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In recent years, machine learning (ML) algorithms have emerged as powerful tools for predicting and modeling complex data. Therefore, the aim of this study was to evaluate the prediction ability of different ML algorithms and a traditional empirical model to estimate the parameters of lactation curves. A total of 1186 monthly records from 156 sheep lactations were used. The model development process involved training and testing models using ML algorithms. In addition to these algorithms, lactation curves were also fitted using the Wood model. The goodness of fit was assessed using correlation coefficient (r), mean absolute error (MAE), root mean square error (RMSE), relative absolute error (RAE), and relative root mean square error (RRSE). SMOreg was the algorithm with the best estimates of the characteristics of the sheep lactation curve, with higher values of r compared to the Wood model (0.96 vs. 0.68) for the total milk yield. The results of the current study showed that ML algorithms are able to adequately predict the characteristics of the lactation curve, using a relatively small number of input data. Some ML algorithms provide an interpretable architecture, which is useful for decision-making at the farm level to maximize the use of available information.

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The objective of this study was to evaluate the effect of the silo type with the use or not of additives on chemical composition, in vitro gas production, fermentative losses, aerobic stability, fermentative profile, and microbial population of the pearl millet silage. We used a randomized block design in a 2 × 3 factorial scheme, with two types of silos (plastic bags and PVC silos) and three additives ([CON] without additive; 50 g of ground corn [GC], and Lactobacillus plantarum and Propionibacterium acidipropionici, with five replicates per treatment. We evaluated the chemical analyses, in vitro gas production, losses, aerobic stability, pH, ammoniacal nitrogen, and microbial population of the silages. The use of GC in the ensiling process improved the chemical composition of the silages. The additives and the type of silo did not affect (p > 0.05) the gas production kinetics, ammoniacal nitrogen, and population of lactic acid bacteria and fungi. Thus, the use of ground corn improved the nutritional value of the pearl millet silage. In turn, the inoculant provided better aerobic stability for the pearl millet silage. The plastic bag silos without vacuum were not efficient in the ensiling process like the PVC silos, which resulted in low-quality silage.

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This study aimed to empirically evaluate the adjustment quality of two stoichiometric models of methane production from diets that used different rumen fermentation modulators. We used the models proposed by Moss et al. (2000) and Blümmel et al. (1997). The data set consisted of 169 observations of in vitro methane production and volatile fatty acids (acetate, propionate, and butyrate) from dissertations, theses, and scientific articles. The model's adequacy evaluation was only possible through combination of several statistical analyzes. The models were unable to predict the enteric methane precisely and accurately. Despite this, the model proposed by Moss et al. (2000) showed a better fit based on the mean bias (% of observed, MB), MEF, RMSEP, Cb and CCC measures compared to the model proposed by Blümmel et al. (1997). However, both models presented strong evidence against the general hypothesis H0: a = 0 & b = 1. Thus, the model proposed by MOSS et al. (2000) was more efficient, whereas the model by Blümmel et al. (1997) showed a better fit for diets with high availability of H2.

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The objective of the present study was to evaluate the use of microbial inoculant on the chemical composition, in vitro gas production, pH, dry matter losses, aerobic stability and microbial population on silages of corn, sorghum and pearl millet in plastic bags silos (without vacuum). The experiment was carried out in a randomized block design, in a 2 × 3 factorial scheme, with and without (control) inoculant consisting of Lactobacillus plantarum and Propionibacterium acidipropionici and on three crops, corn, sorghum and pearl millet, with four replicates. The use of the inoculant did not affect the chemical composition of the silages, except the crude protein (P = 0.0062) and lignin (P = 0.0567) contents. Gas production was neither affected (P > 0.05) by the inoculant nor by the crop. Regarding aerobic stability, we observed that the inoculant affected the temperature of the sorghum silage (P = 0.0123). The inoculant decreased the N-NH3 (P =0.0095) content and increased (P = 0.0441) the lactic acid bacteria population in the silages. Thus, the microbial inoculant did not improve the fermentation profile or nutritional value of corn, pearl millet and sorghum silages in plastic bag silos (without vacuum).(AU)

O objetivo do presente estudo foi avaliar o uso de inoculante bacteriano na composição química, produção de gás in vitro, pH, perdas de matéria seca, estabilidade aeróbia e população microbiana de silagens de milho, sorgo e milheto em silos de sacos plásticos (sem vácuo). O experimento foi conduzido em delineamento de blocos casualizados, em esquema fatorial 2 × 3, [Controle] sem inoculante e Lactobacillus plantarum e Propionibacterium acidipropionici e três culturas, milho, sorgo e milheto, com quatro repetições. O uso do inoculante não afetou a composição química das silagens, exceto proteína bruta (P = 0,0062) e lignina (P = 0,0567). A produção de gás não foi afetada (P > 0,05) pelo inoculante e nem entre as culturas. Na estabilidade aeróbia, observou-se que o inoculante afetou a temperatura da silagem de sorgo (P = 0,0123). O inoculante diminuiu o conteúdo de N-NH3 (P = 0,0095). O inoculante aumentou (P = 0,0441) a população de bactérias ácido-láticas nas silagens. Assim, o inoculante microbiano não melhorou o perfil fermentativo e o valor nutricional das silagens de milho, sorgo e milheto em silos de sacos plásticos (sem vácuo).(AU)

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The study aimed to nutritionally evaluate the silage of pineapple crop waste in sheep feeding in different planes of nutrition (L). We used eight growing sheep and four male castrated adults, in individual metabolic cages distributed in a switchback design with two treatments and three periods. The treatments were the different planes of nutrition: L = MEI/Mm, MEI/1.5Mm, and MEI/2.5Mm, in which L = MEI/Mm, MEI is the energy amount of the feed intake and Mm is the maintenance. We performed a digestibility trial of the diet composed of silage of pineapple crop waste, ground corn, and soybean meal. Data were analyzed using regression analysis. Nutrient intake behaved linearly according to the increase in the L, except for organic matter, which presented a quadratic behavior. Planes of nutrition did not affect protein and fiber digestible fractions. However, digestible fractions of fat and non-fibrous carbohydrates (NFC) increased with L. The indigestible fractions displayed a quadratic behavior with an increase in the L. Regarding the microbial synthesis efficiency, we observed a linear decrease with the increase in L. Thus, the silage of pineapple crop waste is a feed very rich in NFC. Besides, silage of pineapple crop waste presented a good alternative roughage during forage shortages. Diet inclusion of 2.5x the maintenance does not compromise the sheep performance.(AU)

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The objective of this study was to nutritionally evaluate the use of pineapple crop waste silage in the feeding of growing bull in different planes of nutrition. We used eight non-castrated growing bull housed in individual covered pens, provided with free access to water and individual trough. Two balanced Latin squares conducted simultaneously were used. Treatments consisted of four planes of nutrition (L), formed by multiples of maintenance, i.e., L = ME/Mm; they were ME/Mm, ME/1.5Mm, ME/2Mm, and ME/2.7Mm. The intake of nutrients in diets was determined by the difference between the total mass of food offered and the mass of orts. To determine nutrient digestibility and nitrogen balance, total feces, and urine, collections were performed for seven consecutive days in each animal per period. The increase in planes of nutrition affected (P < 0.05) nutrient intake between L = 1 and L = 1.5. However, there was no effect nutrients intake to 1.5, 2, and 2.7. Nutrient digestibility was affected by the increase in planes of nutrition (P < 0.05), except for dCF (P = 0.0659). Digestible and metabolizable energies were affected (P < 0.05) by the increase in nutritional plans, as well as nitrogen balance. In conclusion, the pineapple crop waste silage presents itself as a good forage alternative for cattle diets, especially during forage shortage periods. Inclusion in the diet at 2.7 × the maintenance level does not compromise growing bull performance. However, the increases in planes of nutrition reduce the digestible energy contents of the diet.

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The use of supplements eliminates deficiencies imposed by pasture, increases weight gain in animals and maximizes profits from the activity. The objective of this study was to evaluate the performance, carcass traits and meat quality of steers in grazing systems that received or did not receive a protein energy supplement at the level of 0.6 % body weight. The experiment lasted 160 days and included 36 Brangus × Zebu animals. Eighteen animals received supplementation and another eighteen did not receive supplementation. Carcasses were evaluated for yield, loin eye area, fat thickness and length. The assessment of meat quality evaluated the shear force, myofibril fragmentation index, color, exudative losses and collagen. The carcass traits of the supplemented animals showed higher values (p < 0.0001). Supplementation improved the color of the meat (p = 0.0434) and increased the amount of soluble collagen (p = 0.0456). The use of a protein energy supplement for steers in a pasture system increased the efficiency of muscle deposition of these animals and improved meat quality when compared to animals that were not supplemented.(AU)

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The use of supplements eliminates deficiencies imposed by pasture, increases weight gain in animals and maximizes profits from the activity. The objective of this study was to evaluate the performance, carcass traits and meat quality of steers in grazing systems that received or did not receive a protein energy supplement at the level of 0.6 % body weight. The experiment lasted 160 days and included 36 Brangus × Zebu animals. Eighteen animals received supplementation and another eighteen did not receive supplementation. Carcasses were evaluated for yield, loin eye area, fat thickness and length. The assessment of meat quality evaluated the shear force, myofibril fragmentation index, color, exudative losses and collagen. The carcass traits of the supplemented animals showed higher values (p < 0.0001). Supplementation improved the color of the meat (p = 0.0434) and increased the amount of soluble collagen (p = 0.0456). The use of a protein energy supplement for steers in a pasture system increased the efficiency of muscle deposition of these animals and improved meat quality when compared to animals that were not supplemented.

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The objective of this study was to evaluate the morphogenetic traits and chemical composition of Tanzania grass using a fixed rest period or according to light interception at 95%. The treatments consisted of evaluations of two Tanzania-grass pasture-management strategies: (1) LI95 - animals entered the paddocks when the pasture reached 95% of light interception (LI), with three days of paddock occupation; and (2) FR - the pasture was managed with a defoliation interval (DI) of 30 days, and three days of paddock occupation. The experimental area consisted of 4 ha, with 22 paddocks per treatments. Ten recently-calved cows were used per treatment in year 1, and eight cows were used per treatment in year 2. Sward height, forage mass, and morphological components and their chemical composition were evaluated. The management strategies used on the Tanzania grass pasture did not affect pasture mass or height in the pre- and post-grazing conditions, or the proportion of stems. However, the proportion of leaves was greater in the paddocks with 95% light interception. The crude protein content was higher in the paddocks with 95% light interception; the other nutrients were not affected. In conclusion, management adopting 95% light interception does not influence morphogenetic traits. Nevertheless, it promotes an increase in the crude protein content of grasses.

O objetivo deste trabalho foi avaliar as características morfogênicas e a composição química do capim-tanzânia, utilizando um período de descanso fixo ou de acordo com a interceptação luminosa a 95%. Os tratamentos consistiram de avaliações de duas estratégias de manejo de pastagem de capim Tanzânia: (1) LI95 - animais entraram nos piquetes quando o pasto atingiu 95% de interceptação luminosa (LI), com três dias de ocupação do piquete; e (2) FR - a pastagem foi manejada com um intervalo de desfolhamento (DI) de 30 dias e três dias de ocupação do piquete. A área experimental consistiu de 4 ha, com 22 piquetes por tratamento. Dez vacas recém-paridas foram utilizadas por tratamento no ano 1, e oito vacas foram utilizadas por tratamento no ano 2. A altura do pasto, a massa de forragem e os componentes morfológicos e sua composição química foram avaliados. As estratégias de manejo utilizadas na pastagem de capim-Tanzânia não afetaram a massa ou a altura do pasto nas condições pré e pós-pastejo, ou a proporção de hastes. No entanto, a proporção de folhas foi maior nos piquetes com 95% de interceptação de luz. O teor de proteína bruta foi maior nos piquetes com 95% de interceptação de luz; os outros nutrientes não foram afetados. Em conclusão, o manejo adotando 95% de interceptação de luz não influencia as características morfogenéticas. No entanto, promove um aumento no teor de proteína bruta das gramíneas

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The objective of this study was to evaluate nutrient intake and digestibility, yield and components of milk from Holstein × Zebu cows on Tanzania grass pastures using a fixed-rest period or 95% light interception. The treatments consisted of evaluations of two Tanzania-grass pasture-management strategies: LI95 - when the pasture reached 95% light interception (LI), with 3 paddock-occupation days; and FR - the pasture was managed with a 30-days defoliation interval (DI) and 3 paddock-occupation days. Ten recently calved cows per treatment in year 1 and eight cows per treatment in year 2 were used, i.e. five cows per replicate in year 2 and four cows per replicate in year 2. Intake and digestibility of pasture nutrients, milk yield and milk composition were evaluated. The management strategies imposed on the Tanzania-grass pasture did not affect nutrient intake or digestibility. Milk yield and milk components were not affected by the management strategies, but milk yield per area unit was affected by the use of 95% light interception. The management strategy applying 95% light interception implies greater efficiency in the use of area, which translates to a higher milk yield per unit area, and thus it can be recommended to increase milk yield per area.

O objetivo deste estudo foi avaliar a ingestão e digestibilidade dos nutrientes, produção e os componentes do leite de vacas Holandesas × Zebu em pastagens de capim-Tanzânia em repouso fixo ou 95% de interceptação de luz. Os tratamentos consistiram de avaliações de duas estratégias de manejo de pastagem de capim Tanzânia: LI95 - quando a pastagem atingiu 95% de interceptação luminosa (LI), com três dias de ocupação do piquete; e TF - a pastagem foi manejada com intervalo de 30 dias de desfolha (ID) e três dias de ocupação do piquete. Dez vacas recém-paridas foram utilizadas por tratamento no ano 1 e oito vacas por tratamento no ano 2. Consumo e digestibilidade dos nutrientes do pasto, produção de leite e leite composição foram avaliados. As estratégias de manejo aplicadas na pastagem de capim-tanzânia não afetaram o consumo ou a digestibilidade dos nutrientes. A produção de leite e os componentes do leite não foram afetados pelas estratégias de manejo, mas a produção de leite por unidade de área foi afetada pelo uso de 95% de interceptação de luz. O manejo adotando 95% de interceptação de luz implica maior eficiência no uso da área, o que significa maior rendimento de leite por unidade de área, e assim pode ser recomendado aumentar a produção de leite por área.

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