RESUMO
The objective was to evaluate the effect of cow genetic group, nutritional level and their interaction on some economically important traits of dual-purpose herds managed under field conditions. Nine herds were monitored during a production cycle in Yucatan, Mexico. Herds were grouped into four nutritional levels (NL) based on the metabolizable energy (ME) apparently available on pasture, nutritional management, and milk production. Cows were classified into three genetic groups (GG): low (< or = 25%), middle (25-75%) and high (> or = 75%) graded for Bos taurus inheritance. Total milk sold (TMS), days in milk (DIM), TMS adjusted to DIM within each NL (TMSA), body condition score (BCS) at calving, changes of BCS during lactation (CBCS), calf weaning weight (WW), age at weaning (AW), kg of calf weaned per cow (KWC) and calf mortality were studied. The statistical model included the fixed effects of NL, GG, month of calving (MC), parity number (PN) and BCS at calving and GG x NL interaction. The effects of NL, GG, MC, PN and GG x NL were significant (p < 0.05) for TMS, KWC. As expected, TMS increased with NL from 562.4 +/- 106 kg for NL1 to 2366.3 +/- 100.1 kg for NL4. KWC was greatest for NL2 (138.6 kg) followed by NL1 (135 kg); the lowest KWC corresponded to NL4 (96.0 kg) (p < 0.05). TMS values for the middle (1727 +/- 94.7 kg) and the high graded GG (1603.5 +/- 83.5 kg) were twice those for the low graded GG cows (828.5 +/- 95 kg) (p < 0.05). KWC was also higher for the middle graded group (152.8 kg) than for the low or (104 kg) or the high graded GG (118 kg) (p < 0.05). With better nutrition cows of all GG improved their milk performance but not the calf traits. CBCS was negative for all GG. The highest BCS lost was for cows in NL1 and NL2 and for cows in the high graded GG (p < 0.05).
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Bovinos/genética , Bovinos/fisiologia , Lactação/genética , Reprodução/genética , Animais , Composição Corporal/genética , Composição Corporal/fisiologia , Cruzamentos Genéticos , Metabolismo Energético/fisiologia , Feminino , Lactação/fisiologia , Masculino , Mastite Bovina/epidemiologia , Mastite Bovina/genética , México , Leite/metabolismo , Paridade , Gravidez , Reprodução/fisiologiaRESUMO
Avaliou-se a distribuição de Lawsonia intracellularis em fezes de suínos, coletadas diretamente no reto, durante a fase de crescimento/terminação, sob condições de campo, e determinou-se o efeito da infecção L. intracellularis no ganho de peso. O estudo epidemiológico longitudinal foi desenvolvido em uma granja de múltiplos sítios em Yucatan, México. A granja possuía três sítios geograficamente isolados com o sistema "todos dentro todos fora". Uma amostra de 56 suínos negativos para a bactéria foi calculada utilizando prevalência esperada de 5%, nível de confiança de 95% e população de 2000 suínos terminados. Os suínos foram amostrados 12 vezes desde o nascimento até a 23ª semana de idade. A detecção de DNA bacteriano nas fezes pela técnica de reação em cadeia pela polimerase em qualquer coleta representou um caso. Dos 56 suínos monitorados, 13 eliminaram L. intracellularis nas fezes e somente um resultou positivo duas vezes. A eliminação de L. intracellularis foi detectada desde a terceira até a 19ª semana de idade, observando-se maior número de animais positivos na 11ª semana. A incidência acumulada e a taxa de incidência foram 23,2% e 1,21 suínos por 100 animais/semana em risco, respectivamente. As médias do ganho de peso por dia foram 0,742±0,06kg e 0,754±0,07kg para os suínos negativos e positivos, respectivamente (P>0,05). A eliminação da bactéria ocorreu durante todo o período de estudo. Pelo menos neste estudo, L. intracellularis não pode ser utilizado para predizer o efeito da bactéria sobre o ganho de peso.(AU)
Assuntos
Animais , Enteropatias/epidemiologia , Reação em Cadeia da Polimerase , Reação em Cadeia da Polimerase/métodos , Lawsonia (Bactéria)/isolamento & purificação , Suínos , Aumento de PesoRESUMO
Avaliou-se a distribuição de Lawsonia intracellularis em fezes de suínos, coletadas diretamente no reto, durante a fase de crescimento/terminação, sob condições de campo, e determinou-se o efeito da infecção L. intracellularis no ganho de peso. O estudo epidemiológico longitudinal foi desenvolvido em uma granja de múltiplos sítios em Yucatan, México. A granja possuía três sítios geograficamente isolados com o sistema "todos dentro todos fora". Uma amostra de 56 suínos negativos para a bactéria foi calculada utilizando prevalência esperada de 5 por cento, nível de confiança de 95 por cento e população de 2000 suínos terminados. Os suínos foram amostrados 12 vezes desde o nascimento até a 23ª semana de idade. A detecção de DNA bacteriano nas fezes pela técnica de reação em cadeia pela polimerase em qualquer coleta representou um caso. Dos 56 suínos monitorados, 13 eliminaram L. intracellularis nas fezes e somente um resultou positivo duas vezes. A eliminação de L. intracellularis foi detectada desde a terceira até a 19ª semana de idade, observando-se maior número de animais positivos na 11ª semana. A incidência acumulada e a taxa de incidência foram 23,2 por cento e 1,21 suínos por 100 animais/semana em risco, respectivamente. As médias do ganho de peso por dia foram 0,742±0,06kg e 0,754±0,07kg para os suínos negativos e positivos, respectivamente (P>0,05). A eliminação da bactéria ocorreu durante todo o período de estudo. Pelo menos neste estudo, L. intracellularis não pode ser utilizado para predizer o efeito da bactéria sobre o ganho de peso.
Assuntos
Animais , Enteropatias/epidemiologia , Lawsonia (Bactéria)/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase , Suínos , Aumento de PesoRESUMO
Information on 936 birth weights (BW), adjusted weaning weights (AWW) and average daily gains (ADG) from Brahman (B), Indubrazil (I), Gyr (G) and commercial Zebu (C) cattle and their crosses were obtained from the records of a farm in the State of Yucatan, Mexico. Two statistical models were used to analyse the data: the first included the effects of year and season of birth, sex of the calf, cow's parity number and breed group. The other model included the same environmental effects as the previous model and the genetic components of breed group (breed additive, breed maternal and heterosis effects). Additive and maternal effects were expressed as deviations from those for the B breed. The means of BW. AWW and ADG for the B breed were 33.3 +/- 0.64 kg, 204.0 +/- 4.9 kg and 760.06 +/- 19.24 g/day, respectively. Both models gave similar results in terms of the variance explained. Additive effects were significant (p < 0.05) for AWW and ADG but not for BW. The minor additive effect was for the C breed (-10.75 kg and 40.77 g for WW and ADG, respectively). Maternal and heterosis effects were not significant (p > 0.05) for any of the traits. The correlation between the breed group means and the means estimated by the prediction equation was r = 0.88. Finally, there was no significant genetic effect on pre-weaning calf performance among the genotypes evaluated. The genetic model can be used to predict the genotype means with a high degree of accuracy.
Assuntos
Cruzamento/métodos , Bovinos/fisiologia , Cruzamentos Genéticos , Animais , Animais Recém-Nascidos , Peso ao Nascer/genética , Bovinos/genética , Feminino , Vigor Híbrido , Masculino , Modelos Genéticos , Modelos Estatísticos , Gravidez , Aumento de Peso/genéticaRESUMO
A cross-sectional epidemiologic study was conducted in order to detect the presence of and to estimate the seroprevalence of Oestrus ovis L. infection in flocks of sheep from the central region of the state of Yucatan, Mexico. The risk factors associated with disease were also identified. A sample size of 10 animals per farm was used to detect seropositive animals, considering a 30% prevalence and 95% confidence level. Blood samples of 689 sheep from 88 flocks were collected and a questionnaire with questions about the flock and the host was applied. The thin layer immune assay test was used. The risk factors were screened using logistic regression procedures. 77% of the flocks had at least one-positive animal with antibodies against O. ovis. The overall seroprevalence and standard error was 30.6 +/- 3.5%. Only flock size and sheep nose color showed association (P < 0.05) with the disease. The odds ratios for flocks with less than 11 and with 11 to 25 sheep, as related to herds with 25 or more sheep, were 0.74 and 1.73, respectively. Sheep with dark noses had a higher risk (OR = 1.46) compared with sheep having light noses (P < 0.05).
Assuntos
Dípteros/crescimento & desenvolvimento , Miíase/veterinária , Doenças dos Ovinos/epidemiologia , Fatores Etários , Animais , Anticorpos/sangue , Estudos Transversais , Dípteros/imunologia , Feminino , Imunoensaio/veterinária , Modelos Logísticos , Masculino , México/epidemiologia , Miíase/epidemiologia , Razão de Chances , Pigmentação , Fatores de Risco , Estudos Soroepidemiológicos , Fatores Sexuais , Ovinos , Doenças dos Ovinos/parasitologia , Inquéritos e Questionários , Clima TropicalRESUMO
Chicken mortality was studied in 24 randomly selected smallholder flocks in one village in Yucatan, Mexico between July and December 1993. Each family received a package of 10 to 12 chicks of 3 weeks of age. Approximately half of the chicks were purebred and the remainder were crosses produced by mating exotic with local breeds. All smallholders were visited twice a week. Feeding and management (except vaccination and medication) were left to smallholders. Data were processed by Chi-square, Mantel-Haenzel test and survival analysis. Before reaching 140 days of age 43.2% of the birds died. The highest mortality was observed during the 113 to 140 days of age period and the lowest was in the period between 22 and 56 days of age. Of all birds, 10.5% died from coccidiosis and 7.6% from Marek's disease. Of the risk factors investigated only medication and genotype showed significant effects on mortality. The effect of genotype was significant up to 112 days of age (P < 0.05). Crossbred birds lived longer than purebred; independently, medicated birds lived longer than non-medicated birds.
Assuntos
Criação de Animais Domésticos/métodos , Cruzamento , Galinhas/genética , Doenças das Aves Domésticas/mortalidade , Animais , Coccidiose/epidemiologia , Coccidiose/mortalidade , Coccidiose/veterinária , Feminino , Genótipo , Masculino , Doença de Marek/epidemiologia , Doença de Marek/mortalidade , México/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Fatores de Risco , Estatística como Assunto , Taxa de SobrevidaRESUMO
Information for this study was obtained from a commercial beef enterprise located in the subhumid tropics of Yucatan, Mexico. Data from 664 females of different zebu breeds born from 1972 to 1983 were considered for analyses. Weaning and 18-month weights were adjusted to 240 (W240) and to 550 (W550) days of age, respectively. The statistical model included the fixed effects of years of birth, season of birth, age of dam at calving, breed of heifer and the random effect of sire within breed. Arithmetic mean +/- standard deviations were 32.1 +/- 3.6 kg, 208.3 +/- 29.1 kg, 678.1 +/- 94.6 g, 308.7 +/- 29.7 kg, 342.3 +/- 89.8 g and 1,060.2 +/- 118.7 days for birth weight (BW), W240, average preweaning daily gain (ADG), W550 postweaning daily gain (PDG) and age at first calving (AFC), respectively. Year and season of birth had significant (P < 0.05) effects on W240, ADG, W550, PDG and AFC. Parity number was significant (P < 0.05) for BW, W240, ADG and AFC. Breed differences were significant (P < 0.01) for all traits, except BW. Guzerat heifers were heavier at weaning and W550 than heifers from the other breeds. Guzerat heifers first calved at an average age of 995 days; Brahman and commercial zebu heifers calved about 50 to 60 days later and the Indubrazil and Gyr heifers about 2 months later still. The heritability estimates were 0.24 +/- 0.13 for BW, 0.26 +/- 0.14 for W240, 0.29 +/- 0.14 for ADG, 0.43 +/- 0.17 for W550, 0.56 +/- 0.20 for PDG and 0.46 +/- 0.15 for AFC.
Assuntos
Envelhecimento/genética , Cruzamento , Bovinos/crescimento & desenvolvimento , Bovinos/genética , Paridade/fisiologia , Envelhecimento/fisiologia , Análise de Variância , Animais , Bovinos/fisiologia , Feminino , México , Modelos Estatísticos , Estações do Ano , Fatores de Tempo , Aumento de Peso/fisiologiaRESUMO
Data on 4,754 lambs born from Pelibuey (PB) and Barbados Blackbelly (BB) ewes collected over 9 years at the Mococha Experimental Centre in Yucatan, Mexico, were used to determine environmental, dam-breed and sire-breed effects on birth weight (BW), weaning weight (WW) and average daily gain (ADG). Effects of year and season of birth, sex of the lamb, type of birth, breed of dam, breed of sire, their interaction and ewe body weight were included. Heritabilities were estimated for each breed. Season of lambing was a significant source of variation on WW and ADG. Male lambs weighed more than female lambs at birth and weaning. Single born lambs were heavier than twins and triplets. Lambs born from PB dams were heavier and grew faster than those born from BB dams. Heritabilities of BW, WW and ADG for the PB breed were 0.16 +/- 0.04, 0.12 +/- 0.03 and 0.11 +/- 0.03, respectively and 0.04 +/- 0.07, 0.17 +/- 0.09 and 0.15 +/- 0.08 for the BB breed. Heterosis values were close to zero.
Assuntos
Peso Corporal/genética , Ovinos/genética , Animais , Peso ao Nascer/genética , Cruzamento , Feminino , Masculino , México , Estações do Ano , Ovinos/crescimento & desenvolvimento , Desmame , Aumento de Peso/genéticaRESUMO
Paracoccidioidomycosis (South American blastomycosis) is a severe deep mycosis that begins in the lungs, mouth and pharynx and can affect the whole organism through lymphatic and hematologic dissemination. It is caused by the fungus Paracoccidioides brasiliensis and occurs in warm and humid regions near large forest. The sulfonamides are very active and represent the therapy of choice. Special cases are treated with Amphotericin B.