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This study aimed to evaluate the effects of direct-fed microbials (DFM) on health and growth responses of preweaning Bos indicus × Bos taurus (Gyr × Holstein) crossbred calves. Ninety newborn heifer calves (initial BW of 35 ± 4.0 kg) were used. At birth, calves were ranked by initial BW and parity of the dam and assigned to: (1) whole milk without DFM supplementation (CON; n = 30), (2) whole milk with the addition of 1.0 g/calf per day of a Bacillus-based DFM (BAC; n = 30), or (3) whole milk with the addition of 1.0 g/calf per day of BAC and 1.2 g/calf per day of Enterococcus faecium 669 (MIX; n = 30). Milk was fed individually during the study (77 d), and the BAC and MIX treatments were offered daily throughout the 77-d preweaning period. All calves were offered a starter supplement and corn silage starting on d 1 and 60 of age, respectively. Milk and starter supplement intake were evaluated daily, and BW was recorded on d 0 and at weaning (d 77). Diarrhea and pneumonia were assessed daily, and fecal samples were collected on d 0, 7, 14, 21, and at weaning (d 77) for assessment of the presence of bacterial and protozoal pathogens via qPCR. All data were analyzed using SAS (v. 9.4) with calf as the experimental unit and using single-df orthogonal contrasts (BAC + MIX vs. CON; BAC vs. MIX). Daily feeding of DFM, regardless of type, improved weaning BW. Odds ratio for occurrence of pneumonia was lower for DFM-supplemented calves, but its occurrence did not differ between BAC and MIX calves. No Salmonella spp. or Escherichia coli F41 were detected in any of the calves. The proportion of calves positive for E. coli F17 was greater for DFM calves on d 7 (92% and 96% vs. 81% for BAC, MIX, and CON, respectively), on d 21 (13% and 26% vs. 7% for BAC, MIX, and CON, respectively), and at weaning (48% and 35% vs. 22% for BAC, MIX, and CON, respectively). For Clostridium difficile, more DFM calves were positive on d 7 (65% and 30% vs. 35% for BAC, MIX, and CON, respectively) and 14 (20% and 28% vs. 7% for BAC, MIX, and CON, respectively), but proportion of positive calves was also greater for BAC versus MIX on d 7. More CON calves were positive for Clostridium perfringens on d 14 (14% vs. 3% and 8% for CON, BAC, and MIX, respectively) compared with DFM-fed calves. Incidence of calves positive for C. perfringens was greater in BAC than MIX on d 7 (50% vs. 18%), and greater for MIX than BAC at weaning (9% vs. 0%). For protozoa occurrence, a lower proportion of DFM calves were positive for Cryptosporidium spp. on d 7 (58% and 48% vs. 76% for BAC, MIX, and CON, respectively), but opposite results were observed on d 21 for Cryptosporidium spp. (3% and 11% vs. 0% for BAC, MIX, and CON, respectively) and Eimeria spp. on d 14 (7% and 8% vs. 0% for BAC, MIX, and CON, respectively) and 21 (50% and 59% vs. 38% for BAC, MIX, and CON, respectively). In summary, DFM feeding alleviated the occurrence of pneumonia and improved growth rates, while also modulating the prevalence of bacteria and protozoa in preweaning Gyr × Holstein calves.

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Objective: The objective of this study was to associate the 1016G > A variant of the melanocortin-4 receptor gene with lamb's weight, growth, and meat quality in the Colombian hair sheep breed. Materials and Methods: A total of 168 lambs, weights were measured at birth weight (BW), at weaning adjusted weaning weight (AWW), at 6 months [adjusted weight (AW180)], at slaughter adjusted slaughter weight (ASW), daily weight gain preweaning daily gain (preWDG), and postweaning daily gain (postWDG) weaning, and after slaughter, pH, texture, and cook-loss (CL) in the longissimus thoracis et lumborum (LTL) muscle according to the American Meat Science Association methodology. The 1016G > A genotypes were obtained by sequencing. Genotypic and allele frequencies, heterozygosities, and Hardy-Weinberg equilibrium (HWE) were estimated. Using a generalized linear model, the genotype and the allelic substitution effect were associated with the evaluated traits. Results: The heterozygous genotype (0.48) and G allele (0.61) were the most frequent. Heterozygosities were similar (0.47), indicating HWE. The genotype affected the BW (p < 0.05), with a higher value for the GG genotype (2.69 kg). AWW (12.75 kg), AW180 (19.67 kg), and ASW (31.21 kg) weights and daily weight gain (preWDG = 115.41 gm; postWDG = 96.16 gm) were not associated. Average pH, Warner-Bratzler shear force, and CL were 5.75 units, 49.46 N, and 32.02%, with no genotype effect. The G > A substitution only affected BW at -388 gm (p < 0.05). Conclusion: The 1016G > A variant is polymorphic and affects the BW but not other growth traits or the meat quality of the LTL muscle.

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The rearing of large litters from hyperprolific sows is a characteristic of modern genotypes. However, these sows have body and reproductive characteristics that differentiate them from the genotypes of the past decades, making it necessary to adopt different management strategies. This review describes the main care and challenges associated with the hyperprolificity of sows during the period in which replacement gilts are selected, along with gestation, parturition, lactation, and the weaning-estrus interval. It describes the challenges that these sows' piglets will face during the lactation period and includes some strategies adopted to develop these surplus piglets. In addition, it identifies areas where more research is needed to understand the reproductive management of modern genotypes.

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This study aimed to evaluate the performance and metabolic changes in dairy calves supplemented with lysine and methionine in milk replacer (MR) or starter concentrate (SC). Male Holstein calves (n = 45) were blocked and distributed in Control without supplementation (1) and; Lysine and Methionine supplementation to achieve an intake of 17 and 5.3 g/d in the SC (2) and to achieve of 17 and 5.3 g/d in the MR (3). MR was fed (6 L/d) until the 8th week of life when weaning occurred. Calves were followed until the 10th week of age. Feed intake was measured daily. Weight and body measurements were registered weekly. Blood samples were collected biweekly to evaluate the intermediate metabolism. The AA supplementation resulted in lower body weight at weaning and week 10. Calves fed SC Lys:Met had lower SC intake and lower total feed intake at weaning when compared to control. Calves fed control had higher heart girth, hip-width, and plasma glucose concentration. The supplementation with Lys and Met did not benefit dairy calves' performance nor metabolism in this study. Supplementation through the MR was more efficient than SC to result in adequate daily intakes of AA. Further studies are needed to understand the negative effects of AA on calf starter intake.

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Abstract Background: Heat stress derived from global warming is causing major economic losses in the livestock industry. Objective: To develop a novel methodological approach for determining the influence of climatic factors on the estimation of genetic parameters for growth traits in Retinta cattle breed by using reaction-norm models. Methods: Live weight records (n=7,753) from 3,162 Retinta calves born from 1,249 dams and 85 sires and raised in the Andalusian region (Spain) were analyzed. The effect of heat stress was measured using the temperature-humidity index, calculated with climatological data obtained from four weather stations. A bivariate-random-regression reaction-norm model was used to estimate the (co)variance components of weight until weaning in two different climatic seasons corresponding to warm and cold months. Results: The heritability pattern of individuals reared under diverse environments during the first 90 days of age was different. However, differences were not significant at the end of the growing period. Weaned calves reared during the cold season showed greater growth from 70 to 160 days in comparison with those reared during the warm season. Conclusions: Overall, this assessment did not show significant effects of the genotype-environment interaction. However, highly significant evidence of genotype-climatic condition interaction was found during the calf´s first three months of age.

Resumen Antecedentes: El estrés térmico derivado del calentamiento global está causando pérdidas económicas en la industria ganadera. Objetivo: Desarrollar un enfoque metodológico para estimar la influencia de algunos factores climáticos sobre la estimación de parámetros genéticos en las variables de crecimiento de la raza bovina Retinta. Métodos: Se analizaron registros de peso vivo (n=7.753) de 3.162 terneros hijos de 1.249 vacas y 85 toros, criados en la región de Andalucía (España). El efecto del estrés térmico se midió mediante un índice de temperatura-humedad obtenido a partir de los datos de cuatro estaciones meteorológicas. Se usó un modelo bivariado de regresión aleatoria de "norma-reacción" para estimar la (co)varianza del peso hasta el destete en dos diferentes épocas climáticas correspondientes a los meses cálidos y fríos. Resultados: Se encontraron diferencias en el patrón de heredabilidad de individuos criados en diferentes ambientes durante los primeros 90 días de vida. Sin embargo, tales diferencias no fueron significativas al final del periodo de crecimiento. Los terneros destetados en la época fría mostraron un mayor crecimiento entre 70 y 160 días en comparación con los criados en la temporada cálida. Conclusiones: Se encontró una evidencia altamente significativa de la interacción genotipo-condición climática durante los primeros tres meses de crecimiento del ternero.

Resumo Antecedentes: O estresse térmico devido ao aumento da temperatura média está produzindo grandes perdas econômicas na indústria pecuária. Objetivo: Realizar uma nova abordagem metodológica para estimar a importância dos fatores climáticos em parâmetros genéticos em variáveis de crescimento da população da raça Retinta. Métodos: Foram analisados registros de peso vivo (n=7.753) de 3.162 Retinta bezerros, nascidos de 1.249 vacas e 85 touros criados na região da Andaluzia (Espanha). O efeito do estresse térmico foi medido utilizando o índice de temperatura-umidade obtido com dados climatológicos de quatro estações meteorológicas. Um modelo de regressão aleatória bivariado de norma-reação foi usado para estimar os componentes da (co)variância do peso à desmama em duas estações climáticas com correspondência aos meses quentes e fríos. Resultados: Diferenças foram encontradas no padrão de herdabilidade de indivíduos criados em diferentes ambientes nos primeiros 90 dias de idade. No entanto, essas diferenças não foram significativas no final do período de crescimento. Os bezerros desmamados globalmente na estação fria apresentaram um crescimento maior dos 70 aos 160 dias em comparação com os indivíduos criados na estação quente. Conclusões: Uma evidência altamente significativa da interação genótipo-ambiente foi encontrada durante os primeiros três meses de crescimento do bezerro.

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The ability to positively alter immune and stress response with nutritional compounds is of great interest and importance to the beef industry. There is a proprietary product (OmniGen-AF [OG]; Phibro Animal Health, Quincy, IL) reported to have performance-enhancing benefits by altering animal response to stress and immune challenges. The objective of this 2-yr research project was to study the effect of supplementing OG to beef cows and their calves on breeding and growth performance. One hundred and twelve multiparous beef cows and 48 primiparous cows were randomly assigned to treatment in year 1; control (CON, no OG; n = 56 multiparous and 24 primiparous) or treatment (OG fed at 8.8 g/100 kg body weight [BW]; n = 56 multiparous and 24 primiparous). Multiparous cows (mean ± SD = 6.4 ± 0.4 yr; BW = 589 ± 9.2 kg; body condition score [BCS] 6.2 ± 0.07) were used in both years of the experiment and primiparous cows (mean ± SD = 2.1 ± 0.04 yr of age, weighed 400 ± 7.5 kg, and BSC of 5.6 ± 0.06) were only used in the first year of the experiment. CON and OG supplements were offered over two production cycles beginning in December approximately 60 d prior to projected calving through pre-breeding in May of each year. Calves from treatment cows were offered treatments in a creep supplement limited to a daily rate of 1% as-fed of BW prorated for 3-d/wk feeding from mid-July through weaning with OG offered at 8.8 g/100 kg BW. Primiparous cow's BW, BCS, and calf performance were not affected by treatment (P ≥ 0.15) in year 1. BW of multiparous OG cows tended (P = 0.10) to be heavier at weaning in year 1 and was greater (P = 0.05) at the onset of the experiment in year 2. Body condition of OG cows was greater (P ≤ 0.02) at weaning in both years 1 and 2, as well as at the onset of the experiment in year 2. Calves fed OG from the mature cows gained more (P = 0.05) BW during the creep feeding period than CON. Core body temperatures of OG heifers measured during the late summer with intravaginal temperature data loggers tended (P ≤ 0.10) to be less at 1400 and 1700 hours and were less (P = 0.05) at 1800 hours than CON heifers. Feeding OG did not result in changes (P = 0.25) in serum titer response to the BVD virus of calves during year 2. The results of the current experiment indicate feeding OG to beef cows and calves can result in improvement in BCS of cows, enhance weight gain of calves preweaning, and reduce heat loads in heifer calves during the late summer.

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Our retrospective, cross-sectional study aimed to identify the mortality rate of preweaned heifer calves and associated herd-management factors in family-run dairy holdings in the state of Rio Grande do Sul, Brazil. A survey was made available through an online platform to all the municipalities (n = 494) with a state official extension office (Emater), allowing for any milk producer in RS raising the calves on-farm to take part in the study. A total of 1451 farmers responded to the survey between October 2014 and December 2015. Yearly total mortality, stillbirths and post-natal mortality to weaning were calculated from responses. The association of herd characteristics and practices with herd mortality was evaluated using multilevel multivariable logistic regression models. Herd mortality was modelled as a two vector binded variable that included the number of failures (n = female calves born alive but dead before weaning) and successes (n = weaned female calves) on-farm in the past 12 months. Models included region as random effect. The herds had 13 lactating cows (median, range 1-130). Pure breed herds, especially Holstein, predominated (81 %). Milk production was 190 L/d (median, range 7-4000). Total mortality rate was 8.5 % (1065/12563, median 0.0 %, Q1 - Q3 0.0-14.3 %/farm), and stillbirths 1.7 % (207/12563; median 0.0 %, Q1 - Q3 0.0 - 0 %/farm). Post-natal mortality rate was 6.9 % (858/12356, median 0.0 %, Q1 - Q3 0.0-11.1 %/farm). In 89.2 % of the farms, no stillborn calf was reported, and in only 2.8 % there was more than one case. In 67 % of farms, no death calf born alive was reported; in 33 %, an average of 2 deaths/farm (range 1-12 deaths/farm) was reported. In 16 % of the farms, mortality was ≥ 20 %, and in 4.3 % it was ≥ 50 %. The main reported causes of death were diarrhoea and unknown causes. Higher mortality was associated with herds with mixed breeds (OR = 1.3, CI = 1.09-1.59), performing unattended calvings (OR = 1.2; IC = 1.04-1.40), leaving the calf for long periods with the cow (OR = 1.21, CI = 1.00-1.45), and housing various calves in a pen (OR = 1.4, CI = 1.20-1.60). Furthermore, reduced mortality was associated with medium size herds (i.e. 21-40 lactating cows; OR = 0.82, CI = 0.69-0.97). Although the mortality rate observed is conservatively lower or equal to other international reports, it is higher than could be desired. The factors identified as associated to mortality are understood as proxies for the poor quality of management of the practices adopted. Thus, reduction of mortality is at hand without representing major infrastructural changes.

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The genus Pestivirus, which belongs to the family Flaviviridae, includes ssRNA+ viruses responsible for infectious diseases in swine, cattle, sheep, goats, and other domestic and wild animals. Recently, several putative pestiviruses species have been discovered and characterized in mammalian species (giraffe pestivirus, antelope pestivirus, HoBi virus, Bungowannah virus, and Linda virus); one of these is a genetically distinct pestivirus, named atypical porcine pestivirus (APPV), discovered using the next-generation sequencing technology. APPV has been detected in piglets with congenital tremor (CT) from four different continents, including North America, South America, Europe, and Asia. There is strong evidence that experimental inoculation and in field outbreaks involving APPV induce CT in piglets. Additionally, splay leg (SL) syndrome has been observed concurrently with CT, and it was induced by APPV in experimental studies and some field cases. Animals with a persistent and/or chronic infection condition can shed the virus over time. Viral-RNA is frequently detected in different tissues from CT-piglets; however, high loads of APPV are detected most consistently in central nervous tissue. Moreover, the APPV genome has been recently detected in semen and preputial swabs from boar studs, as well as in serum and tissue samples from wild boars and domestic adult pigs, all known to be clinically healthy. Phylogenetic analysis revealed that the APPV sequence (complete or partial polyprotein) exhibits high genetic diversity between viral strains detected in different countries and formed independent clusters according to geographic location. Additional studies are needed to evaluate the molecular detection and sero-prevalence of APPV around the world. Lastly, more research is needed to understand clinical presentations associated with APPV infection, as well as the economic losses related to the virus in pig production worldwide.

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Environmental enrichment (EE) is an experimental strategy to attenuate the negative effects of different neurological conditions including neonatal hypoxia ischemia encephalopathy (HIE). The aim of the present study was to investigate the influence of prenatal and early postnatal EE in animals submitted to neonatal HIE model at postnatal day (PND) 3. Wistar rats were housed in EE or standard conditions (SC) during pregnancy and lactation periods. Pups of both sexes were assigned to one of four experimental groups, considering the early environmental conditions and the injury: SC-Sham, SC-HIE, EE-sham, and EE-HIE. The offspring were euthanized at two different time points: 48 h after HIE for biochemical analyses or at PND 67 for histological analyses. Behavioral tests were performed at PND 7, 14, 21, and 60. Offspring from EE mothers had better performance in neurodevelopmental and spatial memory tests when compared to the SC groups. HIE animals showed a reduction of IGF-1 and VEGF in the parietal cortex, but no differences in BDNF and TrkB levels were found. EE-HIE animals showed reduction in cell death, lower astrocyte reactivity, and an increase in AKTp levels in the hippocampus and parietal cortex. In addition, the EE was also able to prevent the hippocampus tissue loss. Altogether, present findings point to the protective potential of the prenatal and early postnatal EE in attenuating molecular and histological damage, as well as the neurodevelopmental impairments and the cognitive deficit, caused by HIE insult at PND 3.

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The aim of this study was to evaluate the effects on feed intake, calf performance, feed efficiency, fecal score, passage rate, apparent nutrient digestibility, development of rumen and other organs, and body composition of increasing the total solids content of liquid feed (whole milk) by adding increasing amounts of milk replacer powder during the preweaning period. Crossbred Holstein-Gyr calves (n=32) were assigned to 1 of 4 treatments (n=8 per group), which consisted of different total solids concentrations: 12.5, 15.0, 17.5, and 20.0% of liquid feed. Calves received 6 L of liquid per day, divided into 2 equal meals (0800 and 1600 h) and provided in buckets, from 5 to 55d of age. Starter and water were provided ad libitum during the entire experiment. At 56d of age, animals were killed. Laboratory analysis determined that the actual total solids contents of the liquid feed were 13.5, 16.1, 18.2, and 20.4%, for the proposed 12.5, 15.0, 17.5, and 20.0% total solids treatments, respectively. The osmolality of liquid feed treatments was 265 to 533 mOsm/L. Fecal score was similar among treatments, except for wk 2 and 7. Intake of liquid feed was similar among treatments from 6wk of age. During wk 4, 5, and 6, we detected a linear decrease in starter intake. After wk 7, we observed greater starter intake for calves fed approximately 16.1% total solids. Water intake, feed efficiency, and withers height were similar among treatments. Increasing concentrations of total solids in liquid feed quadratically affected average daily gain, final body weight, and empty body weight. We observed a greater average daily gain for calves fed approximately 20.4% total solids. Passage rate, nutrient digestibility, development of pre-stomachs and intestine, and body composition were similar among treatments. Increasing the concentration of total solids in liquid feed up to 20.4% reduced starter intake between 4 and 6wk of life, but increased average daily gain. It did not affect passage rate, nutrient digestibility, ruminal and organ development, or body composition in calves during the preweaning period, indicating that this strategy may be a viable alternative for feeding without increasing the total volume of liquid feed provided to dairy calves.

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A pecuária de corte brasileira tem sido marcada por intensas transformações, resultantes da aplicação de técnicas modernas de produção, da utilização dos cruzamentos entre raças, e das exigências do mercado consumidor. O desempenho do período pré-desmama é importante por se tratar do primeiro resultado de produtividade animal e a classificação e tipificação das carcaças possibilitam enquadrá-las em diferentes classes e, assim, direcioná-las a diferentes mercados. O objetivo deste trabalho foi comparar o desempenho pré-desmama e características de carcaças entre dois grupos genéticos: Nelore (NE), e ½ sangue Angus-Nelore (F1), os quais foram abatidos sem castração e suplementados a pasto do nascimento ao abate. Foram tomados, ao acaso, 36 animais sendo 18 machos da raça Nelore (NE) e 18 machos oriundos do cruzamento industrial entre Nelore e Angus, machos (F1), sendo todos submetidos ao mesmo manejo e abatidos sem castração, com idade aproximada de 20 meses. Durante o processo de abate, as carcaças foram classificadas e tipificadas. O grupo F1 foi superior ao grupo NE com diferença significativa referente ao peso ao nascer (p=0,0046), peso ajustado aos 205 dias (p=0,0002), peso ao desmame (p=0,0005), ganho de peso diário entre o nascimento e os 205 dias (p=0,001). Quanto às características de carcaças não houve diferença estatística entre os grupos (p>0,05), sendo que, ambos atingiram a exigência frigorífica para espessura de gordura. Observou-se uma superioridade nos animais F1 quanto ao desempenho pré-desmama, e nota-se a possibilidade de terminar animais inteiros a pasto, com acabamento de carcaça mínimo, desde que bem alimentados.

The Brazilian beef cattle industry has been marked by dramatic changes resulting from the application of modern production techniques, use of crossbreeding and consumer market requirements. The performance of the pre-weaning period is important because it is the first result of animal productivity, and the evaluation and classification of carcasses enable their categorization into different classes, and thus, their directing to different markets. The objective of this study was to compare the pre-weaning performance and carcass traits between two genetic groups: Nellore (NE) and Angus-Nellore crossbreed (F1), which were slaughtered without castration, receiving grazing supplementation from birth to slaughter. Thirty-six animals were randomly selected, 18 Nelore (NE) and 18 Angus-Nellore crossbreed (F1) animals, all males, submitted to the same management system and slaughtered without castration, with approximate age of 20 months. During the slaughtering process, carcasses were classified and typified. The F1 group was superior to the NE group with significant differences related to birth weight (p = 0.0046), weight adjusted to 205 days (p = 0.0002), weaning weight (p = 0.0005), daily weight gain between birth and 205 days (p = 0.001). Regarding carcass traits, there was no statistical difference between groups (p> 0.05), and both reached the requirement for fat thickness. F1 animals were superior in relation to pre-weaning performance, and there is possibility to slaughter whole animals on pasture, with minimal carcass finishing if well fed.

La pecuaria de corte brasileña ha sido marcada por intensas transformaciones, resultantes de la aplicación de técnicas modernas de producción, de utilización de los cruzamientos entre razas, y de exigencias del mercado consumidor. El desempeño del período pre destete es importante por tratarse del primer resultado de productividad animal, la clasificación y tipificación de los esqueletos posibilitan encuadrarlos en diferentes clases y, así, dirigirlos a diferentes mercados. El objetivo de esa investigación ha sido comparar el desempeño pre destete y características de esqueletos entre dos grupos genéticos: Nelore (NE), y ½ sangre Angus-Nelore (F1), los cuales fueron abatidos sin castración y suplementados a pasto desde el nacimiento al abate. Fueron tomados, al azar, 36 animales siendo 18 machos de la raza Nelore (NE) y 18 machos oriundos del cruzamiento industrial entre Nelore y Angus, machos (F1), siendo todos sometidos al mismo manejo y abatidos sin castración, con edad aproximada a 20 meses. Durante el proceso de abate, los esqueletos fueron clasificados y tipificados. El grupo F1 fue superior al grupo NE con diferencia significativa referente al peso al nascer (p=0,0046), peso ajustado a los 205 días (p=0,0002), peso al destete (p=0,0005), aumento de peso diario entre el nacimiento y los 205 días (p=0,001). Sobre las características de esqueletos no hubo diferencia estadística entre los grupos (p>0,05), siendo que, ambos alcanzaron la exigencia frigorífica para espesor de grasa. Se observó una superioridad en los animales F1 en el desempeño pre destete, y se nota la posibilidad de terminar animales enteros a pasto, con terminación de esqueleto mínimo, desde que bien alimentados.

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O fornecimento de alimento complementar ao leite da porca durante a lactação (creep feed) é um manejo comumente recomendado para produtores. A prática foi introduzida como estratégia para minimizar os efeitos deletérios do desmame abrupto e precoce, bem como para uniformizar as leitegadas a serem desmamadas, aumentar o peso ao desmame e acelerar a adaptação do trato gastrintestinal dos leitões a dietas sólidas. As dietas creep feed são formuladas buscando-se altos níveis de digestibilidade e palatabilidade e incluem ingredientes de alta qualidade e alto custo. No entanto, resultados de pesquisas que indiquem que a simples oferta de creep feed é eficiente para minimizar os efeitos deletérios do desmame ou para facilitar a adaptação dos leitões a dietas iniciais ainda são escassos e pouco consolidados. O objetivo desse trabalho foi revisar os fatores que influenciam o consumo de creep feed, os efeitos do consumo dessas dietas sobre o desempenho durante a lactação, bem como as possíveis influências sobre o desenvolvimento enzimático, a ocorrência de diarreias e o desempenho pós-desmame de leitões desmamados entre 21 e 28 dias de idade. Os resultados encontrados indicam que leitões lactentes não apresentam maturidade intestinal suficiente para que estas dietas sejam voluntariamente consumidas e adequadamente digeridas. Mesmo os animais dispostos ao consumo não o fazem em quantidade suficiente para promover a adaptação enzimática ou melhorar o desempenho pós-desmame. Ao contrário do esperado, o consumo de creep feed, especialmente se em baixas quantidades, pode estar associado a sensibilização do trato gastrintestinal, que resulta em reações de hipersensibilidade e diarreia pós-desmame. Concluiu-se que a simples oferta de creep feed não é eficiente para promoção do crescimento na lactação e no pós-desmame, ou para facilitar a adaptação de leitões desmamados precocemente a dietas sólidas. Portanto, destaca-se a necessidade de pesquisas na área, visando...

Providing a solid diet in addition to sow milk during lactation (creep feed) is a management commonly recommended to producers. This practice was introduced as a strategy to minimize the deleterious effects of abrupt and early weaning, as well as to standardize the litters to be weaned, to increase weaning weight, and to accelerate the adaptation of the gastrointestinal tract of piglets to solid diets. Creep feeds are formulated to present high levels of digestibility and palatability and to contain high-quality and high-cost ingredients. However, the results of studies indicating that the simple offer of creep feed is efficient in minimizing the deleterious effects of weaning or in facilitating the adaptation of piglets to early diets are still sparse and poorly consolidated. The objective of this study was to review factors that influence the consumption of creep feed and the effects of consumption of these diets on performance during lactation, as well as possible effects on enzyme production, occurrence of diarrhea episodes and postweaning performance of piglets weaned at 21 to 28 days of age. The results indicate that the intestinal maturity of suckling piglets is not sufficient to permit voluntary consumption and adequate digestion of the diets. Even animals ready for consumption did not ingest sufficient amounts to promote enzymatic adaptation or to improve postweaning performance. Contrary to expectations, the consumption of creep feed, especially in low amounts, may be associated with sensitization of the gastrointestinal tract which results in hypersensitivity reactions and postweaning diarrhea. It can be concluded that the simple offer of creep feed is not efficient in promoting growth during lactation and postweaning, nor does it facilitate the early adaptation of weaned piglets to solid diets. Studies in this area are therefore necessary to develop techniques that can effectively minimize losses resulting from the practice of early weaning...

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O fornecimento de alimento complementar ao leite da porca durante a lactação (creep feed) é um manejo comumente recomendado para produtores. A prática foi introduzida como estratégia para minimizar os efeitos deletérios do desmame abrupto e precoce, bem como para uniformizar as leitegadas a serem desmamadas, aumentar o peso ao desmame e acelerar a adaptação do trato gastrintestinal dos leitões a dietas sólidas. As dietas creep feed são formuladas buscando-se altos níveis de digestibilidade e palatabilidade e incluem ingredientes de alta qualidade e alto custo. No entanto, resultados de pesquisas que indiquem que a simples oferta de creep feed é eficiente para minimizar os efeitos deletérios do desmame ou para facilitar a adaptação dos leitões a dietas iniciais ainda são escassos e pouco consolidados. O objetivo desse trabalho foi revisar os fatores que influenciam o consumo de creep feed, os efeitos do consumo dessas dietas sobre o desempenho durante a lactação, bem como as possíveis influências sobre o desenvolvimento enzimático, a ocorrência de diarreias e o desempenho pós-desmame de leitões desmamados entre 21 e 28 dias de idade. Os resultados encontrados indicam que leitões lactentes não apresentam maturidade intestinal suficiente para que estas dietas sejam voluntariamente consumidas e adequadamente digeridas. Mesmo os animais dispostos ao consumo não o fazem em quantidade suficiente para promover a adaptação enzimática ou melhorar o desempenho pós-desmame. Ao contrário do esperado, o consumo de creep feed, especialmente se em baixas quantidades, pode estar associado a sensibilização do trato gastrintestinal, que resulta em reações de hipersensibilidade e diarreia pós-desmame. Concluiu-se que a simples oferta de creep feed não é eficiente para promoção do crescimento na lactação e no pós-desmame, ou para facilitar a adaptação de leitões desmamados precocemente a dietas sólidas. Portanto, destaca-se a necessidade de pesquisas na área, visando...(AU)

Providing a solid diet in addition to sow milk during lactation (creep feed) is a management commonly recommended to producers. This practice was introduced as a strategy to minimize the deleterious effects of abrupt and early weaning, as well as to standardize the litters to be weaned, to increase weaning weight, and to accelerate the adaptation of the gastrointestinal tract of piglets to solid diets. Creep feeds are formulated to present high levels of digestibility and palatability and to contain high-quality and high-cost ingredients. However, the results of studies indicating that the simple offer of creep feed is efficient in minimizing the deleterious effects of weaning or in facilitating the adaptation of piglets to early diets are still sparse and poorly consolidated. The objective of this study was to review factors that influence the consumption of creep feed and the effects of consumption of these diets on performance during lactation, as well as possible effects on enzyme production, occurrence of diarrhea episodes and postweaning performance of piglets weaned at 21 to 28 days of age. The results indicate that the intestinal maturity of suckling piglets is not sufficient to permit voluntary consumption and adequate digestion of the diets. Even animals ready for consumption did not ingest sufficient amounts to promote enzymatic adaptation or to improve postweaning performance. Contrary to expectations, the consumption of creep feed, especially in low amounts, may be associated with sensitization of the gastrointestinal tract which results in hypersensitivity reactions and postweaning diarrhea. It can be concluded that the simple offer of creep feed is not efficient in promoting growth during lactation and postweaning, nor does it facilitate the early adaptation of weaned piglets to solid diets. Studies in this area are therefore necessary to develop techniques that can effectively minimize losses resulting from the practice of early weaning...(AU)

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A pecuária de corte brasileira tem sido marcada por intensas transformações, resultantes da aplicação de técnicas modernas de produção, da utilização dos cruzamentos entre raças, e das exigências do mercado consumidor. O desempenho do período pré-desmama é importante por se tratar do primeiro resultado de produtividade animal e a classificação e tipificação das carcaças possibilitam enquadrá-las em diferentes classes e, assim, direcioná-las a diferentes mercados. O objetivo deste trabalho foi comparar o desempenho pré-desmama e características de carcaças entre dois grupos genéticos: Nelore (NE), e ½ sangue Angus-Nelore (F1), os quais foram abatidos sem castração e suplementados a pasto do nascimento ao abate. Foram tomados, ao acaso, 36 animais sendo 18 machos da raça Nelore (NE) e 18 machos oriundos do cruzamento industrial entre Nelore e Angus, machos (F1), sendo todos submetidos ao mesmo manejo e abatidos sem castração, com idade aproximada de 20 meses. Durante o processo de abate, as carcaças foram classificadas e tipificadas. O grupo F1 foi superior ao grupo NE com diferença significativa referente ao peso ao nascer (p=0,0046), peso ajustado aos 205 dias (p=0,0002), peso ao desmame (p=0,0005), ganho de peso diário entre o nascimento e os 205 dias (p=0,001). Quanto às características de carcaças não houve diferença estatística entre os grupos (p>0,05), sendo que, ambos atingiram a exigência frigorífica para espessura de gordura. Observou-se uma superioridade nos animais F1 quanto ao desempenho pré-desmama, e nota-se a possibilidade de terminar animais inteiros a pasto, com acabamento de carcaça mínimo, desde que bem alimentados.(AU)

The Brazilian beef cattle industry has been marked by dramatic changes resulting from the application of modern production techniques, use of crossbreeding and consumer market requirements. The performance of the pre-weaning period is important because it is the first result of animal productivity, and the evaluation and classification of carcasses enable their categorization into different classes, and thus, their directing to different markets. The objective of this study was to compare the pre-weaning performance and carcass traits between two genetic groups: Nellore (NE) and Angus-Nellore crossbreed (F1), which were slaughtered without castration, receiving grazing supplementation from birth to slaughter. Thirty-six animals were randomly selected, 18 Nelore (NE) and 18 Angus-Nellore crossbreed (F1) animals, all males, submitted to the same management system and slaughtered without castration, with approximate age of 20 months. During the slaughtering process, carcasses were classified and typified. The F1 group was superior to the NE group with significant differences related to birth weight (p = 0.0046), weight adjusted to 205 days (p = 0.0002), weaning weight (p = 0.0005), daily weight gain between birth and 205 days (p = 0.001). Regarding carcass traits, there was no statistical difference between groups (p> 0.05), and both reached the requirement for fat thickness. F1 animals were superior in relation to pre-weaning performance, and there is possibility to slaughter whole animals on pasture, with minimal carcass finishing if well fed.(AU)

La pecuaria de corte brasileña ha sido marcada por intensas transformaciones, resultantes de la aplicación de técnicas modernas de producción, de utilización de los cruzamientos entre razas, y de exigencias del mercado consumidor. El desempeño del período pre destete es importante por tratarse del primer resultado de productividad animal, la clasificación y tipificación de los esqueletos posibilitan encuadrarlos en diferentes clases y, así, dirigirlos a diferentes mercados. El objetivo de esa investigación ha sido comparar el desempeño pre destete y características de esqueletos entre dos grupos genéticos: Nelore (NE), y ½ sangre Angus-Nelore (F1), los cuales fueron abatidos sin castración y suplementados a pasto desde el nacimiento al abate. Fueron tomados, al azar, 36 animales siendo 18 machos de la raza Nelore (NE) y 18 machos oriundos del cruzamiento industrial entre Nelore y Angus, machos (F1), siendo todos sometidos al mismo manejo y abatidos sin castración, con edad aproximada a 20 meses. Durante el proceso de abate, los esqueletos fueron clasificados y tipificados. El grupo F1 fue superior al grupo NE con diferencia significativa referente al peso al nascer (p=0,0046), peso ajustado a los 205 días (p=0,0002), peso al destete (p=0,0005), aumento de peso diario entre el nacimiento y los 205 días (p=0,001). Sobre las características de esqueletos no hubo diferencia estadística entre los grupos (p>0,05), siendo que, ambos alcanzaron la exigencia frigorífica para espesor de grasa. Se observó una superioridad en los animales F1 en el desempeño pre destete, y se nota la posibilidad de terminar animales enteros a pasto, con terminación de esqueleto mínimo, desde que bien alimentados.(AU)

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Foram estimados (co)variâncias, coeficientes de herdabilidade e tendências genéticas, bem como preditas mudanças genéticas para peso aos 120 (P120), 210 (P210), 365(P365), 450 (P450) e 550 (P550) dias de idade em animais da raça Nelore criados na região do Trópico Úmido do Brasil. Foram utilizados 65.876 registros de animais nascidos entre os anos de 1993 a 2010, criados a pasto. Os componentes de (co)variância foram estimados pelo método da máxima verossimilhança restrita e os valores genéticos foram preditos por modelos mistos sob modelo animal. As tendências genéticas foram estimadas pela regressão dos valores genéticos sobre o ano de nascimento dos animais. Os coeficientes de herdabilidade do efeito direto estimados foram de 0,37±0,019; 0,39±0,019; 0,41±0,013; 0,41±0,015 e0,41±0,021 para P120, P210, P365, P450 e P550, respectivamente. As estimativas de herdabilidades maternais para P120 e P210 foram 0,05±0,011 e 0,06±0,011, respectivamente. Os ganhos genéticos diretos médios foram 1,326, 2,014, 2,670,3,056 e 3,128 kg/ano para P120, P210, P365, P450 e P550, respectivamente. As estimativas dos parâmetros e tendência genética indicam a existência de progresso genético para pesos pré e pós-desmame, nos rebanhos da região do Trópico Úmido do Brasil.(AU)

(Co)variances, heritability and genetics change were estimated for weight at 120 (W120),  210 (W210), 365 (W365), 450 (W450) and 550 (W550 ) days of age in Nellore cattle from the Humid Tropical region of Brazil. A total of 65,876 records of animals born between 1993 to 2010 and raised on pasture were used. The (co)variance components were estimated by restricted maximum likelihood, and breeding values were predicted using an individual animal model. The genetic trends were plotted by linear regression of breeding values in the animals' birth year. The heritability coefficients due to direct genetic effect were 0.37±0.019; 0.39±0.019; 0.41±0.013; 0.41±0.015 and 0.41±0.021 The maternal heritability estimates for W120 and W210 were 0.05±0.011 and 0.06±0.011, respectively. The genetic gains were 1.326, 2.014, 2.670, 3.056 and 3.128 kg/year for W120, W210, W365, W450 and W550, respectively. The estimates of genetic parameters and trends indicate the existence of genetic progress in pre- and post-weight traits from herds of Brazil Tropic Humid region.(AU)

Assuntos

RESUMO

Foram estimados (co)variâncias, coeficientes de herdabilidade e tendências genéticas, bem como preditas mudanças genéticas para peso aos 120 (P120), 210 (P210), 365(P365), 450 (P450) e 550 (P550) dias de idade em animais da raça Nelore criados na região do Trópico Úmido do Brasil. Foram utilizados 65.876 registros de animais nascidos entre os anos de 1993 a 2010, criados a pasto. Os componentes de (co)variância foram estimados pelo método da máxima verossimilhança restrita e os valores genéticos foram preditos por modelos mistos sob modelo animal. As tendências genéticas foram estimadas pela regressão dos valores genéticos sobre o ano de nascimento dos animais. Os coeficientes de herdabilidade do efeito direto estimados foram de 0,37±0,019; 0,39±0,019; 0,41±0,013; 0,41±0,015 e0,41±0,021 para P120, P210, P365, P450 e P550, respectivamente. As estimativas de herdabilidades maternais para P120 e P210 foram 0,05±0,011 e 0,06±0,011, respectivamente. Os ganhos genéticos diretos médios foram 1,326, 2,014, 2,670,3,056 e 3,128 kg/ano para P120, P210, P365, P450 e P550, respectivamente. As estimativas dos parâmetros e tendência genética indicam a existência de progresso genético para pesos pré e pós-desmame, nos rebanhos da região do Trópico Úmido do Brasil.

(Co)variances, heritability and genetics change were estimated for weight at 120 (W120),  210 (W210), 365 (W365), 450 (W450) and 550 (W550 ) days of age in Nellore cattle from the Humid Tropical region of Brazil. A total of 65,876 records of animals born between 1993 to 2010 and raised on pasture were used. The (co)variance components were estimated by restricted maximum likelihood, and breeding values were predicted using an individual animal model. The genetic trends were plotted by linear regression of breeding values in the animals' birth year. The heritability coefficients due to direct genetic effect were 0.37±0.019; 0.39±0.019; 0.41±0.013; 0.41±0.015 and 0.41±0.021 The maternal heritability estimates for W120 and W210 were 0.05±0.011 and 0.06±0.011, respectively. The genetic gains were 1.326, 2.014, 2.670, 3.056 and 3.128 kg/year for W120, W210, W365, W450 and W550, respectively. The estimates of genetic parameters and trends indicate the existence of genetic progress in pre- and post-weight traits from herds of Brazil Tropic Humid region.

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RESUMO

The objective of this research was to estimate the relative magnitude of effects included in contemporary groups (CG) and their interactions with adjusted and actual 120 d and 210 d weights in 72,731 male and female Nelore calves born from 1985 to 2005 in 40 herds from PMGRN (Genetic Improvement Program of Nelore). Ten models with different CG structures were compared. The analyses were done using the general linear models (GLM) procedure run in SAS software. All of the effects included in the CG for each model were significant (p < 0.001) for the four traits analyzed. Inclusion of semester or trimester of birth as part of a CG was more appropriate than its use as an independent effect in the model because it accounted for interactions with the other effects in the CG. Calf sex (CS) and dam age at calving (DAC) had similar effects across the models, which suggested independence from other effects in these models. The corresponding age deviation effect had a larger impact on actual weight at 120 d than any other effect in all of the models tested. The use of actual weights in models with no CS effect in CG provides an alternative that would allow better genetic connectedness among CGs and greater accuracy in genetic evaluations.

RESUMO

The objective of this research was to estimate the relative magnitude of effects included in contemporary groups (CG) and their interactions with adjusted and actual 120 d and 210 d weights in 72, 731 male and female Nelore calves born from 1985 to 2005 in 40 herds from PMGRN (Genetic Improvement Program of Nelore). Ten models with different CG structures were compared. The analyses were done using the general linear models (GLM) procedure run in SAS software. All of the effects included in the CG for each model were significant (p < 0.001) for the four traits analyzed. Inclusion of semester or trimester of birth as part of a CG was more appropriate than its use as an independent effect in the model because it accounted for interactions with the other effects in the CG. Calf sex (CS) and dam age at calving (DAC) had similar effects across the models, which suggested independence from other effects in these models. The corresponding age deviation effect had a larger impact on actual weight at 120 d than any other effect in all of the models tested. The use of actual weights in models with no CS effect in CG provides an alternative that would allow better genetic connectedness among CGs and greater accuracy in genetic evaluations.

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RESUMO

O objetivo deste trabalho foi avaliar e classificar as principais causas de morte de leitões com até seis dias de idade, em umsistema intensivo de suínos confinados (SISCO), localizado na região médio-norte do estado de Mato Grosso durante o anode 2006. Observaram-se 48.416 leitões provenientes de 2.054 matrizes. Verificou-se taxa de mortalidade de 7,43% do totalde nascidos vivos. As causas mais frequentes de mortalidade, em relação ao total de nascidos vivos, foram esmagamento(24,14%), debilitação (8,01%), síndrome diarreica (6,0%), defeitos genéticos (2,41%) e outras causas sem diagnósticoconfirmado durante a necrópsia (15,20%). A taxa de natimortalidade em relação ao total de nascidos foi de 5,59%. Comrelação à sazonalidade das mortes, observou-se maior índice de mortalidade por síndrome diarreica durante a primavera,que coincide com os meses mais quentes do ano, não observando tendência para morte por esmagamento em nenhumaépoca do ano.

The objective of this research was to evaluate and to classify (by means of postmortem findings), the occurrence of the preweaning losses of piglets until the six days of age, in a intensive system of bordered pigs, at the middle north of Mato Grosso State during the year 2006. They had been observed a total of 48.416 piglets proceeding from 2.054 wombs. Was verified the tax of mortality of 7,43% of that livings piglets had been born. The most frequent causes of losses were overlaying (24.14 %), diverse causes (15.20), weakness (8.01 %), diarrhea syndrome (6.0 %) and genetic defects (2.41 %). Stillbirth rate, in relation to total born, was 5.59 %. In relation of periodicity deaths, it was observed a higher number of diarrhea syndrome during the spring, that coincides with the hottest months of the year, wasn’t observed trends of overlaying deaths none time during the year.

Assuntos

RESUMO

O objetivo deste trabalho foi avaliar e classificar as principais causas de morte de leitões com até seis dias de idade, em umsistema intensivo de suínos confinados (SISCO), localizado na região médio-norte do estado de Mato Grosso durante o anode 2006. Observaram-se 48.416 leitões provenientes de 2.054 matrizes. Verificou-se taxa de mortalidade de 7,43% do totalde nascidos vivos. As causas mais frequentes de mortalidade, em relação ao total de nascidos vivos, foram esmagamento(24,14%), debilitação (8,01%), síndrome diarreica (6,0%), defeitos genéticos (2,41%) e outras causas sem diagnósticoconfirmado durante a necrópsia (15,20%). A taxa de natimortalidade em relação ao total de nascidos foi de 5,59%. Comrelação à sazonalidade das mortes, observou-se maior índice de mortalidade por síndrome diarreica durante a primavera,que coincide com os meses mais quentes do ano, não observando tendência para morte por esmagamento em nenhumaépoca do ano.

The objective of this research was to evaluate and to classify (by means of postmortem findings), the occurrence of the preweaning losses of piglets until the six days of age, in a intensive system of bordered pigs, at the middle north of Mato Grosso State during the year 2006. They had been observed a total of 48.416 piglets proceeding from 2.054 wombs. Was verified the tax of mortality of 7,43% of that livings piglets had been born. The most frequent causes of losses were overlaying (24.14 %), diverse causes (15.20), weakness (8.01 %), diarrhea syndrome (6.0 %) and genetic defects (2.41 %). Stillbirth rate, in relation to total born, was 5.59 %. In relation of periodicity deaths, it was observed a higher number of diarrhea syndrome during the spring, that coincides with the hottest months of the year, wasnt observed trends of overlaying deaths none time during the year.(AU)

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