Resumo em Inglês:

ABSTRACT We investigated the impact of weaning at 30, 75, and 180 days of age on performance, body measurements, and rumen development (using the β-hydroxybutyrate biomarker) of beef calves until 190 days of age. A total of 64 Brangus calves were assigned to three treatments: hyper-early (W30), weaned at 32±0.89 days of age (n = 22, 10 males and 12 females); early (W75), weaned at 77±0.95 days of age (n = 20, 12 males and eight females); and conventional (W180), weaned at 183±0.82 days of age (n = 22, 13 males and nine females). Body weight (BW), average daily gain (ADG), β-hydroxybutyrate (βHBA), and morphometric measurements were evaluated. These variables were influenced by an interaction between treatment and days and were not affected by the sex of calves. The W30 calves experienced weight loss from 30 to 40 days of age compared with the W75 and W180 calves. Consequently, at day 75, W30 animals were lighter and had lower body length, thoracic circumference, withers height, and croup height compared with the W75 and W180 calves. However, no significant differences in BW were observed among treatments at 85 days of age. Additionally, W30 calves exhibited higher ADG and a moderate correlation with βHBA levels. Weaning calves at 30 days of age may negatively affect their performance until the sixth week after weaning, but there is no impairment in performance at 190 days of age.

Resumo em Inglês:

ABSTRACT The relationship between animal products and agricultural gross domestic product (AGDP) in Türkiye was investigated in this study. We used data of eight animal products (cow milk, sheep milk, beef, mutton, poultry meat, eggs, wool, and honey) from 1980 to 2020. After checking the stationarity of the series by the Augmented Dickey-Fuller (ADF) test, the Johansen cointegration test was used to establish the existence of a long-term relationship between animal products and AGDP, and the results were interpreted using The Fully Modified Ordinary Least Squares (FMOLS) analysis. According to the findings, honey, beef, poultry meat, mutton, eggs, and wool had a positive and significant relationship with AGDP in Türkiye, whereas sheep milk and cow milk and AGDP was not significant. The total effect of the examined animal products on AGDP was 0.61%. The results showed that wool was the most important contributor to AGDP among the products analyzed. Therefore, it is suggested that policymakers develop funding strategies to expand the production of these products.

Resumo em Inglês:

ABSTRACT This study aimed to analyze the economic viability of the implementation of a mechanized harvesting of broilers where the activity is carried out entirely manually. The viability indicators used were net present value (NPV), net future value (NFV), net uniform value (NUV), discounted payback (DP), and internal rate of return (IRR). Scenario analysis, sensitivity, and Monte Carlo simulation were performed in the present study. The results showed that the initial investment was US$ 1,868,302.76. The average price paid by the slaughterhouse to third-party manual harvesting companies was US$ 18.17 per thousand broilers, which was converted into revenue in the cash flow of the project. The cash flow result was positive at US$ 22,256.14 over the entire study period considering a daily catch of 144 thousand broilers. The results of the economic viability analysis were NPV of US$ 64,786.23, NFV of US$ 333,382.11, NUV of US$ 735.19, DP of 13.82 years, IRR of 0.965 monthly, and modified IRR of 0.933 monthly. These values prove the economic viability of implementing the project considering the market conditions at the time of the study. The analysis of scenarios showed great sensitivity to the exchange rate and the price of fuels. The Monte Carlo simulation highlighted a moderate risk of negative NPV, emphasizing the importance of considering this variable when making decisions. Despite these challenges, the potential benefits of mechanized harvesting, such as increased efficiency and reduced labor costs, make it a promising alternative to manual harvesting, even for small to medium-sized poultry industries.

Resumo em Inglês:

ABSTRACT This study aimed to assess the antimicrobial susceptibility of 52 Staphylococcus aureus (S. aureus) bovine mastitis isolates obtained from 37 dairy herds from the northwest of Portugal against antibiotics belonging to the β-lactam family, evaluate the detection of blaZ and mecA resistance genes, and study the diversity of positive isolates. The antimicrobial susceptibility tests were performed by the disk diffusion method. The detection of blaZ and mecA genes was performed using specific polymerase chain reaction (PCR) and the diversity of blaZ was evaluated by phylogenetic analysis. The antimicrobial susceptibility test showed a prevalence of phenotypic resistance by S. aureus of 52.0% against penicillin and ampicillin, 34.6% against oxacillin, 17.3% against amoxicillin plus clavulanic acid, and 21.1% against cefazolin. A prevalence of phenotypic intermediate resistance of 5.7% against penicillin, 9.6% against amoxicillin plus clavulanic acid, and 1.9% against ampicillin and cefazolin, respectively, was demonstrated. A 100.0% phenotypic susceptibility was found against piperacillin. Of the 52 S. aureus isolates, 35 (67.3%) were PCR positive for blaZ gene, and isolate 25 was positive for mecA gene. The phylogenetic analysis of partial blaZ gene S. aureus isolates consensus sequences were placed in two different clades, clade A (cluster A, A.1) and B (cluster B), all closely related to animal and/or human S. aureus strains. Isolate 2 appeared in the phylogenetic tree as the most divergent. This study indicates that blaZ resistance gene plays a role in β-lactam resistance in the tested bovine mastitis S. aureus isolates within dairy herds in the northwest of Portugal, especially in case of penicillin and ampicillin antibiotics that have shown a high phenotypic prevalence. Indeed, the proportion of bovine mastitis isolates with phenotypic resistance did not agree with the proportion of those identified for blaZ, as isolates with 100.0% of phenotypic susceptibility for all tested antibiotics also harbored blaZ. BlaZ phylogenetic analysis from S. aureus isolates showed diversity inside or between different herds in the northwest of Portugal. Piperacillin, as a suggestion, could be tested for S. aureus bovine mastitis treatment in the future to evaluate this new possibility of therapy.

Resumo em Inglês:

ABSTRACT Data from 83,088 Hereford and Braford cattle were used to compare parameters and breeding values obtained using linear and threshold models for visual scores of limb conformation (LCW and LCY), breed traits (BTW and BTY), sexual traits (STW and STY), eye pigmentation (EPW and EPY), and navel size (NSW and NSY) at weaning and yearling, respectively. Additionally, principal component analysis was applied to investigate the relationship among the estimated breeding values. Higher direct heritability were estimated using the threshold model (ranging from 0.134±0.021 to 0.194±0.023) compared with the linear model (ranging from 0.085±0.008 to 0.120±0.009). Rank correlations between breeding values predicted using linear and threshold models ranged from 0.61 to 0.88 (LCW), 0.53 to 0.91 (BTW), 0.66 to 0.87 (STW), 0.80 to 0.96 (EPW), 0.87 to 0.95 (NSW), 0.70 to 0.92 (LCY), 0.49 to 0.93 (BTY), 0.56 to 0.95 (STY), 0.88 to 0.97 (EPY), and 0.80 to 0.95 (NSY). The low genetic variability of the studied traits suggests a small genetic gain in the morphology and adaptation. According to the results obtained in the rank correlation, the percentage of coincident animals and the cross-validation analyses, it is recommended to use the threshold model for limb conformation, breed, and sexual traits. For eye pigmentation and navel size scores, both models can be used. In practical terms, the producer will be able to carry out his own selection, considering other traits that are not currently incorporated in the selection indexes, but that can lead to simultaneous gains in the morphology and adaptation of Hereford and Braford cattle.

Resumo em Inglês:

ABSTRACT The objective of this study was to estimate the genetic parameters and predict selection of genetic gains and genetic diversity of 12 Andropogon lateralis ecotypes collected in the State of Rio Grande do Sul, Brazil. To estimate genetic parameters and predict selection gains, the REML/BLUP technique was applied. Genetic diversity among the ecotypes was evaluated by two clustering methods (optimization and hierarchical) and principal component (PC) analysis, the latter method also used to discard variables. The genetic parameters studied showed high potential for selection of important agronomic forage traits for livestock production. Results showed that the 12 A. lateralis Nees ecotypes exhibited high genetic variability for the studied forage characters and indicated parental prosperity for crosses within the genetic breeding program. Principal component analysis showed that number of total vegetative tillers, leaf:stem ratio, number of reproductive tillers, and leaf dry matter yield accounted for 80.6% of the observed variation in PC1. These variables are important characteristics for quantifying the dry matter production and nutritional value of forage plants, and they can help to discriminate amongst ecotypes. Ecotypes sourced from the Pelotas, Piratini, Passo Fundo, Bagé, and Montenegro regions showed superior forage production when evaluated by the BLUP methodology. Therefore, this group was identified as the most suitable for selection and crossing purposes. Tocher’s cluster analysis grouped the ecotypes into five divergent groups. Principal component and UPGMA hierarchical methods were also efficient at separating the ecotypes.

Resumo em Inglês:

ABSTRACT This study was conducted to identify the key volatile compounds that characterize whether silage has deteriorated and to investigate the intrinsic link between the key compounds and silage odor. First, silages with different aerobic exposure durations were sampled, and sensory evaluation integrating aerobic stability monitoring was used to distinguish whether the silage had deteriorated. Subsequently, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) was utilized to determine the relative content of the compounds. Using the relative content of the compounds in each silage as input, relative odor activity value (ROAV) calculations and orthogonal partial least squares discriminant analysis (OPLS-DA) were performed to determine the odor contribution of the compounds and the compounds with significant differences in relative content (based on variable importance for the projection, VIP) between the deteriorated and non-deteriorated silages. Next, the key compounds were identified by combining the conditions of average ROAV (aROAV) ≥ 1 and VIP > 1. Finally, the OPLS algorithm was used to analyze the intrinsic link of key compounds with the silage odor. The results showed that three out of 63 compounds—4-ethyl phenol, eugenol, and ethyl linoleate—were key compounds to characterize whether the silages deteriorated or not. In addition, ortho-guaiacol, 4-ethyl guaiacol, and 2-methoxy-4-vinyl phenol were the specific key compounds for deteriorated silage. Eugenol and ethyl linoleate were correlated with fruity, sour, and spicy odors. In addition, guaiacol, 4-ethylphenol, 4-ethyl guaiacol and 2-methoxy-4-vinyl phenol contributed to roasted, musty, and putrid odors.

Resumo em Inglês:

ABSTRACT This study aimed to assess an alkaline protease supplemented in diets with and without crude protein (CP) reduction on performance, apparent total tract digestibility (ATTD), blood parameters, and carcass and meat traits in growing-finishing pigs. Forty male pigs (26.2±1.2 kg) were randomly allocated into one of five treatments: negative control (NC, 2% and 1% reduction of CP in grower and finisher phases, respectively, no protease); NC150: NC + 150 mg protease kg−1 diet; NC300: NC + 300 mg protease kg−1 diet; PC: positive control (no CP reduction and protease); and PC300: PC + 300 mg protease kg−1 diet, with eight replicates of one pig/pen. Pigs fed NC showed greater average daily feed intake (ADFI) than pigs fed NC300 or PC and lower ADFI compared to pigs fed NC150. Pigs fed PC had lower ADFI than those fed PC300. Greater average daily gain and gain to feed ratio (G:F) were observed in pigs on NC compared with those on NC300 or NC150 and NC300, respectively. Pigs fed PC showed better G:F than pigs fed PC300. Lower coefficients of ATTD (CTTAD) of dry and organic matter (OM), digestible dry matter (DDM), digestible organic matter (DOM), and digestible protein were observed in growing II pigs fed NC compared with pigs fed NC150 or NC300. Pigs fed NC showed a lower DP compared with PC or NC150. Positive control group showed increased digestible protein compared with NC. Finishing II pigs fed NC showed lower DDM, DOM, CTTAD of OM, and gross energy than pigs fed NC150 or NC300. Pigs fed PC showed greater albumin concentration compared with pigs fed PC300 in finishing II. Pigs fed NC and PC300 showed greater luminosity in the l. thoracis muscle than pigs fed PC. A greater color score was evidenced in the l. thoracis in pigs fed PC compared with pigs fed PC300. The dietary supplementation of isolated alkaline protease and CP-reduced diets improves ATTD without supporting pig performance.

Resumo em Inglês:

ABSTRACT A meta-analysis was employed to assess the effects of phytogenic feed additives and antibiotics on the performance and intestinal morphometry of unchallenged weanling pigs. The database included 41 articles published between 2004 and 2017, comprising 5,197 unchallenged nursery piglets. Piglets had 7.7 to 13.8 kg body weight and were assessed at 27.3 to 47.8 days of age, distributed into 156 experimental groups. All treatments were categorized into negative control, phytogenic additive (PA), and antibiotics (ATB) groups. The meta-analysis followed two sequential analyses: graphical and variance-covariance. Age and body weight were the factors that highly influenced the model. Piglets that received antibiotics had a higher (12.2%) daily weight gain than piglets in the control group. Phytogenic additives in diets enhanced intestinal morphometry in unchallenged piglets. Antibiotics increased (by 12.7%) the crypt depth of jejunum in comparison to the control treatment. Animals on PA had an 11.1% increment in villus height:crypt depth ratio than those on antibiotics. Phytogenic additives and antibiotics boost nursery piglet performance. Antibiotics advances the performance of unchallenged nursery piglets, but increases crypt depth in the jejunum. Performance of nursery piglets is better with combined phytogenic additives than with the isolated use of plant extracts.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the effects of prebiotics, alone and in combination with antibiotics, on broiler performance, carcass yield, intestinal permeability, and intestinal morphometry. A total of 1440 day-old male Cobb 500 chicks were distributed in a completely randomized design, with four treatments and 10 replications per treatment. The treatments used were a basal diet without prebiotics and antibiotics (BD), a basal diet with antibiotics (AB), a basal diet with prebiotics (PRE), and a basal diet with antibiotics and prebiotics (AB+PRE). To perform the treatment, the antibiotic zinc bacitracin and a prebiotic of S. cerevisiae-derived mannan-oligosaccharides and beta-glucans were used. The treatments did not affect the performance of birds from 1 to 7 and 1 to 21 days of age. From 1 to 35 and 1 to 42 days, birds fed the AB+PRE treatment had higher feed intake than those fed the AB treatment. From 1 to 35 days, birds fed the AB+PRE treatment showed a worse feed conversion ratio. However, there was no difference in carcass yield between treatments. A higher number of goblet cells was observed in the duodenum and ileum of birds fed AB+PRE, but lower counts were obtained in birds fed AB. Intestinal histomorphometry displayed similar responses between both ages regarding antibiotic and prebiotic treatments, except in the ileum at 42 days, in which the antibiotic elicited a better response. Intestinal permeability analysis showed no significant difference between diets. The use of prebiotics, alone or in combination with antibiotics, does not improve the performance of broilers.

Resumo em Inglês:

ABSTRACT This experiment was carried out to evaluate the effects of organic acids on the intestinal integrity and productive performance of broiler chickens experimentally inoculated with Salmonella Enteritidis. Additionally, Salmonella colonization levels in internal organs were evaluated. The study included 576 one-day-old CobbTM male broilers, distributed into eight treatment groups and six replicates. A completely randomized experimental design (encapsulated butyric acid × inoculation by Salmonella Enteritidis) was used. Poultry was orally inoculated with Salmonella Enteritidis in the first day (0 or 2.0 × 106 CFU/mL) and after 22 days of age (0 or 1.0 × 109 CFU/ mL). The butyric acid was added to the feed in different concentration (treatments 0.03, 0.075, and 0.15%), and the chickens were raised up to 42 days old. Encapsulated butyric acid at 0.03% increased the body weight gain and the average weight of the chickens up to 21 days old. After 14 days old, the butyric acid had a positive effect on jejunum villus. Encapsulated butyric acid at 0.03% in feed improves the performance and intestinal integrity of chickens.

Resumo em Inglês:

ABSTRACT This study aimed to investigate the effects of xylanase (Xyl) individually or in combination with B. subtilis and B. licheniformis associated or not with yeast cell wall in pig diets with a reduction of 100 kcal/kg of metabolizable energy (ME) content. Pig performance, bone parameters, intestinal morphometry, and bioeconomic indices were evaluated. A total of 75 pigs (25 females and 50 barrows; 25.02±3.21 kg) obtained from crossing Large White × Landrace were used. The experimental design consisted of randomized blocks, with five treatments and five blocks, totaling 25 experimental units subjected to treatments: basal diet (B); basal diet with reduction of 100 kcal/kg of ME (BEM); BEM with supplementation of xylanase (0.01%; BX); BX with supplementation of direct-fed microbials (composed of B. subtilis and B. licheniformis; 0.02%; BXM); and BX supplemented with 0.10% of symbiotic (which includes B. subtilis, B. licheniformis, and yeast cell wall; BXS). There were no differences in bone parameters. The BEM diet resulted in a lower villus height:crypt depth ratio in the jejunum than that seen upon using the BXS diet as feed. In the first period, pigs fed BEM diet had a 12% higher average daily feed intake than those fed the BXM diet. There were no differences in the pig performance during the second period. Over the total period, pigs fed BEM diet had greater FCR compared with pigs fed BXM diet. The inclusion of feed additives in diets with reduced ME content contributes to the maintenance of performance and characteristics of the metacarpus and jejunum of growing pigs and provides better bioeconomic indices.

Resumo em Inglês:

ABSTRACT In this study, a mixture of estradiol benzoate, progesterone, and testosterone propionate was injected into Diannan small-ear sows to induce estrus. The 16S rRNA technology was used to comparatively analyze the differences in fecal microbial composition and diversity between induced and spontaneous estrus in Diannan small-ear sows. The most abundant phylum in the sows in estrus were Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. There was a significant negative correlation between Firmicutes and Bacteroide and a significant positive correlation between Bacteroides and Bifidobacterium. The relative abundance of Stenotrophomonas, Neisseria, Anaerofustis, and Terrisporobacter in the sows during induced estrus was significantly higher than that during spontaneous estrus. Taken together, induced estrus affects the relative abundance of specific microbes in the feces of Diannan small-ear sows, but it does not affect the overall composition and diversity. These results provide fundamental knowledge about the gut microbiota of sows with induced estrus.

Resumo em Inglês:

ABSTRACT This study aimed to investigate the effects of different levels of vitamin D3 in broiler diets on performance and bone health. A total of 360 one-day old male Cobb500® broiler chicks were subjected to five treatments of different levels of vitamin D3 in diets during two rearing phases: 0 IU/kg in both phases; 625 IU/kg in starter and 500 IU/kg in grower phase (25% of commercial inclusion); 1,250 IU/kg in starter and 1,000 IU/kg in grower phase (50% of commercial inclusion); 1,875 IU/kg in starter and 1,500 IU/kg in grower phase (75% of commercial inclusion); and 2,500 IU/kg in starter and 2,000 IU/kg in grower phase (100% of commercial inclusion). The traits studied weekly were feed intake, body weight, feed conversion, and viability. At 21 and 35 days of age, tibiae and femurs were removed, dissected, and evaluated for dry matter (DM), ash (%MM), calcium (%Ca), phosphorus (%P) and breaking strength. At 35 days of age, the bones were subjected to histopathological analysis for macro- and microscopic morphological evaluation. Data were subjected to regression analysis, using α = 0.05. The variables of percentage %MM, %Ca, %P, and breaking strength experienced a positive linear effect up to the supplementation levels of approximately 25% of inclusion. The histopathological analysis found that the group that received the diet with 100% inclusion of vitamin D3 presented lesions compatible with osteopetrosis and tibial dyschondroplasia. The observed results showed that for isonutritive diets, reduced levels of vitamin D3 guaranteed performance during the evaluated period while the use of 100% of vitamin D3, as commonly used, can cause bone diseases and harm the welfare of broilers.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the performance of Nellore bulls finished in the feedlot and fed high-energy diets containing sodium monensin associated or not with tannins and saponins. Ninety-six Nellore bulls were used with an average initial body weight of 350.6±17.9 kg. The bulls were weight-blocked and randomly allocated to 12 pens, which were considered the experimental units. The treatments were assigned to the pens according to the blocks, as follows: sodium monensin (25 ppm; SM) and sodium monensin (25 ppm) plus tannins (350 ppm) and saponins (3.92 ppm, SM+TS). The bulls received an adaptation diet for the first 19 days, a growing diet from day 20 to day 59, and a finishing diet from day 60 to 98 of the experimental period. The animals were slaughtered after 98 days of study. The addition of tannins and saponins to the diets of feedlot Nellore cattle did not change the dry matter intake, hot carcass weight, and dressing percentage; however, it increased body weight by 2.0% and average daily gain by 5.4% and improved feed conversion by 4.3%. The addition of tannins and saponins to high-concentrate diets containing sodium monensin improves the productive performance of Nellore cattle finished in a feedlot for 98 days.