Improving nitrogen efficiency in dairy cattle requires a better understanding of the dietary and ruminal factors that regulate nitrogen partitioning. This meta-analysis evaluated the effects of ruminal pH and dietary characteristics on microbial nitrogen (MN), non-microbial non-ammonia nitrogen (NANMN), and NAN flows to the small intestine in lactating cows. A dataset was assembled from 44 peer-reviewed in vivo studies (163 data points), with dietary intake and ruminal variables standardized across trials. Mixed linear models were developed for each N fraction, and the relative contribution of each predictor to the explained variance was assessed using semipartial coefficients of determination (pR²). Efficiency of microbial protein synthesis (EMPS), rumen undegraded protein intake (RUPI), and organic matter truly digested in the rumen (OMTDR) were the most relevant predictors of NANMN and NAN. Although the ruminal pH itself was not statistically significant in the models, the dietary components that influenced pH, starch concentration, physically effective fiber, and RUP supply were strongly associated with nitrogen flow profiles. Nitrogen utilization was not affected by ruminal pH, but rather by the combination of fermentable substrates and the supply of rumen-degradable and undegraded protein.

The aim of this study was to characterize the feedlot system in the south and southeast of Pará state. Nine professionals completed the survey on an electronic survey consisting of 65 questions. Corn was the main source of grain used in finishing diets, most of the Flint type. Fine grinding and coarse grinding were the main grain processing methods adopted. The most adopted level of inclusion of concentrate and roughage was from 71 to 81% and from 20 to 40% respectively. More than 50% of respondents adopted an adaptation period of more than 14 days and an initial roughage level of diets from 35 to 50% of dry matter. Most cattle fed in the feedlots surveyed are Nellore intact males. Most animals were fed for up to 100 days and left the feedlot weighing more than 550 kg of BW. The finishing diets adopted in feedlots located in the south and southeast region of Pará state presented a lower level of inclusion of concentrated and higher inclusion of roughage than the national average. Processing methods that increase the digestibility of Flint-type corn starch are still rarely used. Nellore intact males are slaughtered heavier than the national average. The feedlot system in the south and southeast of Pará has accompanied the development of the beef industry in Brazil.

Objetivou-se avaliar a produtividade e os custos de produção de silagem de milho, em uma propriedade leiteira em Rio Maria – Pará. Para a análise de produtividade foram estimadas a Densidade Populacional de Plantas (DPP), Biomassa Total de Matéria Natural (BTMN) e Biomassa Total de Matéria Seca (BTMS), já os custos de produção da silagem produzida, foram estimados a partir dos custos fixos e variáveis envolvidos na atividade, e o custo de oportunidade da terra. A DPP estimada foi de 72.600,00 plantas/ha, a BTMN 63,40 toneladas/ha, e a BTMS foi de 19,90 toneladas/ha. A BTMN considerando 15% de perdas durante a ensilagem foi de 53,90 toneladas/ha. O custo total de produção foi de R$ 14.624,07/ha, e R$ 271,52/tonelada de silagem de milho, valor abaixo do comercializado na região. A maior parte dos custos operacionais concentrou-se no plantio R$ 6.495,00/ha, sendo os fertilizantes os insumos que mais contribuíram para o custo total de produção R$ 3.883,93/ha. A alta produtividade da lavoura de milho analisada nessa propriedade do estado do Pará sinaliza o potencial agrícola da região de Carajás.

Sleep in cattle is a complex physiological state comprising non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, while drowsing represents an intermediate vigilance state between wakefulness and sleep. Research has progressed from invasive electrophysiological recordings to noninvasive polysomnography (PSG), behavioral assessment, accelerometry, and automated classification approaches. However, accurately identifying and quantifying vigilance states under production conditions remains challenging. This narrative review, based on 22 primary studies identified through searches of Web of Science, Scopus and Google Scholar, critically synthesizes current knowledge of sleep physiology in cattle, the approaches used to assess it, and the principal methodological limitations affecting interpretation of the available evidence. Cattle exhibit a polyphasic sleep pattern, with NREM generally accounting for the largest proportion of total sleep. However, reported sleep and drowsing durations vary considerably among studies, and these differences may reflect both biological variation and methodological factors. Drowsing is particularly difficult to characterize because its behavioral and physiological features overlap with quiet wakefulness and light sleep. Rumination represents an additional challenge because associated muscular activity can interfere with electrophysiological recordings and complicate vigilance-state classification. Behavioral observations and accelerometry provide scalable measures of resting and sleep-like behavior but cannot independently establish physiological sleep, whereas PSG provides greater physiological resolution while remaining susceptible to artifacts and practical constraints. Current evidence is insufficient to establish causal relationships between sleep variation and cattle health, welfare, or productive performance. Future research should improve physiological classification during overlapping behavioral states, better validate scalable monitoring approaches, and evaluate the functional consequences of sleep variation across diverse cattle populations and production conditions.