplement at a rate of 5g kg-1 of body weight per day, at 2p.m., throughout the experiment and had free access to mineral and protein supplementation (450g kg-1 of CP). Similar average daily gain (ADG), beef production gain (BPG) and feed intake (FI), were obtained in both treatments. Leaf elongation duration is an alternative grazing management tool for improved animal production and to increase animal stocking rate.

Objetivou-se avaliar o desempenho e consumo de matéria seca de bezerras manejadas em pastoreio rotativo, com intervalos de pastoreio definidos por duas somas térmicas relacionadas à duração de elongação foliar de dois grupos funcionais de gramíneas durante a estação fria em pastagem natural. O delineamento experimental foi o de blocos completamente casualizados, com dois tratamentos e três repetições de área na região central do Rio Grande do Sul, Brasil. Os tratamentos foram duas somas térmicas: 375 e 750 graus-dias (GD), que determinaram os intervalos entre os pastoreios. Foram utilizadas trinta e seis bezerras de corte com idade média de 18 meses e peso corporal médio de 220±14kg. Durante todo o experimento, as bezerras receberam como suplemento grão de milho moído a uma taxa de 0,5% do peso corporal por dia, às 14:00 horas e tiveram livre acesso à suplementação proteínada (45% PB). Não houve diferença para o ganho médio diário, ganho de peso por área e consumo de matéria seca entre os tratamentos. A soma térmica como intervalo de descanso entre os pastoreios mostrou-se uma alternativa de manejo para aumentar a taxa de lotação.

Assuntos

RESUMO

The objective of this study was to determine if exposure of 2 - y ea r - old beef heifers to androgenized steers (AS) for 30 days before the beginning of an estrous synchronization protocol (ESP) and artificial insemination ( AI ) increases the estrous response and pregnancy rate . Hereford x Braford heifers were stratified by body weight and presence of a corpus luteum (CL) and assigned to be 1) e xposed to AS ( EAS ; n = 53) or 2) n o t exposed to AS ( NE ; n = 53) for 30 d ays (D ay 0 = first d ay of exposure) . Proportion s of heifers with a CL on D ay - 7 were 20.6 and 24.5% for EAS and NE , respectively. Ovaries of each heifer were scanned on Days 15 and 30 of the exposure period for a CL . On D ay 30, steers were removed from the EAS heifers and t wo doses of a PG F 2alpha analogue were administered to each heifer 11 d ays apart . Heifers were observed for behavioral estrus for 6 d ys , beginning 48 h after the last PGF 2alph a injection , and inseminated 12 h after estrus detection . More EAS than NE heifers had a CL on D ay 15 ( 5 4.7 and 32.1%, EAS and NE, respectively; P < 0.02) , but there was no difference in the proportion of heifers that had a CL by D ay 30 ( 73.6 and 72 .0 % , EA S and NE, respectively; P = 0.2 ) . There were no difference s between EAS and NE heifers for proportion s that showed estrus ( 66.0 and 67.9 % , EAS and NE, respectively ; P = 0. 8 ), conception rates ( 83 . 0 and 92 . 0 %, EAS and NE, respectively; P = 0. 3 ) and pregnancy rates ( 83 . 0 and 86.5 %, EAS and NE, respectively; P = 0. 6 ) . Exposing 2 - y ea r - old heifers to AS under the conditions of this experiment before an ESP that included a double injection of PGF 2alpha had no effects on estrous response and AI pregnancy rates.

Assuntos

RESUMO

The objective of this study was to determine if exposure of 2 - y ea r - old beef heifers to androgenized steers (AS) for 30 days before the beginning of an estrous synchronization protocol (ESP) and artificial insemination ( AI ) increases the estrous response and pregnancy rate . Hereford x Braford heifers were stratified by body weight and presence of a corpus luteum (CL) and assigned to be 1) e xposed to AS ( EAS ; n = 53) or 2) n o t exposed to AS ( NE ; n = 53) for 30 d ays (D ay 0 = first d ay of exposure) . Proportion s of heifers with a CL on D ay - 7 were 20.6 and 24.5% for EAS and NE , respectively. Ovaries of each heifer were scanned on Days 15 and 30 of the exposure period for a CL . On D ay 30, steers were removed from the EAS heifers and t wo doses of a PG F 2alpha analogue were administered to each heifer 11 d ays apart . Heifers were observed for behavioral estrus for 6 d ys , beginning 48 h after the last PGF 2alph a injection , and inseminated 12 h after estrus detection . More EAS than NE heifers had a CL on D ay 15 ( 5 4.7 and 32.1%, EAS and NE, respectively; P < 0.02) , but there was no difference in the proportion of heifers that had a CL by D ay 30 ( 73.6 and 72 .0 % , EA S and NE, respectively; P = 0.2 ) . There were no difference s between EAS and NE heifers for proportion s that showed estrus ( 66.0 and 67.9 % , EAS and NE, respectively ; P = 0. 8 ), conception rates ( 83 . 0 and 92 . 0 %, EAS and NE, respectively; P = 0. 3 ) and pregnancy rates ( 83 . 0 and 86.5 %, EAS and NE, respectively; P = 0. 6 ) . Exposing 2 - y ea r - old heifers to AS under the conditions of this experiment before an ESP that included a double injection of PGF 2alpha had no effects on estrous response and AI pregnancy rates.(AU)

Assuntos

RESUMO

Foi avaliado o desenvolvimento de bezerras de corte recebendo diferentes níveis diários de suplemento concentrado: 0,0; 0,3; 0,6 e 0,9 por cento do peso corporal em pastagem de aveia preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.). O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos e duas repetições de área. As bezerras tiveram condições similares de disponibilidade de pasto (massa de forragem e oferta de lâminas verdes) em todos os tratamentos. Aumentos na quantidade fornecida de suplemento interferiram positivamente no ganho médio diário, na carga animal, no ganho de peso por área e na eficiência de transformação da forragem. Bezerras suplementadas apresentaram maior peso corporal e maior escore de condição corporal aos 13 meses de idade em relação às não suplementadas. Em aveia preta e azevém, fornecer até 0,9 por cento do peso corporal dos animais em suplementação concentrada é uma alternativa para serem obtidas novilhas mais pesadas e com melhor escore de condição corporal.

It was evaluated the performance of beef heifers receiving different levels of supplement: 0; 0.3; 0.6 and 0.9 percent of body weight day-1, in black oats (Avena strigosa Schreb.) plus Italian ryegrass (Lolium multiflorum Lam.) pasture. The experimental design was completely randomized with four treatments and two area replicates. Beef heifers from different treatments had access to the same forage allowance (herbage mass and supply of green leaves). Increases on supplement quantity positively interfered on average daily gain, stocking rate, weight gain per area and forage transformation efficiency. Supplemented heifers had greater weight and body condition at 13 months of age than the non supplemented ones. In black oats plus Italian ryegrass pasture, providing up to 0.9 percent of body weight of the animal concentrate supplementation is an alternative for obtaining heavier heifers and in better body condition score.

RESUMO

It was evaluated the performance of beef heifers receiving different levels of supplement: 0; 0.3; 0.6 and 0.9% of body weight day-1, in black oats (Avena strigosa Schreb.) plus Italian ryegrass (Lolium multiflorum Lam.) pasture. The experimental design was completely randomized with four treatments and two area replicates. Beef heifers from different treatments had access to the same forage allowance (herbage mass and supply of green leaves). Increases on supplement quantity positively interfered on average daily gain, stocking rate, weight gain per area and forage transformation efficiency. Supplemented heifers had greater weight and body condition at 13 months of age than the non supplemented ones. In black oats plus Italian ryegrass pasture, providing up to 0.9% of body weight of the animal concentrate supplementation is an alternative for obtaining heavier heifers and in better body condition score.

Foi avaliado o desenvolvimento de bezerras de corte recebendo diferentes níveis diários de suplemento concentrado: 0,0; 0,3; 0,6 e 0,9% do peso corporal em pastagem de aveia preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.). O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos e duas repetições de área. As bezerras tiveram condições similares de disponibilidade de pasto (massa de forragem e oferta de lâminas verdes) em todos os tratamentos. Aumentos na quantidade fornecida de suplemento interferiram positivamente no ganho médio diário, na carga animal, no ganho de peso por área e na eficiência de transformação da forragem. Bezerras suplementadas apresentaram maior peso corporal e maior escore de condição corporal aos 13 meses de idade em relação às não suplementadas. Em aveia preta e azevém, fornecer até 0,9% do peso corporal dos animais em suplementação concentrada é uma alternativa para serem obtidas novilhas mais pesadas e com melhor escore de condição corporal.

RESUMO

It was evaluated the performance of beef heifers receiving different levels of supplement: 0; 0.3; 0.6 and 0.9% of body weight day-1, in black oats (Avena strigosa Schreb.) plus Italian ryegrass (Lolium multiflorum Lam.) pasture. The experimental design was completely randomized with four treatments and two area replicates. Beef heifers from different treatments had access to the same forage allowance (herbage mass and supply of green leaves). Increases on supplement quantity positively interfered on average daily gain, stocking rate, weight gain per area and forage transformation efficiency. Supplemented heifers had greater weight and body condition at 13 months of age than the non supplemented ones. In black oats plus Italian ryegrass pasture, providing up to 0.9% of body weight of the animal concentrate supplementation is an alternative for obtaining heavier heifers and in better body condition score.

Foi avaliado o desenvolvimento de bezerras de corte recebendo diferentes níveis diários de suplemento concentrado: 0,0; 0,3; 0,6 e 0,9% do peso corporal em pastagem de aveia preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.). O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos e duas repetições de área. As bezerras tiveram condições similares de disponibilidade de pasto (massa de forragem e oferta de lâminas verdes) em todos os tratamentos. Aumentos na quantidade fornecida de suplemento interferiram positivamente no ganho médio diário, na carga animal, no ganho de peso por área e na eficiência de transformação da forragem. Bezerras suplementadas apresentaram maior peso corporal e maior escore de condição corporal aos 13 meses de idade em relação às não suplementadas. Em aveia preta e azevém, fornecer até 0,9% do peso corporal dos animais em suplementação concentrada é uma alternativa para serem obtidas novilhas mais pesadas e com melhor escore de condição corporal.

RESUMO

It was evaluated the performance of beef heifers receiving different levels of supplement: 0; 0.3; 0.6 and 0.9% of body weight day-1, in black oats (Avena strigosa Schreb.) plus Italian ryegrass (Lolium multiflorum Lam.) pasture. The experimental design was completely randomized with four treatments and two area replicates. Beef heifers from different treatments had access to the same forage allowance (herbage mass and supply of green leaves). Increases on supplement quantity positively interfered on average daily gain, stocking rate, weight gain per area and forage transformation efficiency. Supplemented heifers had greater weight and body condition at 13 months of age than the non supplemented ones. In black oats plus Italian ryegrass pasture, providing up to 0.9% of body weight of the animal concentrate supplementation is an alternative for obtaining heavier heifers and in better body condition score.

Foi avaliado o desenvolvimento de bezerras de corte recebendo diferentes níveis diários de suplemento concentrado: 0,0; 0,3; 0,6 e 0,9% do peso corporal em pastagem de aveia preta (Avena strigosa Schreb.) e azevém (Lolium multiflorum Lam.). O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos e duas repetições de área. As bezerras tiveram condições similares de disponibilidade de pasto (massa de forragem e oferta de lâminas verdes) em todos os tratamentos. Aumentos na quantidade fornecida de suplemento interferiram positivamente no ganho médio diário, na carga animal, no ganho de peso por área e na eficiência de transformação da forragem. Bezerras suplementadas apresentaram maior peso corporal e maior escore de condição corporal aos 13 meses de idade em relação às não suplementadas. Em aveia preta e azevém, fornecer até 0,9% do peso corporal dos animais em suplementação concentrada é uma alternativa para serem obtidas novilhas mais pesadas e com melhor escore de condição corporal.

RESUMO

The experiment evaluated the animal response and economic return of energetic supplementation in oat (Avena strigosa Schreb) plus Italian ryegrass (Lolium multiflorum Lam) pasture. The treatments were: STP- Supplementation during the entire pasture cycle; SAS- Supplementation until the end of September and SS- No supplement. The continuous grazing system with variable stocking rate was used. The supplement utilized, with different quantities, was ground sorghum in order to maintain the same herbage mass for all treatments. Live weight daily gain was higher in STP and SAS, 0.716 and 0.710 kg, respectively than 0.580 kg in SS. The stocking rate was greater with supplements. The higher weight gain per hectare was at STP (627 kg), 75% higher than no supplement treatment, 359 kgha of LW. No significant effects on body condition score of treatments was recorded. The total cost and the net income were 775.42/165.08, 605.75/204.25 and 333.58/204.92 R$ha for STP, SAS and SS, respectively. No supplements and the use of supplementation until the end of September resulted in higher economic return.

O experimento avaliou a resposta animal e o retorno econômico do uso da suplementação energética em pastagem de aveia preta (Avena strigosa Schreb) + azevém anual (Lolium multiflorum Lam). Os tratamentos foram: STP - Suplementação, durante todo o período de utilização da pastagem; SAS- Suplementação até final de setembro; SS- Sem suplementação. O sistema de pastejo foi o contínuo com lotação variável. O suplemento utilizado foi o grão de sorgo em quantidade variável para manter a mesma quantidade de massa de forragem em todos os tratamentos. O ganhos de peso médios diários por animal (GMD) foram superiores nos tratamentos STP e SAS, 0,716 e 0,710 kg, respectivamente, em relação ao obtido no tratamento SS (0,580 kg). A suplementação possibilitou maior carga animal. A produção animal por hectare foi maior em STP, 627 kg ha-1 de PV, sendo 75% superior aos 359 kg ha-1 de PV do SS. A suplementação não afetou a condição corporal dos animais. O custo total e a receita líquida foram de 775,42/165,08, 605,75/204,25 e 367,35/204,92 R$ ha-1 para STP, SAS e SS, respectivamente. O uso exclusivo da pastagem e a suplementação, até o final de setembro, resultaram em maior retorno financeiro direto.

RESUMO

The experiment evaluated the animal response and economic return of energetic supplementation in oat (Avena strigosa Schreb) plus Italian ryegrass (Lolium multiflorum Lam) pasture. The treatments were: STP- Supplementation during the entire pasture cycle; SAS- Supplementation until the end of September and SS- No supplement. The continuous grazing system with variable stocking rate was used. The supplement utilized, with different quantities, was ground sorghum in order to maintain the same herbage mass for all treatments. Live weight daily gain was higher in STP and SAS, 0.716 and 0.710 kg, respectively than 0.580 kg in SS. The stocking rate was greater with supplements. The higher weight gain per hectare was at STP (627 kg), 75% higher than no supplement treatment, 359 kgha of LW. No significant effects on body condition score of treatments was recorded. The total cost and the net income were 775.42/165.08, 605.75/204.25 and 333.58/204.92 R$ha for STP, SAS and SS, respectively. No supplements and the use of supplementation until the end of September resulted in higher economic return.

O experimento avaliou a resposta animal e o retorno econômico do uso da suplementação energética em pastagem de aveia preta (Avena strigosa Schreb) + azevém anual (Lolium multiflorum Lam). Os tratamentos foram: STP - Suplementação, durante todo o período de utilização da pastagem; SAS- Suplementação até final de setembro; SS- Sem suplementação. O sistema de pastejo foi o contínuo com lotação variável. O suplemento utilizado foi o grão de sorgo em quantidade variável para manter a mesma quantidade de massa de forragem em todos os tratamentos. O ganhos de peso médios diários por animal (GMD) foram superiores nos tratamentos STP e SAS, 0,716 e 0,710 kg, respectivamente, em relação ao obtido no tratamento SS (0,580 kg). A suplementação possibilitou maior carga animal. A produção animal por hectare foi maior em STP, 627 kg ha-1 de PV, sendo 75% superior aos 359 kg ha-1 de PV do SS. A suplementação não afetou a condição corporal dos animais. O custo total e a receita líquida foram de 775,42/165,08, 605,75/204,25 e 367,35/204,92 R$ ha-1 para STP, SAS e SS, respectivamente. O uso exclusivo da pastagem e a suplementação, até o final de setembro, resultaram em maior retorno financeiro direto.

RESUMO

The experiment evaluated the use of injectable additives known as "organic modifiers", containing minerals, vitamins and amino acids on the weight gain of yearling beef heifers when kept on adequate or limited nutritional conditions. The results showed that the injection of additives did not affect the daily weight gain of beef heifers when kept on limited (native pasture) or on adequate (cultivated pasture) nutritional conditions.  

O experimento teve como objetivo, estudar a eficiência dos produtos comercializados sob a denominação "modifica-dores orgânicos" no desenvolvimento de novilhas. Esses produtos, formulados à base de aminoácidos, vitaminas e, minerais, com indicações como estimulante das funções orgânicas, revigorante e reconstituinte, vem apresentando utilização crescente por produtores rurais, visando à aceleração do crescimento ou a redução das perdas de peso no período de escassez de alimentos (inverno). Foram testadas duas marcas comerciais de modificadores orgânicos em novilhas de sobreano mantidas em condições de campo nativo e em pastagem cultivada de inverno. Verificou-se que os produtos, testados e comercializados como modificadores orgânicos, não afetaram o ganho de peso dos animais, tanto em condições limitantes (campo nativo) como em condições adequadas (pastagem cultivada) de alimentação.    

RESUMO

The experiment evaluated the use of injectable additives known as "organic modifiers", containing minerals, vitamins and amino acids on the weight gain of yearling beef heifers when kept on adequate or limited nutritional conditions. The results showed that the injection of additives did not affect the daily weight gain of beef heifers when kept on limited (native pasture) or on adequate (cultivated pasture) nutritional conditions.

O experimento teve como objetivo, estudar a eficiência dos produtos comercializados sob a denominação "modifica-dores orgânicos" no desenvolvimento de novilhas. Esses produtos, formulados à base de aminoácidos, vitaminas e, minerais, com indicações como estimulante das funções orgânicas, revigorante e reconstituinte, vem apresentando utilização crescente por produtores rurais, visando à aceleração do crescimento ou a redução das perdas de peso no período de escassez de alimentos (inverno). Foram testadas duas marcas comerciais de modificadores orgânicos em novilhas de sobreano mantidas em condições de campo nativo e em pastagem cultivada de inverno. Verificou-se que os produtos, testados e comercializados como modificadores orgânicos, não afetaram o ganho de peso dos animais, tanto em condições limitantes (campo nativo) como em condições adequadas (pastagem cultivada) de alimentação.