Influence of weaning management at 30, 75 and 180 days of age on non-esterified fatty acids and reproductive performance in beef cows.

This study aimed to investigate the effect of age at weaning of calves on non-esterified fatty acids (NEFA) and reproductive parameters of beef cows. Animals (n = 65) were randomly assigned to three treatments after calving: hyper-early weaning (W30) at 32 ± 0.89 days, early weaning (W75) at 77 ± 0.95 days, and conventional weaning (W180) at 183 ± 0.82 days. Body weight (BW) and body condition score (BCS) were evaluated at parturition (AP) and at 30, 45, 64, 81, 100 and 115 days postpartum (dPP). Blood samples were collected to analyze NEFA levels and progesterone (P4) at 30, 45, 64 and 81 dPP. Higher BW and BCS were observed from 64 to 115 dPP in W30 cows than W180 ones (p < 0.05). Cows subjected to W30 condition had higher levels of NEFA at 30 dPP compared to 64 and 81 dPP (p < 0.05). We also observed that cows from W180 group showed decreased levels of NEFA at 30 dPP compared to 45 (p < 0.01) and 64 dPP (p < 0.05). The highest P4 level was observed at 64 dPP in W30 cows compared to W75 and W180 (p < 0.05). We also observed higher CR of W30 (86%) compared to W180 (47%) at 45 dPP (p < 0.05). The overall pregnancy rate (PR) was higher for W30 (95.5%) than W180 (73.9%). In addition, higher BW at calving and P4 levels at 30 dPP were positively correlated with the possibility of pregnancy (p < 0.05). Improvement in BW and BCS were observed in cows subjected to hyper-early weaning management. However, levels of NEFA decreased as the postpartum period progressed. We concluded that cows who weaned calves hyper-early have greater chances of increasing cyclicity and PRs.

The influence of weaning age and biocholine supplementation to post-weaning growth and puberty in Brangus heifers.

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.

Fetal programming in sheep: Effects on pre- and postnatal organs and glands development in lambs.

The present systematic review and meta-analysis aim to summarize the effects of maternal undernutrition or overnutrition during pregnancy on the absolute weight and relative weight of the organs (liver, kidneys, heart, spleen, and lung) and glands (adrenal, pancreas, and thyroid) measured during gestation, birth and the postnatal period in lambs. After completing the search, selection, and data extraction steps, the measure of effect was generated by the individual comparison of each variable response compared with the average of the control and treated group (undernutrition or overnutrition) using the DerSimonian and Laird method for random effects. The liver was the organ most affected by maternal undernutrition, as the absolute weight of the liver was reduced during pregnancy, birth, and the postnatal period. The extent of this effect is related to the duration of the intervention. Reductions in the absolute fetal weight of the lungs and spleen have also been observed. No change in organs weight were observed when the results were expressed as relative weight. For overnutrition, the fetal weight of the liver was reduced to both absolute and relative values. In contrast, the relative weight of the kidneys has been increased. For the glands analyzed, no changes in weight were observed in either scenario (absolute or relative weight). Thus, the organs are more likely to suffer weight changes, especially during pregnancy, as a result of maternal nutrition. However, this change in organ weight seems to be closely related to the reduction in body weight of the progeny as a whole.

Perception of beef quality for Spanish and Brazilian consumers.

Understanding the priorities of beef consumers is important for planning strategies to attract and maintain each customer. Using self-administered interviews with Spanish and Brazilian adults who regularly consume beef, we analyzed their purchasing behaviors in relation to their perceptions and priorities regarding beef quality that guide their choices. The current study identifies the influences of information (labeling and marketing) requirements, concerns about humane production systems, and the intrinsic characteristics of beef. To evaluate the data extracted from the interviews, the questions were grouped into four main factors. While extrinsic factors are the highest valued in both Spain and Brazil, those such as beef freshness and tenderness present inverse concerns between the two countries based on cultural dissimilarities. The data also reveals a clear symmetry among consumers who increasingly seek specific pre-purchase information and products with guaranteed superior quality. Despite other characteristics that differentiate developed and developing countries, the perceptions of quality among consumers in Spain and Brazil are decidedly similar.

Pregnant beef cow's nutrition and its effects on postnatal weight and carcass quality of their progeny.

A systematic review (SR) and meta-analysis (MA) were performed to evaluate the effects of different energy levels (metabolizable energy, ME) and crude protein (CP), supplied to pregnant cows, on weight of their progenies at 60 (BW60), 100 (BW100), 180 (BW180) and 205 (BW205) days of age, average daily gain (ADG), and weight, age, loin eye area (LEA), marbling and fat thickness (FT) at slaughter. The SR was performed on two electronic databases. The MA for random effects was performed for each response variable separately. The BW60 was reduced (P<0.001; I2 = 78.9%) when cows consumed CP and ME above the required levels during the third trimester of pregnancy (3TRI). The BW205 was lower (P<0.001; I2 = 92.6%) when cows consumed ME above the recommended levels in the second trimester of pregnancy (2TRI) and 3TRI. Conversely, the ADG was higher when cows consumed CP (P = 0.032; I2 = 96.1%) and ME (P<0.001; I2 = 96.1%) above the required levels. The steers whose mothers consumed CP and ME above the required levels during the 3TRI were slaughtered 5.5 days earlier (P = 0.015; I2 = 98.5%) compared to other steers. The marbling was higher (P<0.001; I2 = 91.7%) in calves born to mothers consuming CP and ME above the recommended levels, regardless of the gestation phase. The FT was higher (P<0.001; I2 = 0%) in the offspring of cows that consumed CP and ME above the required levels during the 3TRI. Thus, CP and ME intake, at levels higher than those recommended by the NRC, by pregnant cows in the 3TRI reduces the progeny weight up to 205 days of age. However, this is advantageous during the finishing phase, as it reduces slaughter age and increases the ADG and carcass quality by improving marbling and FT.

Efficiency in Cow-Calf Systems With Different Ages of Cow Culling.

The bioeconomic efficiency of cow-calf systems was compared by a deterministic dynamic simulation. The simulation model considered stable cow-calf systems differentiated by the maximum age for culling cows, lifetime, culled at 4-13 years old. The necessary supply of metabolizable energy for the herd was established as natural grasslands, cultivated pasture in the winter/spring, and pre-dried pasture produced by the system. The biological efficiency of the systems was considered the ratio between the production of total live weight and the metabolizable energy consumed over one production cycle. Economic efficiency was determined by the ratio between gross margin and production area and the ratio between gross margin and number of cows. Bioeconomic efficiency was determined by a simple linear regression between biological efficiency, economic efficiency per area, and economic efficiency per cow. The efficiency of the animal unit, considering biological efficiency and economic efficiency per area were better in the system that culled cows at 4 years old, while economic efficiency per cow was better in the system that culled cows at 13 years old. In determining the bioeconomic efficiency of the systems, the best results were found in the system that culled cows at 6 years old, which suggests that the best efficiency of a cow-calf herd is reached when the adult age and mature weight of the cow are reached, and there is no more energy used for growing. The results indicate that stable cow-calf herds express their best biological efficiency and economic efficiency per area when the cow culling age is lower. However, economic efficiency per cow depends on cows that remain in the herd as long as possible. The culling age of cow that balances these biological and economic indicators is reached around 5 and half years.

Effect of scrotal insulation on sperm quality and seminal plasma proteome of Brangus bulls.

Seminal plasma (SP) contributes to sperm physiology and metabolism, prevents premature capacitation, and protects sperm against oxidative stress. In order to evaluate the impact of heat stress in the semen of tropically adapted Brangus breed and in their seminal plasma proteome, we studied the effects of scrotal insulation for 72 h. Semen samples from six bulls, between 7 and 8 years of age, were collected prior to scrotal insulation (pre-insulation), and at 4 and 11 wk after insulation. Seminal plasma samples were analyzed by 2D SDS-PAGE and liquid chromatography coupled with mass spectrometry (LC-MS/MS). Insulation caused decrease in vigour, gross and total motility after 4 wk of scrotal insult (P < 0.001). Total defects in sperm were higher after 4 wk compared to pre-insulation and 11 wk after scrotal insulation (P < 0.001). The analysis of the 2D protein profile of the SP resulted in the identification 183 unique protein spots in all gels evaluated. There was no difference in mean number of protein spots amongst time points. Eight protein spots were more abundant in SP after scrotal insulation, returning to the same expression level at 11 wk post-insulation. One spot had higher abundance at 11 wk post-insulation, and one spot had decreased abundance 4 wk after insulation. The ten protein spots with differential abundance amongst time points were identified as Seminal plasma protein PDC-109, Seminal plasma protein A3, Seminal plasma protein BSP-30 kDa, Spermadhesin-1 and Metalloproteinase inhibitor 2. The validation of these five proteins as biomarkers for thermal testicular stress in Brangus breed would allow the development of new biotechnologies that could improve bovine semen analysis in breeding systems in tropical and subtropical conditions. A close association between the identified BSP and Spermadhesin-1 was evidenced in protein-protein interaction analysis. Based on gene ontology analysis, variation in sperm function after insulation could be explained by variation in the expressed proteins in the SP. Further studies are required to verify if these proteins could be used as biomarkers for the identification of bulls with increased seminal resistance to heat stress in Brangus breed.

Typology of beef production systems according to bioeconomic efficiency in the south of Brazil / Tipologia de sistemas de produção de carne bovina de acordo com a eficiência bioeconômica no sul do Brasil

ABSTRACT: The objective of this study was to evaluate the bioeconomic efficiency of beef cattle production systems in the south of Brazil. A survey was conducted with 33 beef cattle farmers operating with complete cycle production systems in areas larger or equal to 900 ha. Answers were classified in two drivers, technology (TEC) and management (MAN), which were separated into subfactors with their respective components. Multiple correspondence analysis, Tukey test, cluster analysis, and Pearson correlation were the statistics procedures. The TEC components were above normal for Brazilian farmers, but the gross margin is still lower than that needed to generate financial resources for a proper remuneration of cattle farmer. Farmers were classified into three clusters according to bioeconomic efficiency: low (LEL), intermediate (IEL), or high-efficiency level (HEL). The TEC driver differentiated the LEL x HEL clusters and the MAN, mainly expressed in costs, the IEL x HEL. Positive correlation between age at first mating and age at slaughter in the HEL cluster explains the higher costs when compared to IEL because of the use of differentiated feed resources. Investments in technologies related to herd feeding in HEL cluster improved the productivity by only 20% and the cost per hectare by 95 USD ha-1 in comparison to IEL cluster. The main differences between farmers are because of the use of technologies related to feeding and cost management. Therefore, before implementing a new technology, an economic evaluation is necessary.

RESUMO: O objetivo deste estudo foi avaliar a eficiência bioeconômica em sistemas de produção de bovinos de corte no sul do Brasil. A pesquisa foi realizada com 33 pecuaristas que operam com sistemas de produção baseado em ciclo completo, em áreas maiores ou iguais a 900 hectares. As respostas foram classificadas em dois fatores: tecnologia (TEC) e gestão (GES), os quais foram separados em subfatores com seus respectivos componentes. A análise de correspondência múltipla, teste de Tukey, análise de cluster e correlação de Pearson foram os procedimentos estatísticos. Os componentes do TEC estavam acima do normal para os pecuaristas brasileiros, mas a margem bruta ainda é menor do que a necessária para gerar recursos financeiros para uma remuneração adequada ao pecuarista. Os pecuaristas foram classificados em três grupos de acordo com a eficiência bioeconômica: baixo (BNE), intermediário (INE) ou alto nível de eficiência (ANE). O driver TEC diferenciou os clusters BNE x ANE e o GES, expresso principalmente em custos, o INE x ANE. A correlação positiva entre a idade no primeiro acasalamento e a idade ao abate no agrupamento ANE explica os custos mais elevados quando comparados aos INE, devido ao uso de recursos alimentares diferenciados. Os investimentos em tecnologias relacionadas à alimentação de rebanho no agrupamento ANE melhoraram a produtividade em apenas 20% e o custo por hectare em 95 USD ha-1 em comparação ao cluster INE. As principais diferenças entre os pecuaristas se devem ao uso de tecnologias relacionadas à alimentação e ao gerenciamento de custos. Portanto, antes de implementar uma nova tecnologia, uma avaliação econômica é necessária.

How do Brazilian citizens perceive animal welfare conditions in poultry, beef, and dairy supply chains?

The aim of this study was to understand the perceptions of Brazilian citizens about the general conditions of animal welfare in the poultry, beef, and dairy supply chains. To reach this aim, an online survey was conducted. The analysis was based on descriptive statistics and three logistic regression models. Results of descriptive statistics showed that citizens in Brazil had mostly negative perceptions about the conditions of animal welfare in the poultry, beef, and dairy supply chains. Results of the logistic regression models showed that citizens with a background in agricultural/veterinary sciences, and citizens who reported a higher level of knowledge about poultry and dairy supply chains were more likely to perceive the general conditions of animal welfare in these two supply chains as being bad. Citizens who reported previous contact with poultry farms were also more likely to perceive the general conditions of animal welfare in the poultry supply chain as being bad. In addition, the perception that farmers are mainly focused on the economic aspect of farming and less on animal welfare, the perception that animals do not have a good quality of life while housed on farms, and the perception that animals are not adequately transported and slaughtered, negatively impact on perceptions about the general conditions of animal welfare in the poultry, beef, and dairy supply chains.

Effect of breed on testicular blood flow dynamics in bulls.

The evaluation of testicular hemodynamics can contribute significantly to the understanding of the thermoregulatory mechanisms and oxygen supply of the testis in domestic animals. The present study aimed to characterize circulatory dynamics using the mean velocity (MV), pulsatility index (PI) and resistive index (RI) of the supratesticular artery in bulls. We evaluated 334 bulls of five different breeds (Nelore, Hereford, Aberdeen Angus, Braford and Brangus) by performing a velocimetry analysis using Doppler ultrasonography. Data were compared by Welch's ANOVA, Games-Howell (post-hoc test) and Spearman correlation with a significance level of 5%. The overall MV of 12.14 ±â€¯0.30 cm/s differed among breeds. In addition, we observed that Brangus bulls showed higher (P < 0.05) MV (16.28 ±â€¯1.02 cm/s) compared to Nelore bulls (8.76 ±â€¯0.40 cm/s). The RI had an overall mean of 0.41 ±â€¯0.01 and differed among breeds. We observed higher (P < 0.05) RI values in Hereford (0.44 ±â€¯0.01) compared to Brangus (0.36 ±â€¯0.02) animals. Overall, the PI values (0.33 ±â€¯0.01) did not differ (P > 0.05) among breeds. The correlation between the PI and RI (0.936; P < 0.001) was high and positive; however, the correlations were low and negative between MV and the PI (-0.228; P < 0.001) and between MV and the RI (-0.270; P < 0.001). We concluded that there are differences in the MV and RI of the bulls' supratesticular arteries among the different evaluated breeds. Moreover, the presented values attributed to blood flow dynamics can serve as parameters in future studies and can be used to identify alternative diagnostic tools for infertility or to understand issues of adaptability in bulls.

Phenotypic and genotypic characteristics on calves' sale price on the western border of the state of Rio Grande do Sul, Brazil / Impacto de características fenotípicas e genotípicas no preço de venda de bezerros na fronteira oeste do Rio Grande do Sul, Brasil

ABSTRACT: The demand for beef cattle with specific traits is evident from sales in auctions. While purchasing, buyers consider individual traits (e.g., muscularity, frame, racial composition, and weight) as predictors of quality, and adjust their bids according to their preferences. The present study aimed to evaluate the effect of phenotypic and racial characteristics in determining the final sale price of calves of beef cattle in official auctions at the western border of the state of Rio Grande do Sul, Brazil. Five-hundred and seven lots of calves sold in calf auctions from five cities on the western border of Rio Grande do Sul were evaluated. The assignment of visual scores was based on their genetic group, frame, muscularity, and coat. Analysis of variance and the Tukey test at 5% significance level were performed for comparing the final average prices. Variables with the greatest impact on price were the genetic group and the size of the animals. Animals of synthetic breeds obtained higher value in the three years studied and animals without racial definition showed considerable devaluation and a decrease in supply. Larger animals had less value.

RESUMO: A busca por animais com características específicas é evidenciada na comercialização em leilões, em que, ao analisar os animais, compradores consideram as características individuais (musculosidade, frame, composição racial, peso) como preditor de qualidade e ajustam seus lances conforme suas preferências. Dessa forma, o presente estudo buscou avaliar o impacto de características fenotípicas e de padrão racial na composição do preço final de venda de bezerros comercializados em feiras oficiais na fronteira oeste do Rio Grande do Sul. Foram avaliados 507 lotes de bezerros comercializados nas feiras de terneiros de cinco municípios da região da Fronteira Oeste do estado do Rio Grande do Sul. Para a atribuição de escores visuais, considerou-se grupo genético, frame, musculosidade e pelagem dos animais. Foi realizada a análise de variância e a comparação dos preços finais médios pelo teste de Tukey a 5% de significância. As variáveis de maior impacto no preço foram grupo genético e tamanho dos animais. Animais de raças sintéticas obtiveram valorização superior nos três anos Estudados, considerável desvalorização e queda na oferta de animais sem definição racial. Os menores valores foram atribuídos a animais de tamanho grande.

A meta-analysis of cortisol concentration, vocalization, and average daily gain associated with castration in beef cattle.

A systematic review and meta-analysis (MA) were performed to summarize all scientific evidence for the effects of castration in male beef cattle on welfare indicators based on cortisol concentration, average daily gain (ADG), and vocalization. We searched five electronic databases, conference proceedings, and experts were contacted electronically. The main inclusion criteria involved completed studies using beef cattle up to one year of age undergoing surgical and non-surgical castration that presented cortisol concentration, ADG, or vocalization as an outcome. A random effect MA was conducted for each indicator separately with the mean of the control and treated groups. A total of 20 publications reporting 26 studies and 162 trials were included in the MA involving 1814 cattle. Between study heterogeneity was observed when analysing cortisol (I2=56.7%) and ADG (I2=79.6%). Surgical and non-surgical castration without drug administration compared to uncastrated animals showed no change (P≥0.05) in cortisol level. Multimodal therapy for pain did not decrease (P≥0.05) cortisol concentration after 30min when non-surgical castration was performed. Comparison between surgical castration, with and without anaesthesia, showed a tendency (P=0.077) to decrease cortisol levels after 120min of intervention. Non-surgical and surgical castration, performed with no pain mitigation, increased and tended to increase the ADG by 0.814g/d (P=0.001) and by 0.140g/d (P=0.091), respectively, when compared to a non-castrated group. Our MA study demonstrates an inconclusive result to draw recommendations on preferred castration practices to minimize pain in beef cattle.

Performance of beef heifers supplemented with sodium lasalocid.

This study was conducted on 78 13-month-old crossbred beef heifers that weighed 215 kg in Southern Rio Grande do Sul (RS) State, Brazil. We evaluated the performance of beef heifers that were reared in a pasture system that received a mineral supplement energy-type protein with added sodium lasalocid (LAS). The heifers were randomly and uniformly divided into 2 groups, with 39 animals in each group. One group of animals received a mineral supplement energy-type protein without sodium lasalocid (CON), and the other group received a mineral supplement energy-type protein with added LAS. The mean feed intake, the body weight (BW), the average daily gain (ADG), the body condition score (BCS), and ovarian cyclicity were recorded, and economic parameters were calculated. No differences in supplement intake were observed between the groups, which ensures adequate intake of the other components of the mineral mixture, which are part of the nutritional requirements for the production process. Similarly, no difference in the ADG was observed between treatments. We observed that the heifers in the LAS group had a higher BW gain (51 kg) that the CON heifers (40 kg; P < 0.05). In addition, LAS-supplemented heifers had a higher BCS (3.53) than CON heifers (3.38) at the end of the experiment (P < 0.05). The heifers supplemented with LAS had a higher profitability than the CON heifers, even with the higher cost of the supplement containing LAS; this effect was due to the higher live BW at the end of the study. We concluded that the administration of a mineral supplement energy-type protein with added LAS has beneficial effects on beef heifers in terms of production and economic feasibility.

Effects of ambient air temperature, humidity, and wind speed on seminal traits in Braford and Nellore bulls at the Brazilian Pantanal.

The aim of this study was to evaluate the bioclimatic thermal stress assessed by Equivalent Temperature Index (ETI) and Temperature Humidity Index (THI) on Braford and Nellore bulls sperm quality during the reproductive seasons at the tropical region in the Brazilian Pantanal. We used 20 bulls aged approximately 24 months at the beginning of the study. Five ejaculates per animal were collected using an electroejaculator. Temperature, air humidity, and wind speed data were collected every hour from the automatic weather station at the National Institute of Meteorology. Infrared thermography images data were collected to assess the testicular temperature gradient in each animal. Data were analyzed with ANOVA using MIXED procedure of SAS and means were compared using Tukey's HSD test. The THI and ETI at 12 days (epididymal transit) were higher in January (89.7 and 28.5, respectively) and February (90.0 and 29.0, respectively) compared to other months (P < 0.01). Total seminal defects differ only in Bradford bulls between the months of November and February. Nellore bulls had lower major defects (MaD) and total defects (TD) compared to Braford. Nellore bulls showed correlation between minor defects (MiD) and THI for 30 days (0.90) and 18 days (0.88; P < 0.05). Braford bulls showed correlation for MaD (0.89) in ETI for 12 days (P < 0.05). Infrared thermography showed no difference between animals. Reproductive response to environmental changes is a consequence of Nellore and Braford adaptation to climate stress conditions. Both THI and ETI environmental indexes can be used to evaluate the morphological changes in the seminal parameters in Nellore or Braford bulls; however, more experiments should be performed focusing on larger sample numbers and also in reproductive assessment during the consecutive years to assess fertility potential.

Dynamics of Cattle Production in Brazil.

Movement of livestock production within a country or region has implications for genetics, adaptation, well-being, nutrition, and production logistics, particularly in continental-sized countries, such as Brazil. Cattle production in Brazil from 1977 to 2011 was spatialized, and the annual midpoint of production was calculated. Changes in the relative production and acceleration of production were calculated and spatialized using ARCGIS®. Cluster and canonical discriminant analyses were performed to further highlight differences between regions in terms of cattle production. The mean production point has moved from the Center of Minas Gerais State (in the southeast region) to the North of Goiás State (in the Midwest region). This reflects changes in environmental factors, such as pasture type, temperature and humidity. Acceleration in production in the northern region of Brazil has remained strong over the years. More recently, "traditional" cattle-rearing regions, such as the south and southeast, showed a reduction in growth rates as well as a reduction in herd size or internal migration over the period studied. These maps showed that this movement tends to be gradual, with few regions showing high acceleration or deceleration rates.

The uses of infrared thermography to evaluate the effects of climatic variables in bull's reproduction.

The objective of this study was to evaluate the seasonal effects of the environment on sperm quality in subtropical region determined by temperature and humidity index (THI). We used 20 Brangus bulls (5/8 Angus × 3/8 Nellore) aged approximately 24 months at the beginning of the study. Semen evaluations were performed twice per season during 1 year. Climate THI data were collected from an automatic weather station from the National Institute of Meteorology. Infrared thermography images were used to determine the temperature of the proximal and distal poles of the testis to assess the testicular temperature gradient (TG). The seasonal effects on seminal and climatic variables were analyzed with ANOVA using MIXED procedure of SAS. Sperm motility in spring (60.1%), summer (57.6%), and autumn (64.5%) showed difference compared to winter (73.0%; P < 0.01). TG was negatively correlated with THI at 18 days (spermiogenesis) (-0.76; P < 0.05) and at 12 days (epididymal transit) (-0.85; P < 0.01). Ocular temperature (OcT) had a positive correlation with THI at 18 days (0.78; P < 0.05) and at 12 days (0.84; P < 0.01). Motility showed a negative correlation with THI only at 18 days (-0.79; P < 0.05). During spermiogenesis, the TG had higher negative correlation compared to OcT (-0.97; P < 0.01) and rectal temperature (-0.72; P < 0.05). Spermatozoa with distal midpiece reflex were correlated with THI during transit epididymis (0.72; P < 0.05). Seminal parameters are not affected when THI reaches 93.0 (spermiogenesis) and 88.0 (epididymal transit). We concluded that infrared thermography can be adopted as an indirect method in order to assess the effect of environmental changes in TG and OcT of Brangus bulls.

Technologies that affect the weaning rate in beef cattle production systems.

We investigated the differences between weaning rates and technologies adopted by farmers in cow-calf production systems in Rio Grande do Sul State, Brazil. Interviews were carried out with 73 farmers about 48 technologies that could affect reproductive performance. Data were analyzed by multivariate analysis using a non-hierarchical cluster method. The level of significance was set at P < 0.05. Three distinct clusters of farmers were created (R (2) = 0.90), named as low (LWR), intermediate (IWR), and high (HWR) weaning rate, with 100, 91, and 96 % of the farmers identified within their respective groups and average weaning rates of 59, 72, and 83 %, respectively. IWR and HWR farmers used more improved natural pasture, fixed-time artificial insemination, selection for birth weight, and proteinated salt compared to LWR. HWR farmers used more stocking rate control, and IWR farmers used more ultrasound to evaluate reproductive performance compared to the LWR group. IWR and HWR adopted more technologies related to nutrition and reproductive aspects of the herd in comparison to LWR. We concluded that farmers with higher technology use on farm had higher weaning rates which could be used to benefit less efficient farmers.

Competitiveness levels in cattle herd farms / Competitividade em propriedades com criação de bovinos

The aim of this experiment was to identify improvement demands for farms with different levels of competitiveness in the west of Rio Grande do Sul state, Brazil. A total of 63 owners of large farms were interviewed (farms with an area greater than 900ha) by applying a semi-structured questionnaire, guided by four drivers: technology (TEC), management (MAN), market relations (MR) and the institutional environment (IE).It was used the Statistical Analysis System 9.2 software to perform the cluster analysis and identify farmers' characteristics. Three random clusters with different levels of competitiveness were observed: low competitiveness level (LCL), middle competitiveness level (MCL) and high competitiveness level (HCL). The 29 variables (sub factors) were evaluated in the cluster analysis according to level of impact on competitiveness, being classified into variables of high, medium or low impact. Stratification was carried out, ranking demands for improvements from aspects attributed by experts in relation to sub factors. The farmers with low competitiveness level (LTL) had an unfavorable status for MAN, while the farmers belonging to clusters MCL and HCL have, respectively, favorable and neutral status for the same driver. The management characteristics determined the level of competitiveness of the farms surveyed.

O objetivo deste experimento é a identificação das demandas de melhorias para fazendas com diferentes níveis de competitividade no Oeste do RS. Entrevistaram-se 63 produtores grandes (área= +900 ha) por meio de um questionário semi-estruturado, dividido em quatro direcionadores: tecnologia (TEC), gestão (MAN), relações de mercado (MR) e ambiente institucional (IE). Utilizou-se o software SAS 2002, versão 9.0, para realização da análise de cluster, realizando a tipologia dos produtores. Nesta análise, formaram-se aleatoriamente três clusters, sendo denominados de baixo nível de competitividade (LCL), médio nível de competitividade (MCL) e alto nível de competitividade (HCL). Dividiram-se as 29 variáveis (subfatores) avaliadas na análise de cluster de acordo com nível de impacto na competitividade das fazendas de bovinos de corte, sendo classificadas em variáveis de alto, médio ou baixo impacto. Esta estratificação do ranking de demanda de melhorias foi realizada a partir dos pesos atribuídos pelos especialistas aos subfatores. Os pecuaristas com baixo nível de competitividade apresentaram status desfavorável para MAN, enquanto os pecuaristas pertencentes aos clusters MCL e HCL apresentaram, respectivamente, status neutro e favorável para o mesmo direcionador. Portanto, a gestão é determinante para definir o nível de competitividade das fazendas entrevistadas.

Scrotal infrared digital thermography as a predictor of seasonal effects on sperm traits in Braford bulls.

The aim of this study was to assess the seasonal effects of the environment on semen quality in bulls, using infrared thermography. Sperm motility (M), mass motion (MM), and vigor (VIG) were evaluated in sperm samples from 17 Bradford bulls aged approximately 24 months at the beginning of the study. Infrared thermography images and data were collected using an infrared FLIR T 300 camera and Quick Report 1.2 SP2 software to determine the temperature of the proximal and distal poles of the testis and to assess the testicular temperature gradient. The seasonal effects on physiological, seminal, and climatic variables were analyzed by the GLM ANOVA and CORR procedures using SAS®. The microclimatic factors were recorded in hourly intervals, and the daily mean temperature and mean relative humidity were calculated to determine the daily temperature-humidity index (THI) every day for 1 year. The temperature gradient (TG) variations of the testes were significantly higher in the autumn (4.5 °C), winter (4.0 °C), and spring (2.9 °C) compared to summer (0.9 °C) (P < 0.05). Ocular globe temperatures were lower in the winter (27.6 °C) and autumn (26.8 °C) compared to summer (33.9 °C) and spring (31.1 °C) (P < 0.05). The average MM (2.58), M (52.64), and VIG (2.70) of the semen decreased in the summer compared to other seasons (P < 0.01). The TG was negatively correlated with THI (-0.44; P < 0.05). For the seminal variables, MaD (-0.45; P < 0.05) and TD (-0.50; P < 0.01) presented a negative correlation with TG. The TG had a positive correlation between M and VIG, which had values of 0.36 and 0.35, respectively (P < 0.05). We have concluded that infrared thermography can be used to assess the testicular temperature gradient and its consequences on physical and quantitative aspects of sperm.

Higher feeding diets effects on age and liveweight gain at puberty in crossbred Nelore × Hereford heifers.

This study was conducted to determine the age and liveweight at puberty of 120 crossbred beef heifers submitted to four diets to achieve predetermined weight gains (kg/day): 0.5 (G500; n = 32), 0.75 (G750; n = 32), 1.0 (G1000; n = 29), and 1.25 (G1250; n = 27). Animals were classified depending on their level of crossing between Nelore (N) and Hereford (H): 25%N-75%H, 37.5%N-63.5%H, 43.7%N-56.7%H, 50%N-50%H, and 75%N-25%H. Reproductive evaluation was performed at the beginning and at the end of the experimental period by ultrasonography and hormone analysis. The average age and liveweight at puberty were 388.0 ± 1.9 days and 331.4 ± 1.3 kg, respectively. Animals from the 25%N-75%H group reached puberty earlier than heifers from other genetic groups supplemented with G1250 diet (P < 0.05). Heifers with higher degree of Nelore (75%N-25%H) fed with G1000 diet showed estrus 42 days prior to mating, but only 57% reached puberty at mating (P < 0.05). Heifers with follicles of higher diameter reached puberty (P < 0.05) earlier. Higher average daily weight gain showed a positive effect on follicular diameter and IGF-I level at puberty (P < 0.01). Concentrations of GH were lower in heifers fed G1250 compared to G1000 diet (P < 0.05). There was a significant interaction between nutritional level and insulin levels at puberty (P < 0.01). We demonstrated the relationship between IGF-I and average daily gain on the onset of puberty in heifers. In conclusion, heifers submitted to the higher feeding level showed a higher follicular diameter and were younger at puberty.