Marcelo Alves Pimentel

Produção de Carne em Cordeiros Cruza Border Leicester com Ovelhas Corriedale e Ideal

O estudo objetivou oferecer informacoes sobre a morfologia (in vivo e na carcaca), caracteristicas comerciais, componentes do peso vivo, qualidade da carcaca e da carne em cordeiros nao castrados cruzas de Border Leicester com ovelhas Corriedale e Ideal, criados em condicoes de campo nativo no Rio Grande do Sul, Brasil. Foram utilizados 24 cordeiros, 11 procedentes do cruzamento de Border x Corriedale e 13 de Border Leicester x Ideal, sacrificados com 6,5 meses de idade. Foi verificado um efeito entre os cruzamentos para a perda ao resfriamento (em kg e %), peso e percentagem da pele, peso e percentagem do pescoco e capacidade de retencao de agua. Igualmente, foi verificado que ha diferenca no desenvolvimento relativo dos componentes do peso vivo, composicao regional da carcaca e composicao tecidual da paleta entre os cordeiros Border Leicester x Corriedale e Border Leicester x Ideal e, dentro de cada genotipo verificou-se uma diferenca quantitativa e qualitativa entre a paleta e a perna. As diferenca quanto a qualidade da carcaca e carne nao apresentam importância pratica que justifique uma diferenciacao do produto; porem, a comercializacao deve ser com base no peso de carcaca fria e nao com base no peso vivo ou carcaca quente. A paleta e mais precoce que a perna em ambos grupos geneticos.

Componentes do peso vivo em cordeiros da raça Corriedale

In order to obtain subsidies to a retail system based on the whole animal, this study compares the weight of live components of lambs, male (castrated) and female, of the Corriedale breed, at three different slaughter ages. Animais were raised under range conditions on native pasture, at Acegua region, Bage county in southern Brazil. Sixteen lambs (60) bom in August 1994 and slaughtered twenty at a time (10 males + 10 females), choosing always the heaviest ones, at the following ages: 03/04/95, 08/05/95 and 05/05/95. There was a siaughtering time effect upon live weight and its components. In absoluto values (kg) slaughtering time influenced live weight, carcass weight, green viscera, head, legs, lungs with trachea, hearth and kidneys. It carne out that animais slaughtered in the first group (April) showed a heavier live and carcass weight than those slaughtered in the second group (May) and these were heavier than the ones slaughtered in the third group (June). The heaviest lambs, with exception of the hearth, showed higher weights of their body components. There was a sex effect too, upon live weight, green viscera, head, legs, tiver and kidneys. In either, absoluto or percentile values, males were heavier than females. It is concluded that slaughter time and sex of the individuais are elements to be considered to obtain uniform carcasses. an importam aspect to retail and acceptance by the consumer.

Características da lactação de vacas Hereford criadas em um sistema de produção extensivo na região da campanha do Rio Grande do Sul

Milk yield of primiparous and multiparous Hereford cows grazing native pastures was studied using 144 lactations from four different years (1995, 1998, 2000, 2001). Estimates of milk yield were obtained every 21-day interval from birth to weaning (189 d) by the weigh-suckle-weigh technique. Effects of year, calving order, pregnancy, calf sex, and sire breed were studied. Multiparous cows (8.27+0.26 kg/d) yielded more milk than primiparous cows (5.81+0.25 kg/d) at peak of lactation (42 d). Total milk yield also was higher for multiparous (1,158.34+25.51 kg/d) compared to primiparous (915.44+24.47 kg/d). Therefore, the main difference between multiparous and primiparous lactation curves was production at peak although similar lactation persistence was found. All remaining effects did not affect milk yield in the present trial. Milk met calf requirements for maintenance and growth in the first 2 months of lactation and only maintenance requirements until the fourth month.

Produção de leite e desempenho pós parto de vacas Hereford em distintas condições reprodutivas criadas extensivamente

Milk production and pospartum performance from 52 multiparous Hereford cows, with the same body condition score (3 in a 1 to 5 scale), pregnant (45) or not pregnant (24), was studied in 69 lactations during two years, 2000 (42) and 2001 (27) under range conditions. Estimates of milk yield were obtained during six intervals (three 21d and three 42d), by the weigh-suckle-weigh technique, from birth to weaning (189d). Effects studied were year, pregnancy, calf sex and sire breed. None of the effects studied affected (P>0.05) milk production parameters: daily milk production, total milk yield, lactation peak and persistency. Body weight at calving was greater (P<0.05) in 2001 (417.49 ± 6.94kg) that in 2000 (353. 97 ± 5.57kg) and was not affected by the other effects. Body weight at conception (99d; 432.10 ± 5.78 and 399,37 ± 7.92kg) and at weaning (189d; 433.30 ± 6.36 and 393.46 ± 8.70kg), were greater (P<0.05) in pregnant cows than in non-pregnant animals, respectively. Sex of calf had a significant effect (P<0.05) on calf birth weight (41.75 ± 1.21kg and 37.6 ± 1.13kg for males and females, respectively). All studied effects affected significantly calf weaning weight (P<0.05) and pregnant cows had heavier calves at weaning (194.22 ± 3.41kg) than non-pregnant cows (177.43 ± 4.67kg). The greatest performance of pregnant beef cows with similar milk yield and body condition score from calving to weaning can be explained by the superior adaptation characteristics of these cows.

Postpartum reproductive performance of beef cows in moderate body condition submitted to estrus induction/synchronization

To assess the reproductive performance of beef cows submitted to estrus induction/synchronization, 42 Aberdeen Angus cows with body condition 3 (1-5 scale) under extensive management were used. The milk production was estimated through the weight-suckling-weight method. For gynecological examinations, ultrasound equipment and trans-rectal palpation were used. The milk production level (above and below the average production of cows), pregnancy, prebreeding reproductive condition (CRPA), surface anoestrus (uterine tone, follicles > 10 mm and absence of CL) and deep anoestrus (no uterine tone, follicles <10 mm and absence of CL) and the estrus induction/synchronization response (RISC) were considered as constant factors. The variables analyzed were the pre-delivery, delivery weight, mating and conception weights, weaning weight, the average daily weight gain from birth to weaning and total milk production. The prebreeding reproductive condition influenced the pre-birth and birth weights, showing that the better pre-birth and birth performance favors the restoration of reproductive activity in cows with moderate body condition (CC) in the post-partum period. The classification of the pre-breeding reproductive condition in beef cows can be a resource to determine the reproductive performance of beef cows submitted to estrus induction/synchronization, since cows in surface anoestrus tend to have better response to the protocol. In beef cows with moderate body condition, the pre-birth weight performance affects the prebreeding reproductive condition, increasing the likelihood of better reproductive performance.To assess the reproductive performance of beef cows submitted to estrus induction/synchronization, 42 Aberdeen Angus cows with body condition 3 (1-5 scale) under extensive management were used. The milk production was estimated through the weight-suckling-weight method. For gynecological examinations, ultrasound equipment and trans-rectal palpation were used. The milk production level (above and below the average production of cows), pregnancy, prebreeding reproductive condition (CRPA), surface anoestrus (uterine tone, follicles > 10 mm and absence of CL) and deep anoestrus (no uterine tone, follicles <10 mm and absence of CL) and the estrus induction/synchronization response (RISC) were considered as constant factors. The variables analyzed were the pre-delivery, delivery weight, mating and conception weights, weaning weight, the average daily weight gain from birth to weaning and total milk production. The prebreeding reproductive condition influenced the pre-birth and birth weights, showing that the better pre-birth and birth performance favors the restoration of reproductive activity in cows with moderate body condition (CC) in the post-partum period. The classification of the pre-breeding reproductive condition in beef cows can be a resource to determine the reproductive performance of beef cows submitted to estrus induction/synchronization, since cows in surface anoestrus tend to have better response to the protocol. In beef cows with moderate body condition, the pre-birth weight performance affects the prebreeding reproductive condition, increasing the likelihood of better reproductive performance.

Época de nascimento, genótipo e sexo de terneiros cruzas taurinos e zebuínos sobre o peso ao nascer, à desmama e eficiência individual de primíparas Hereford

The objective of the present study was to evaluate the effect of calving season, genotype and calf sex on the cows weaning individual efficiency ( percentual relationship between cow body weight and calf weaning weight), birth and weaning weight of calves. Forty-eight primiparous Hereford cows with approximate average age of 3 years and grazing only native pastures were used. Sixteen inseminated with one Red Angus bull (Bos taurus) and 32 with Nelore (Bos indicus). Effects studied were calf genotype (GENOT), Bos taurus x Bos taurus and Bos taurus x Bos indicus, calving season (EPOCN) concentrated in the Spring and subdivided into three periods: 1S (September), 2O (October) and 3N (November and December) and calf sex (SEXO). Milk production (PL) was included as co-variable. Ten measurements of milk production obtained by the indirect method, weighing the calf before and after suckling, and eleven measurements of cow and calf weights, were made at 21 day intervals. Effects with significant influence on PN were GENOT and SEXO (P<0.05). P205 was significantly affected by EPOCN, SEXO and PL (P<0.05). EI was significantly affected by EPOCN, SEXO and PL until 147 days (P<0.05). Calf genotype and sex affected their birth weight. Weaning weight and cow efficiency are affected by sex and and calving season, but not by calf genotype.

Methods of inducing conditioned food aversion to Baccharis coridifolia (mio-mio) in cattle

Foram realizados tres experimentos para determinar a eficacia de varios metodos de aversao a Baccharis coridifolia em bovinos: administracao oral forcada de 0,5g kg-1 de peso vivo de B. coridifolia fresca; inalacao forcada da fumaca proveniente da queima de B. coridifolia e esfregacao da planta no focinho e na boca dos animais; e introducao dos animais em pastagens com baixa infestacao por B. coridifolia. Os resultados demonstraram que os animais forcados a ingerir pequenas doses tornaram-se fortemente avertidos, quando introduzidos nos piquetes entre 23 a 26 horas apos a aversao. Entretanto, bovinos introduzidos nos piquetes apos 1 a 10 horas nao foram totalmente avertidos. Inalacao da fumaca de B. coridifolia e esfregacao da planta no focinho e boca dos animais nao foram eficientes para produzir aversao. A introducao de bovinos em piquetes com aproximadamente 1% de B. coridifolia foi eficiente quando os animais permaneceram cinco meses na area, mas nao quando ficaram apenas 60 horas, pois os bovinos precisam de tempo para aprender a evitar a planta.

Effect of short period feed supplementation during early lactation on performance of cows and calves raised in extensive system

Thirty-two multiparous Angus cows at moderate body condition score (3 in a 1-5 scale) received feed supplementation at the beginning of lactation for a short time to determine the effect on milk yield and composition and on performance of cows and calves. Supplementation started on days 22 ± 3.2 after calving. The cows were randomly distributed into two groups (n =16), one group receiving feed supplementation for 35 days (supplemented group), and the other without supplementation (control group). Each cow received 0.6% of its body weight in individual troughs daily. Both groups were kept in native pasture condition during supplementation period. Milk yield evaluation, performance of cows and calves were controlled on day 0 (initial), day 14 (middle) and day 35 (final) of the supplementation period. There was no effect of feed supplementation on milk yield or on any other milk component in both groups, and on calf performance as well. Milk composition differed among periods, when fat was the highest in the middle of supplementation and lactose was the highest in the end of the period. Supplemented cows presented more daily average weight gain at the final period of supplementation than cows from the control group. Beef cow with moderate body condition score can gain weight during the lactation period as a response to increase of energy availability in a short period without any influence on milk production and composition as well as a consequence on calf performance.

Disponibilidade de energia líquida no leite e desempenho ponderal de bezerros Hereford e Aberdeen Angus do nascimento à desmama

This research aimed at evaluating ponderal performance of the calves from birth to 189 days of age. Ninety-five calves were used (55 Aberdeen Angus and 40 Hereford), grazing natural pasture. Milk production of cows was estimated by the weight-suckled-weight method, and ponderal performance of the calves was evaluated in 21-day intervals from birth. Calving season was divided at time 1 (September) and time 2 (October). For analyses, it was included in the statistical model as fixed effects, breed of the cows, calf sex in the calving season, calving order and pregnancy. Data were submitted to statistical analyses, adopting 0.5 as critical levels of probability. Breed of the dams influenced calves weaning weight, average daily weight gain and cow efficiency, with 191.90 and 163.02 kg, 0.78 and 0.64 kg, and, 45.24 and 39.40%, for Aberdeen Angus and Hereford, respectively. Multiparous cows were superior to primiparous on weight of the calves on birth and on weaning on average daily weight gain. Calving season affected weights of the calves on birth and on weaning, average daily weight gain and total milk production with the following values for September and October: 31.15 and 37.19 kg; 183.63 and 171.29 kg; 0.76 and 0.67 kg; and, 1,605.04 and 1,378.78 kg, respectively. September was the best time for calf weight at weaning, average daily weight gain and total milk production, while October was better only for birth weight. Performance of calves is not influenced by their sex neither by pregnancy.

Desempenho reprodutivo de vacas de corte em lactação e solteiras submetidas à indução/sincronização de estro

Com o objetivo de caracterizar o desempenho produtivo e reprodutivo de duas categorias de vacas de corte submetidas a inducao/sincronizacao de estro, foram utilizadas 42 vacas em lactacao e 60 vacas solteiras da raca Aberdeen Angus, de tamanho similar e condicao corporal moderada (CC3, escala de 1 a 5), manejadas exclusivamente em campo nativo, no periodo de setembro de 2005 a abril de 2006 no municipio de Acegua/RS. Para os exames ginecologicos durante o experimento, foi utilizado aparelho de ultra-som e palpacao retal. Como fator fixo, foi considerada a categoria das vacas (CATV), considerando-se tres grupos, vacas solteiras ciclicas (VSC), ou seja, femeas que falham em conceber e permanecem na propriedade ate o proximo acasalamento, vacas em lactacao em anestro superficial (VLAS) e vacas em lactacao em anestro profundo (VLAP). Como variaveis resposta, foram considerados peso das vacas pre-acasalamento (PPRA), pos-acasalamento (PPOA), a concepcao (PC), o ganho de peso medio diario durante o acasalamento (GMD), resposta ao protocolo de inducao/sincronizacao de cio (RISC) e gestacao. A categoria da vaca demonstrou efeito (P<0,0001) sobre as variaveis de peso, em que as VSC apresentaram um melhor desempenho ponderal do que VLAS e VLAP. A RISC demonstrou ser altamente influenciada (P<0,0001) pela categoria de vaca, em que 85, 45 e 35% das vacas responderam a inducao/sincronizacao de cio nos grupos VSC, VLAS e VLAP, respectivamente. A gestacao apresentou diferenca (P<0,0001) entre VSC e vacas em lactacao, com 96,7, 45,5 e 30,0%, nos respectivos grupos VSC, VLAS e VLAP. Vacas solteiras apresentam um desempenho reprodutivo superior ao de vacas em lactacao, evidenciado pela maior resposta ao protocolo de inducao/sincronizacao de estro e indice de gestacao. Contudo, 24% das vacas em lactacao parecem estar bem adaptadas ao sistema de producao, demonstrando um desempenho produtivo e reprodutivo satisfatorio a producao de bovinos de corte, sendo capazes de produzir adequadamente leite para o desenvolvimento dos terneiros, bem como conceber e produzir novamente um terneiro. A identificacao desses animais pode influenciar positivamente o desempenho reprodutivo de vacas de corte em lactacao.