Food Science, Agricultural and Biological Sciences, Food Animals, General Veterinary
27
Scopus Publications
Scopus Publications
Effect of weaning age on pregnancy rates in Braford beef heifers bred at 13 months Maria Eduarda Cocco Dallanóra, José Fernando Piva Lobato, Javier Alexander Bethancourt-Garcia, Mariana Assis Borges, Rangel Fernandes Pacheco, João Restle, Ricardo Zambarda Vaz Animal Reproduction, 2026 The aim of this study was to evaluate the probability of pregnancy in heifers weaned at different ages and bred at 13 to 15 months old. A total of 121 Braford heifers were used, weaned as calves at 77 days (early) or 147 days (conventional) of age. To develop the statistical models of reproductive performance, factors related to the development of the heifers were analyzed. The analysis included a diagnosis of multicollinearity using the Pearson correlation matrix, adjusting the model by means of the Hosmer and Lemeshow test. The response variable, rate of pregnancy, was analysed using the LOGISTIC procedure. Beginning with a weight of 271 kg and an age of 402 days at the start of the breeding season, the pregnancy rates increased by 18.4% and 29.0%, respectively for every 15 kg increase in body weight and 10-day increase in age. However, a reduction of 15 kg in body weight and of 10 days in age reduced the pregnancy rates in the heifers by 15.5% and 22.5%. An increase or reduction of 0.100 kg in the average daily gain between early weaning and conventional weaning represented an increase of 44.6% and a reduction of 30.9% in the chances of pregnancy. Early-weaned heifers require correct nutritional management to allow satisfactory postweaning weight gains so as not to compromise their reproductive performance.
Grazing management of Panicum maximum cvv. Mombaça and Tanzania pastures for beef cattle: a meta-analytic study Lucas Mateus de Souza Mota, Bruno Henrique Martines Cezar, Odilene de Souza Teixeira, Raul Dirceu Pazdiora, Alice Munz Fernandes, Gleimiria Batista da Costa Matos, Ana Karina Dias Salman, Diego Soares Machado, Rangel Fernandes Pacheco, Isabelle Damé Veber Angelo Crop and Pasture Science, 2024 Context The future of livestock farming is based on grazing management practices that balance using natural resources and forage technical efficiency for cattle. Aims This study aimed to investigate the bromatological characteristics and cattle performance under continuous and intermittent stocking systems in Panicum maximum cvv. Mombaça and Tanzania pastures, as well as identify the appropriate height for managing these forages. Methods A systematic review and meta-analysis were used from selecting studies available in scientific article format in electronic databases: Google Scholar, ISI Web of Science, and PubMed. We identified 4691 documents, of which 13 were submitted to meta-analysis. Key results Tanzania pasture presented 564.25 ± 38.56 g kg−1 of leaf biomass dry matter (DM) and 3.09 ± 0.34 of leaf stem−1 ratio in intermittent stocking system, which was higher than continuous system, with values of 313.10 ± 38.56 g kg−1 DM (P = 0.0380) and 1.04 ± 0.34 (P = 0.0216), respectively. Animals’ average daily gain was greater in continuous stocking system than intermittent system, with values of 0.91 kg day−1 and 0.67 kg day−1, respectively. Additionally, post-grazing height ≥31 cm for Tanzania increased average daily gain by 28.3% (P = 0.0263), and height ≥39 cm for Mombaça increased average daily gain by 38.1% (P = 0.0002). Conclusions Post-grazing residues from the intermittent method or constant pasture height from the continuous method are the main indicators for adapting pasture management. Therefore, grazing management at heights between ≥31 and 39 cm for Tanzania and Mombaça is promising for animal performance. Implications Results provide subsidies for decision making regarding grazing management to maximise animal productivity.
A meta analysis on carcass and meat traits of feedlot steers from different genetic backgrounds in Brazil Rangel Fernandes Pacheco, Jullia Sehorek Teixeira, Bruna Seger da Silva Pinheiro, Murilo Colucci Souza, Brunna Ferraz Dreher, Gabriel Luis Werner Kerkhoff, Laura Mezzomo Donatti, Brenda Baptista França, Odilene de Souza Teixeira, Ricardo Zambarda Vaz Ciencia Animal Brasileira, 2024 The aim of the present study was to assess the carcass and meat characteristics of feedlot steers in Brazil according to genetic group through a systematic review and meta-analysis. An electronic article search was conducted at the Scielo and Google Scholar databases and data were grouped according to genetic predominance. The results were tested for heterogeneity and submitted to a normality test and F test and the means were compared by the Tukey test. Predominantly British steers were finished at a younger age, required longer confinement times and displayed lower hot carcass weights and smaller loin eye areas at slaughter. Muscle carcass percentages were higher in Continental and Synthetic steers compared to British and Zebu steers, while fat percentages were higher in British and Zebu steers compared to continental and synthetic breeds. Meat marbling was higher in British, continental and crossbreed steers compared to synthetic and zebu steers. A British steer origin allows for decreased slaughter age, although leading to reduced hot carcass weight, while a genetic Zebu predominance can produce high fat percentage carcasses.
Meta-analysis of meat quality of cattle slaughtered with different subcutaneous fat thicknesses Rangel Fernandes Pacheco, Diego Soares Machado, João Restle, Dayana Bernardi Sarzi Sartori, Pablo Tavares Costa, Ricardo Zambarda Vaz Pesquisa Agropecuaria Brasileira, 2023 The objective of this work was to evaluate, through meta-analysis, the impact of subcutaneous fat thickness on beef qualitative traits. Combined data from 13 studies were used, comprising 245 carcasses of male bovines slaughtered in Brazil. Effect size for all parameters was calculated as mean difference or standardized mean difference, at 95% probability. The meta-analysis of random and fixed effects was carried out when I2>50% and I2<50%, respectively, for each indicator separately, with means for fat thickness, classified in the “control” (3–6 mm), “low” (<3 mm), and “high” (>6 mm) groups. Carcasses in the “high” group showed greater intramuscular fat deposition, whereas those in the “low” group presented an intramuscular fat deposition similar to that of the control. When the fat thickness was below the recommended threshold of 3 mm, shear force increased. Subcutaneous fat thickness values greater than 6 mm induced a positive change in the perception of tenderness by the panel of evaluators. Beef carcasses with a subcutaneous fat thickness over 6 mm tend to accumulate more intramuscular fat content and are tenderer for consumers’ acceptance. Carcasses with a fat thickness less than 3 mm produce tougher meat.
Effect of the performance, calving date and lactation period on the probability of pregnancy in beef cows Nathália Pasi Reis, José Fernando Piva Lobato, João Restle, Rangel Fernandes Pacheco, Amoracyr José Costa Nuñez, Dayana Bernardi Sarzi Sartori, Ricardo Zambarda Vaz Scientia Agricola, 2023 Determining what and how much each environmental factor affects pregnancy is crucial to the sustainability and management of beef cow herds. The study evaluated through logistic regression the effect of environmental variables on the increase or reduction in the pregnancy rate of beef cows. The average pregnancy rate in the cows was 73 %, with an average age for the herd of 3.7 years. An increase in age of one year represented a 30 % increase in pregnancy, while a reduction of one year reduced the odds of pregnancy in the cows by 23 %. During the lactation period, an extra seven days’ lactation reduced the odds of pregnancy by 12 %. For every seven days that weaning was brought forward, the cows’ pregnancy odds increased by 14 %. An increase of 0.1 kg in average daily gain represented an increase of 17 % and 15 % in the odds of pregnancy during the first 60 days post-partum and 60 days to the end of the reproductive period. On the other hand, the loss of 0.1 kg in average daily gain resulted in a 14 % and 13 % reduction in the cows’ pregnancy odds, respectively. Factors such as age, the precocity of calving in the calving season, the time the calf remains with the cow and better performance in cows between calving and the end of the mating are strategies that increase the chances of pregnancy in beef cows.
Environmental factors on the probability of pregnancy in early or conventionally weaned beef cows Ricardo Zambarda Vaz, José Fernando Piva Lobato, Javier Alexander Bethancourt-Garcia, Rangel Fernandes Pacheco, Nathália Pasi Reis, Dayana Bernardi Sarzi Sartori, Sabrina Amália Jappe, João Restle Animal Reproduction, 2023 Potential variables for the reproductive success of beef cows were evaluated. Included in the model were the age of the cow at calving; the interval between the Julian calving date and the end of the breeding season; the body weight and conditions at calving, at 75 days post-partum and at the end of the breeding season; and the mean daily variation in weight between these dates. Logistic regression was used in the analysis, with the parameters evaluated using the odds ratio statistic, estimating the chance of pregnancy. The mean rate of pregnancy was 84% and 55% for early and late-weaned cows, respectively. For early weaned cows, the regression variables were the Julian calving date, age of the cow, weight gain from calving to 75 days post-partum, and from 75 days post-partum to the end of the reproductive period. For late-weaned cows, there were only two regression variables, weight at calving and weight gain from calving to the end of the reproductive period. For every year above the average age of the herd, early weaned cows have an 80.9% greater chance of pregnancy, while a reduction of one year reduces the chance of pregnancy by 44.7%. In early weaned cows, every seven days after the mean Julian calving date reduces the chances of pregnancy by 22.6%, whereas every seven days before the mean calving date increases pregnancy by 29.2%. Greater gains in cow body weight, from calving to the end of the reproductive period, determine a greater probability of pregnancy.
Body mass index at calving on performance and efficiency of Charolais cow herds Ricardo Zambarda Vaz, Liliane Cerdótes, Amoracyr José Costa Nuñez, Dayana Bernardi Sarzi Sartori, Rangel Fernandes Pacheco, Hítalo Rodrigues da Silva, Javier Alexander Bethancourt-Garcia, João Restle Tropical Animal Health and Production, 2022
Probability of pregnancy in beef cows with early-weaned calves Rangel Fernandes Pacheco, Ricardo Zambarda Vaz, João Restle, Magali Floriano da Silveira, Liliane Cerdotes, Jullia Sehorek Teixeira, Lucas Milani, Paulo Santana Pacheco Livestock Science, 2022
Body mass index at calving on performance and efficiency of Zebu cow herds , Ricardo Zambarda Vaz, Liliane Cérdotes, , Rangel Fernandes Pacheco, , Dayana Bernardi Sartori, , Jeniffer Danielle Lucas, , Hilda Solange Souza Agner, , João Restle, and Semina Ciencias Agrarias, 2022 This study examines the impact of the body mass index (BMI) at calving on the development and postpartum efficiency of cows of Zebu origin. The study involved 87 cows and their calves [pure Nellore (N) or predominant Nellore composition in a cross with Charolais (C) (3/4N1/4C and 5/8N3/8C)]. The mothers were grouped into classes according to their BMI at calving, namely, ‘small’, ‘moderate’ and ‘large’. Body mass index was determined by dividing the body weight of the cows by their length and by hip height and then dividing the result by 10. Cows were weighed at calving, at weaning, at the end of the breeding period and at the diagnosis of pregnancy. Calves were weighed at birth, at early weaning (63 days) and at 210 of age. To evaluate milk yield and quality, milk was collected at 21, 42 and 63 days after calving. Milk yield was measured by the direct method, with manual milking, followed by analysis of the lactose, fat, total solids and crude protein contents. Pregnancy rate was similar between the three BMI groups; however, cows with a lower BMI were more efficient at calving in producing kilograms of calf per kilogram of cow kept. Higher BMI provide higher milk yields, without affecting its quality, as well as heavier calves at early weaning and at 210 days of age.
