Search Results (33)

The inclusion of meat quality traits in breeding programs is a promising strategy to improve beef by selecting animals based on both growth and meat quality. This study aimed to estimate genetic parameters for average daily gain (ADG) and Warner–Bratzler shear force (WBSF), as well as to perform genome-wide association studies (GWAS) to identify genomic regions and transcription factor (TF) binding sites associated with both traits in Nelore cattle. Genetic parameters were estimated using a bi-trait Bayesian model, and GWAS identified key SNPs explaining over 1% of variance in genomic estimated breeding values. Candidate genes near these SNPs were annotated, TF binding sites predicted, and gene–TF networks constructed. Genetic estimates indicated moderate heritability for ADG, low heritability for WBSF, and a small negative genetic correlation between traits. Genomic regions contained 116 and 151 candidate genes for ADG and WBSF, respectively, with 35 shared between traits. Functional analyses highlighted MYBPC1 and PENK for WBSF, and GHRS and NPY for ADG. TF analysis identified 25 TFs, with 3 key ones highlighted. Gene–TF networks revealed candidates including CAPN1 and LTBP3 for WBSF, and CARM1 and GH1 for ADG. Shared candidate genes identified in the combined network provide valuable insights into the genetic architecture of growth and tenderness in Nelore cattle. Full article

The scientific literature currently lacks studies that evaluate the nutritional composition of the tissues of cattle raised in different systems, so that the nutritional effects can be known and used to enhance consumption and use in the diet. The aim was therefore to assess whether the mineral content of muscle tissue (longissimus lumborum) in cattle finished during the rainy season in the Eastern Amazon is influenced by different farming systems. The treatments consisted of four systems (three pasture production systems and one feedlot system). 1. native wetland pasture in Santa Cruz do Arari (Mesoregion of Marajó); 2. native wetland pasture in Monte Alegre (Mesoregion of Baixo Amazonas); 3. cultivated dryland pasture in São Miguel do Guamá (Mesoregion of Nordeste Paraense); and 4. Confinement in Santa Izabel do Pará (Metropolitan Region of Belém). The analyses were carried out on samples of the longissimus lumborum muscle tissue of 48 male, castrated, crossbred Nelore cattle, twelve per breeding system, from commercial farms, destined for meat production, finished during the rainiest period of the year (between January and June). In systems 1 and 2, the animals were slaughtered in licensed slaughterhouses; the animals in systems 3 and 4 were slaughtered in commercial slaughterhouses. Food sampling and chemical analysis, soil sample collection and analysis, longissimus lumborum muscle tissue collection, sample preparation and digestion, and inductively coupled plasma optical emission spectrometry were evaluated. The experimental design was completely randomized in a linear model with four rearing systems and one period (rainy). The data was compared using the Statistical Analysis Systems (SAS) program. All analyses were carried out considering a significance level of 0.05. Samples of the diets offered (pasture and concentrate) were also collected. The Amazon systems influenced the macro- and micromineral content in the muscles of cattle (p < 0.05). The interaction between pasture systems vs. confinement showed differences in the minerals calcium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) (p < 0.05). However, there was no difference in the values of sodium (Na), potassium (K), and sulfur (S) between the rearing systems (p > 0.05). By contrast, the cultivated pasture system vs. extensive pasture showed differences in all the elements evaluated (p < 0.05). The rearing systems of the Eastern Amazon influenced the mineral content of beef, which continues to be an excellent source of macro- and microminerals and can compose the human diet. Full article

Maternal nutrition’s impact on liver transcriptome in beef cattle offspring is still underexplored. We investigated the long-term effects of maternal nutrition strategies on the liver transcriptome of pre-slaughter Nelore bulls. Pregnant cows were divided into three groups, each receiving different nutritional regimens: NP (control, only mineral supplementation), PP (late gestation protein–energy supplementation), and FP (protein–energy supplementation throughout pregnancy). Liver samples were collected from male offspring aged 22.5 ± 1 months and analyzed using RNA-Seq (n = 5 per treatment). Principal component analysis (PCA) and differential gene expression analysis were carried out in an R statistical environment. Genes were considered significant when FDR < 0.05. The over-representation analysis (ORA) was performed using the clusterProfiler package from R. Metabolic pathways were considered significant when the Q-value < 0.1. The PCA showed overlapping clusters among the groups. We identified 16 differentially expressed genes (DEGs) associated with PP × NP contrast, four with FP × NP, and two with FP × PP. The ORA revealed two significant pathways (thiamine and butanoate metabolism). The identified genes and pathways were associated with vitamins, energy, oxidative metabolism, and immune function. This study emphasizes the more significant long-term effects of the PP treatment on the offspring’s liver transcriptome compared to the FP treatment. Full article

We aimed to evaluate the reproductive efficiency of Nelore cows in fixed-time artificial insemination (FTAI) programs with early resynchronization. A total of 468 Nelore cows were divided into two experimental groups: R30—conventional resynchronization at 30 days (n = 234); R22—early resynchronization at 22 days (n = 234). Both groups followed a synchronization protocol using intravaginal progesterone devices combined with the administration of steroids and gonadotropins. The R30 protocol involved resynchronization 30 days after FTAI, while the R22 protocol implemented early resynchronization 22 days after FTAI without prior pregnancy diagnosis. In both groups, one FTAI was followed by two resynchronizations. The results showed similar pregnancy rates between the groups, with the pregnancy rate in the 1st FTAI being 50.85% in the R30 group and 48.72% in the R22 group (p = 0.742). During the 1st resynchronization, the rates were 45.22% in the R30 group and 46.67% in the R22 group (p = 0.742). The cumulative pregnancy rate after the 1st FTAI, 1st, and 2nd resynchronizations was 80.77% in the R30 group and 82.91% in the R22 group (p = 0.643), with no significant difference observed. Follicular dynamics were also monitored, with ovulation occurring in 78.95% of cases in the 1st FTAI, 91.67% in the 1st resynchronization, and 88.98% in the 2nd resynchronization. The mean diameter of the ovulatory follicle was 13.64 ± 3.48 mm, and the largest follicle diameter was significantly greater (14.47 ± 2.76 mm) in cows that ovulated compared to those that did not (11.54 ± 4.24 mm) (p < 0.05), reinforcing the association between follicle size and the likelihood of ovulation. These findings indicate that both early and conventional resynchronization protocols perform similarly, with early resynchronization offering advantages in reducing the calving interval. Furthermore, the relationship between follicular diameter and ovulation confirms the importance of follicle size as an indicator of reproductive success. Full article

The veal niche market is gaining momentum in Brazil. Locally known as ‘Vitelão’, veal refers to the meat from calves slaughtered up to 12 months of age. In this study, we assessed the Galician Blond × Nelore cross as a candidate to produce veal. The aim of this study was to establish criteria for selecting 12-month-old calves suitable for slaughter. To find the best fit, we adjusted various growth models for calves up to 12 months of age. Once the best fit was determined, the selected growth model was then used to calculate the relative and instantaneous growth rates to evaluate the slaughtering potential at 12 months. Our study reveals that, under present conditions, the Logistic model is the best fit for characterizing and functionally analyzing growth from birth to 12 months of age in Galician Blond crosses with Nelore. Calves resulting from this cross experience rapid growth in their first 12 months of life, making them an excellent choice for producing high-quality veal while maintaining rusticity and adaptability to extreme environments. The results of this study could contribute to enhancing the growth management systems of Galician Blond and Nelore crosses in Brazilian grazing production systems. Additionally, they can be incorporated into genetic improvement programs as a tool for selecting animals with greater precocious growth without altering adult weight. Full article

This study explores the use of a Siamese neural network architecture to enhance classification performance in few-shot learning scenarios, with a focus on bovine facial recognition. Traditional methodologies often require large datasets, which can significantly stress animals during data collection. In contrast, the proposed method aims to reduce the number of images needed, thereby minimizing animal stress. Systematic experiments conducted on datasets representing both full and few-shot learning scenarios revealed that the Siamese network consistently outperforms traditional models, such as ResNet101. It achieved notable improvements, with mean values increasing by over 6.5% and standard deviations decreasing by at least 0.010 compared to the ResNet101 baseline. These results highlight the Siamese network’s robustness and consistency, even in resource-constrained environments, and suggest that it offers a promising solution for enhancing model performance with fewer data and reduced animal stress, despite its slower training speed. Full article

The objective of this study was to evaluate the effect of different nutritional strategies on the intensification of beef cattle farming on pastures during the dry period of the year. Eighty male cattle (testers) were randomly allocated to 16 paddocks formed with Mombaça grass (Megathyrsus maximus), totaling five animals (testers) per paddock. The strategies consisted of two LCs [10 and 16.7 g·kg⁻¹ body weight (BW)] and two PSs with DDGS and SBM in a completely randomized design with a 2 × 2 factorial arrangement. The chemical, structural, and productive characteristics of the forage were evaluated, as well as the performance, productivity, and serum parameters of the supplemented animals. The forage presented a greater L:C (p = 0.033) and CP content (p = 0.007) when the lowest LC was used. Animals that received the highest LC had the highest supplement intake (p < 0.001) and the lowest pasture intake (p < 0.001). The nutritional strategy with an LC of 16.7 g·kg⁻¹ of body weight (BW) resulted in a greater increase in total BW, i.e., 200 kg·BW ha⁻¹ more. Therefore, higher levels of concentrate ensure greater productivity for beef cattle grazing, and DDGS can replace SBM in supplements used in the intensive raising of beef cattle on pasture without compromising the performance and productivity of the animals. Full article

The evaluation of the reactivity and distress of cattle during corral management, by means of subjective scores, aims at the standardization of behavioral indicators, through non-invasive methods, in addition to enabling the development of more appropriate management practices, thus promoting the comfort and well-being of these animals. Therefore, in this study, we aimed to characterize the temperament and distress of cattle managed in a corral using behavioral indicators during the rainiest period. For this, the experiment was conducted on a property located in the municipality of Mojuí dos Campos, during the rainiest quarter (February–April). Thus, 30 male cattle, not castrated, approximately 29 months of age, clinically healthy, and weighing 310 + 20 kg, were divided into three rearing systems: silvopastoral (SP), traditional (SS), and integrated (SI) systems. There were 10 animals per system. Physiological parameters were collected to evaluate rectal temperature (RT) and respiratory rate (RR), as well as body surface temperature (BST), through thermal windows (head and flank infrared temperature and rump infrared temperature). To evaluate temperament and reactivity, scores indicative of corral behavior were used, namely escape speed (ES), tension score (SS_1), tension score (SS_2), reactivity scale (RS), movement score (MS), and temperament scale (TS). The results showed that there was a thermal amplitude of 5.9 °C on average and 8.6 °C at maximum when comparing the structure of the corral and the trees. In addition, the comparisons between the production systems for the behavioral variables did not differ at the 5% significance level, except for ES, where the traditional system differed from the integrated system and the silvopastoral system, showing intermediate average values for both. In addition, there was a positive correlation between the variables RT and RR (r = 0.72; p < 0.01), RR and SS_2 (r = 0.38; p = 0.04), flank infrared temperature and MS (r = 0.47; p = 0.01), rump infrared temperature and RS (r = 0.37; p = 0.04), SS_1 and RS (r = 0.41; p = 0.02), SS_1 and SS_2 (r = 0.39; p = 0.03), RS and SS_2 (r = 0.58; p = 0.00), RS and MS (r = 0.50; p = 0.01), RS and TS (r = 0.61; p = 0.00), SS_2 and MS (r = 0.51; p = 0.00), SS_2 and TS (r = 0.47; p = 0.01), and MS and TS (r = 0.44; p = 0.02), and a negative correlation between ES and TS (r = −0.42; p = 0.02). The rainy season had a major influence on the evaluation of temperature and distress levels during handling in the corral, as evidenced by the association between physiological and behavioral parameters. Full article

The objective of this study was to evaluate the thermal comfort of Nelore cattle (Bos indicus) managed in silvopastoral and traditional systems associated with rumination behavior in a humid tropical environment in the Eastern Amazon, Brazil. The study was carried out on a rural property in Mojuí dos Campos, Pará, Brazil, during the transition period of the year, from June to July 2023. Over these two months, six consecutive data collection days were held. We selected 20 clinically healthy non-castrated male Nelore cattle, aged between 18 and 20 months, with an average weight of 250 kg and body condition score of 3.5 (1–5). These animals were randomly divided into two groups: traditional system (TS) and silvopastoral system (SS). The physiological variables evaluated included RR, RT and BST. The variables were analyzed using the linear mixed model. For agrometeorological variables, higher values were observed between 10:00 a.m. (33 °C) and 6:00 p.m. (30 °C), with the highest temperature observed at 4:00 p.m. (40 °C). The RR showed interactions (p = 0.0214) between systems and times; in general, higher RR were obtained in the Traditional. The animals’ RT showed no significant difference (p < 0.05) between the production systems, but there was a statistically significant difference in relation to the time of collection (p < 0.0001). In the BGHI, it was possible to observe that there was mild stress in the period from 22:00 at night to 6:00 in the morning and moderate stress in the period of greatest increase in temperature, from 10:00 in the morning to 18:00 at night. BST showed no statistical difference between the regions studied or between the SP (35.6 °C) and TS (36.25 °C) systems. RT in the TS showed a positive correlation with AT (r = 0.31507; p = 0.0477). RT in the SP showed a positive correlation with THI (r = 35583; p = 0.0242). On the other hand, RT in the SP (r = 0.42873; p = 0.0058) and ST (r = 0.51015; p = 0.0008) showed a positive correlation with BGHI. RR in the TS showed a positive correlation with BGHI (r = 0.44908; p = 0.0037). The greatest amounts of rumination were carried out by animals in the SP system, generally ruminating lying down (p < 0.05). With regard to rumination behavior in the morning and afternoon, there were higher numbers of WS and LD in the TS (p > 0.05). Most of the time, the cattle were LD during the morning and afternoon shifts, and at night and dawn they were WS in the TS. Therefore, the SP offers more thermal comfort advantages compared to the TS system. Full article

The behavior of ruminants can influence their productive efficiency. The aim of this study was to evaluate the behavior of young zebu and composite bulls kept in pasture production systems, either in a crop-livestock-forest integration or without afforestation. The work was carried out in São Carlos, Brazil (21°57′42″ S, 47°50′28″ W), in a high-altitude tropical climate, from March to July, 2022. Forty young bulls were evaluated, being 20 Nelore (Bos indicus) (342.5 ± 36.6 kg BW; 16.9 ± 1.8 months) and 20 Canchim (5/8 Bos taurus × 3/8 Bos indicus) (338.4 ± 39.8 kg BW; 19.1 ± 1.9 months), equally distributed in full-sun (FS) and integrated crop–livestock–forestry (ICLF) production systems. Behavior was monitored uninterruptedly by an acoustic sensor and accelerometer attached to a collar, and complemented by direct visual assessment, in two one-day campaigns per month. Serum cortisol concentration was assessed monthly. Statistical analyses were conducted using a general linear model at a 5% significance level (SAS, version 9.4). The ICLF system had a milder microclimate and favored thermal comfort. Natural shading influenced grazing, resting, and rumination time. The Canchim bulls were more active when moving and grazing (p < 0.05), even at the hottest times of the day. In turn, the Nelore bulls spent more time resting at all times (p < 0.001), which was shown to be an adaptive strategy in response to environmental stimuli. The Canchim bulls had a longer rumination time than the Nelore bulls (p < 0.001), due to their longer grazing time. The frequency of water and mineral mixture intake did not differ between genotypes, regardless of the production system (p > 0.05). There was no difference in the serum cortisol concentrations of the Nelore and Canchim bulls kept in FS or ICLF (p = 0.082). Thus, young bulls of the different genotypes showed different behaviors, regardless of whether they were kept on pasture without afforestation or in an integrated crop–livestock–forestry system. Full article

Reports on UCF in animals are still lacking in veterinary literature. Detailed clinical signs, laboratory findings, and follow-up information from the first cases of UCF in two ewes and two cows are provided. The cases occurred over a 12-year period. All ruminants presented a fistulous tract or perforated wound on the right ventral abdomen, emitting a foul-smelling secretion possibly associated with macerated fetal parts or placental remains. Laboratory findings included anemia, leukocytosis by neutrophilia, and hyperfibrinogenemia in one ewe, and hyperfibrinogenemia in one cow. Ovariohysterectomy and fistulectomy were performed in one ewe, while the other three ruminants were submitted for the removal of fetal parts and placental remains through the UCF. Two ewes died within 12–48 h, and the two Nelore cows had an uneventful recovery, achieving secondary intention healing within 30 to 35 days. As a never-reported or unnoticed disease of the reproductive tract, UCF is an unusual consequence of dead fetus retention in an end-stage pregnancy and a potentially life-threatening condition in ruminants, especially ewes. Further broad studies in large herds of cattle and small ruminant flocks must be conducted to estimate the incidence of UCF and ensure improvements in the diagnosis and knowledge of pathogenesis, aiming at prevention. Full article

The prenatal environment is recognized as crucial for the postnatal performance in cattle. In tropical regions, pregnant beef cows commonly experience nutritional restriction during the second half of the gestation period. Thus, the present study was designed to analyze the genotype by prenatal environment interaction (G × Epn) and to identify genomic regions associated with the level and response in growth and reproduction-related traits of beef cattle to changes in the prenatal environment. A reaction norm model was applied to data from two Nelore herds using the solutions of contemporary groups for birth weight as a descriptor variable of the gestational environment quality. A better gestational environment favored weights until weaning, scrotal circumference at yearling, and days to first calving of the offspring. The G × Epn was strong enough to result in heterogeneity of variance components and genetic parameters in addition to reranking of estimated breeding values and SNPs effects. Several genomic regions associated with the level of performance and specific responses of the animals to variations in the gestational environment were revealed, which harbor QTLs and can be exploited for selection purposes. Therefore, genetic evaluation models considering G × Epn and special management and nutrition care for pregnant cows are recommended. Full article

Pain assessment guides decision-making in pain management and improves animal welfare. We aimed to investigate the reliability and validity of the UNESP-Botucatu cattle pain scale (UCAPS) and the cow pain scale (CPS) for postoperative pain assessment in Bos taurus (Angus) and Bos indicus (Nelore) bulls after castration. Methods: Ten Nelore and nine Angus bulls were anaesthetised with xylazine–ketamine–diazepam–isoflurane–flunixin meglumine. Three-minute videos were recorded at -48 h, preoperative, after surgery, after rescue analgesia and at 24 h. Two evaluators assessed 95 randomised videos twice one month apart. Results: There were no significant differences in the pain scores between breeds. Intra and inter-rater reliability varied from good (>0.70) to very good (>0.81) for all scales. The criterion validity showed a strong correlation (0.76–0.78) between the numerical rating scale and VAS versus UCAPS and CPS, and between UCAPS and CPS (0.76). The UCAPS and CPS were responsive; all items and total scores increased after surgery. Both scales were specific (81–85%) and sensitive (82–87%). The cut-off point for rescue analgesia was >4 for UCAPS and >3 for CPS. Conclusions. The UCAPS and CPS are valid and reliable to assess postoperative pain in Bos taurus and Bos indicus bulls. Full article

Body weight records were used to characterize the growth curve of Nelore cattle. Body weight was regressed as a function of age, for both sexes, by using nonlinear models through the functions of Brody, Gompertz, Logistic, Richards, Meloun 1, Von Bertalanffy, and Von Bertalanffy. The quality of the model arrangements was evaluated by employing Akaike and Bayesian Schwarz information criteria. The Brody function provided the best adaptations by the evaluators and, considering the asymptotic weight and the maturation rate as random, a reduction in residual variance of 79% for males and 83% for females was obtained in relation to the models under fixed contexts. In males, the absolute and relative growth rates ranged from 0.921 to 0.261 kg/day and 2.39 to 0.08%, respectively. For the same rates, under another approach, females ranged from 0.922 to 0.198 kg/day and 2.55 to 0.06%, respectively. Males showed greater growth acceleration at the beginning of the growth trajectory, being equal to females at 397 days of age and from that age onward they presented lower estimates. The nonlinear regression model approach under the mixed-models context allows reduction of residual variance, increasing model accuracy. Full article

This paper aims to report clinical, laboratory, radiographic, and pathological features in a case of cervical vertebral stenotic myelopathy (CVSM) affecting a 4-month-old Nelore calf for the first time. During physical examination, the calf could stand if assisted when lifting by the tail but fallen to the ground when trying to walk. Attempts to flex and extend the neck to the right side failed. Radiographs findings consisted of reduced intervertebral spaces, and misalignments between the endplates, more evident between the C3 and C4 vertebrae, resulting in narrowing of the spinal canal and compression of the spinal cord. Grossly, C4 showed cranial articular surface malformation, abnormal metaphyseal growth plate development, reduced vertebral body size and deformity. Histologically, C4 showed an abnormal vertebral bone development characterized by moderate replacement of trabecular bone by fibrous tissues, multifocal areas of dystrophic hyaline cartilage development, and cartilaginous growth failure along the metaphyseal growth plate. Cervical spinal cord within the stenotic vertebral canal showed swollen neurons with central chromatolysis, areas of Wallerian degeneration, and necrotic debris. In contrast with the well-known Wobbler syndrome in horses, the etiology of CVSM in cattle remains undetermined, and further genetic and pathological studies must be conducted to elucidate it. Full article