Strategies to alleviate heat stress on performance and physiological parameters in feedlot-finished cattle under heat stress conditions. A systematic review-meta-analysis.

Strategies to alleviate heat stress on live performance - dry matter intake (DMI), average daily gain (ADG), and feed conversion efficiency (FCE) - and on physiological parameters - respiratory rate (RR) and panting score (PS) - of feedlot-finished cattle were evaluated by systematic review-meta-analysis. Using the PICO framework were identified 3813 records, with 31 publications and 6729 cattle being considered in the meta-analysis (MA). The comparison most reported was sun vs. shade (n = 24 publications), followed by shade vs. shade (area per animal and effectivity in reduce solar load) (n = 7 publications) and sun vs. sprinkling (n = 4 publications). Cattle with access to shade with total reduction in solar load improved ADG (p = 0.008) and FCE (p = 0.024), and reduced RR (p < 0.001) compared to unshaded animals. Cattle with access to shade with a height between 3 and 4 m increased ADG (p < 0.001), tended to improve FCE (p = 0.054), and reduced RR (p < 0.001) compared to unshaded animals. An area of shade from 2 to 4 m2/animal increased ADG (p = 0.002), and higher than 4 m2/animal reduced RR (p < 0.001) compared to unshaded animals. Animals that received sprinkling volume below 1 L/animal/min improved ADG (p = 0.008) compared to unshaded animals. Cattle with access to shade with a high area per animal improved DMI (p = 0.023) and ADG (p < 0.001) compared to animals with a low area. In univariate meta-regression, it was observed that the variables significantly (P < 0.05) influencing DMI were THI category; influencing ADG were cattle gender, THI category, and coat color; influencing FCE were cattle age and hemisphere; and influencing RR were country, THI category and climate. Performance and physiological parameters of feedlot-finished cattle under heat stress depend on animal and environmental characteristics.

Oral meloxicam given as an ancillary treatment at respiratory disease diagnosis was not associated with growth, clinical scores, or ultrasound scores in preweaned dairy calves.

Objective: To assess the efficacy of a single dose of oral meloxicam as an ancillary therapy to an antibiotic given at the time of respiratory disease identification on average daily gain (ADG), behavioral attitude, clinical respiratory, and lung ultrasound scores in preweaned dairy calves. Animals: 215 male and female Holstein, Jersey, and crossbred preweaned calves enrolled between 1 and 14 days of age at study enrollment on a single commercial dairy in the western US. Methods: The study took place from March 4, 2021, to November 21, 2021. In this double-blind placebo-controlled study, calves were given an antibiotic (1.1 mL of tulathromycin/kg, SC, once) and either a placebo (1 mg of lactose monohydrate/kg, in a gelatin capsule) or oral meloxicam (1 mg/kg) at the time of respiratory disease identification. Behavioral attitude, clinical respiratory, and lung ultrasound scores and ADG were assessed in preweaned dairy calves at different time points including the next health examination, 1 week later, or at weaning. Results: There was no association between treatment (placebo vs meloxicam) on ADG or respiratory disease status at weaning (P > .05). There was no effect of treatment on behavioral attitude, clinical respiratory, or lung ultrasound scores at the next health examination or 1 week later (P > .05). Clinical Relevance: The present study did not provide evidence that oral meloxicam given once is beneficial for growth, behavioral attitude, or clinical or lung ultrasound scores.

Energy supplements for beef heifers on cool season pastures: a database analysis / Uso de suplemento energético para novilhas de corte em pastagens de estação fria: análise de banco de dados

Pooled data analysis is an analytical method that combines results from multiple studies. This technique provides a more robust estimate of the effects of an investigation. We performed a database analysis from seventeen experiments developed at Federal University of Santa Maria, Rio Grande do Sul state, Brazil, between 1999 and 2017 to characterize individual performance per area and stocking rate with or without supplementation of replacement heifers grazing winter pastures. Data were separated into two groups: with and without energy supplement provision, and into five subgroups based on supplement levels. Heifers from both groups were maintained under similar forage biomass and leaf blade allowance. Statistical analyses were run on R software using a 'meta' package. Supplement supply increased average daily gain and gain of body condition scores by 11.1% and 20.0%, respectively. Supplement levels higher than 1.2% of body weight resulted in higher weight gain per area, with the stocking rate increasing with higher supplement levels.

Análise conjunta de dados é um método analítico que integra os resultados de muitos estudos. Essa técnica fornece uma estimativa mais robusta sobre os efeitos de uma investigação. Com o objetivo de caracterizar o desempenho individual, por área e a taxa de lotação com uso ou não de suplementos para novilhas de reposição mantidas em pastagem de inverno, foi realizada uma análise de banco de dados de dezessete experimentos conduzidos na Universidade Federal de Santa Maria (UFSM), RS, Brasil, entre 1999 e 2017. Os dados foram estratificados em dois grupos: com e sem suplemento energético e cinco subgrupos de acordo com o nível de suplemento. As novilhas de ambos os grupos foram mantidas em similar massa de forragem e oferta de lâminas foliares. As análises estatísticas foram executadas no software R, pacote 'meta'. O fornecimento de suplemento aumentou o ganho médio diário em 11.1% e em 20.0% o ganho no escore de condição corporal. Níveis de fornecimento maiores que 1.2% do peso corporal proporcionaram o maior ganho de peso por área e a taxa de lotação aumenta à medida que os níveis de suplemento aumentam.

Effects of different levels of nano-selenium on growth performance, antioxidant capacity, biochemical parameters, and selenium content in Landes geese

The objective of this study was to evaluate the effects of dietary supplementation with different levels of nano-selenium (NS) on growth performance, antioxidant activity, biochemical parameters, and selenium content in Landes geese. A total of 120 80-week-old healthy Landes geese (4.44±0.03 kg) were randomly assigned to three groups, each with four replicates of 10 birds. The control birds were fed a basal diet without further dietary supplementation (0.0 mg/kg of NS) and the two experimental groups were fed the basal diet supplemented with dietary NS at 0.2 or 0.4 mg/kg of feed. The results demonstrated that NS dietary supplementation had no significant effect on growth performance. Increased total superoxide dismutase activity in serum, breast muscle and liver, glutathione peroxidase level in serum and liver, and catalase in breast muscle and liver were observed for both NS supplemented groups. Additionally, reduced malondialdehyde in serum, breast muscle, and liver was detected in both NS-supplemented groups. Compared with the control, the birds fed diets supplemented with NS had lower concentrations of alanine aminotransferase, triglyceride, aspartate aminotransferase, and low-density lipoprotein cholesterol in serum, while high-density lipoprotein cholesterol was increased. Furthermore, increased selenium, especially in the liver, was found in groups with dietary supplementation of NS. These findings suggest the supplementation of NS in diets can improve antioxidant status, biochemical parameters, and tissue selenium content, although it has no significant effect on growth performance of Landes geese.

Effect of Dietary Level of Beet Pulp, with or without Molasses, on Health Status, Growth Performance, and Carcass and Digestive Tract Traits of Rabbits.

To evaluate the effect of dietary level of beet pulp, with or without molasses, on growth performance, a total of 470 28-day-old rabbits were used (614 ± 6 g). Animals were randomly allocated into five dietary treatment groups: Control, without beet pulp; BP20, and BP40 with 20 and 40% of beet pulp without molasses, respectively; and BPM20 and BPM40, with 20 and 40% of beet pulp with molasses, respectively. Daily feed intake (DFI) and average daily gain (ADG) were controlled at 28, 49, and 59 days of age. Carcass and digestive tract traits were also determined at 59 days of age. Mortality and morbidity were controlled daily. Mortality during the growing period was higher in BPM than in BP groups (+9.2%; p < 0.05). The higher the inclusion of beet pulp, the lower the DFI and ADG of animals (5.5 and 4.6% for every 20% inclusion, respectively; p < 0.001), as well as the dressing out percentage, the liver proportion, and the dissectible fat percentage of their carcasses. However, the best feed efficiency during the last 10 days was obtained with the BPM40 group. The higher the inclusion of beet pulp, the higher the weight of the empty gastrointestinal tract and cecum (+2.4 and +3.0 percentage points for every 20% inclusion, respectively; p < 0.001). In fact, a higher inclusion of beet pulp decreased the pH and dry matter and decreased the total volatile fatty acids content of cecum richer in acetic acid but poorer in propionic, isobutiric, isovaleric, and valeric acids. Stomach weight was lower, and the capric acid content in the cecum was higher in the BPM than in the BP group. The inclusion of beet pulp in the feed reduced the growth performance and carcass yield of growing rabbits, and an even higher incidence of digestive disorders was observed when beet pulp included molasses.

Effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia / Efeitos da salinidade e de dietas contendo ingredientes de origem vegetal ou de origem animal e vegetal no desempenho e na condição metabólica de juvenis de tilápia do Nilo

The purpose of this study was to evaluate the effects of salinity and plant-based diet or animal-plant combination diet on the performance and metabolic status of juvenile Nile tilapia (Oreochromis niloticus). The experimental design was completely randomized in a 4 × 2 factorial scheme with four replicates. The treatments were established by the combination of salinities of 0, 10, 20, and 30 g L-1 with an animal-plant combination diet (AP) or plant-based diet (P). The replicates were 60 L tanks with 12 fish per tank. Diets were provided for 32 days, and the fish were fed three times a day (8, 12, and 17 h) until apparent satiety. Daily feed intake (DFI) was measured, body weight (BW) was recorded at the beginning and end of the trial, and total length (TL) and standard length (SL) were measured at the end of the trial. Average daily gain (ADG), specific growth rate (SGR), feed conversion ratio (FCR), and survival rate were calculated. After the biometric measurements were made at the end of the trial, blood samples were collected to determine the plasma concentrations of total protein (TP), glucose, cholesterol, and triglycerides (TG). The fish were euthanized, and the hepatopancreas was collected and weighed; thereafter, the hepatosomatic index (HSI) was calculated. An interaction was detected between salinity and diet type for final BW, ADG, TL, and SL. These traits were not influenced by salinity when it was associated with the AP diet, but reduced linearly with salinity in the P diet. DFI and survival rate were independently affected by salinity: DFI reduced linearly with salinity levels and survival rate was higher at a salinity of 10 g L-1. HSI increased linearly with salinity levels and was lower in the P diet than in the AP diet. Salinity had a quadratic effect on plasma TP, and the maximum value for this metabolite (2.96 g dL-1) is attained at a salinity of 10.26 g L-1. There was an independent effect of diet on the plasma concentrations of cholesterol and TG, which were lower in the P diet than in the AP diet. The salinity of 10 g L-1 associated with diet composed of animal and plant ingredients led to a better performance, higher survival rate, and less stressful environmental conditions for juvenile Nile tilapia.(AU)

O objetivo deste estudo foi avaliar os efeitos da salinidade e de dietas compostas por ingredientes de origem vegetal, ou por ingredientes de origem animal e vegetal no desempenho e na condição metabólica de juvenis de tilápia do Nilo (Oreochromis niloticus). O delineamento foi inteiramente casualizado em esquema fatorial 4 × 2 com quatro repetições. Os tratamentos foram estabelecidos pela combinação das salinidades 0, 10, 20 e 30 g L-1 com dietas contendo apenas ingredientes de origem vegetal (V) ou ingredientes de origem animal e vegetal (AV). As repetições foram caixas de 60 L contendo 12 peixes por caixa. As dietas foram fornecidas durante 32 dias e os peixes foram alimentados três vezes ao dia (8, 12 e 17 h) até saciedade aparente. O consumo de ração foi mensurado diariamente (CRD), o peso corporal (PC) foi registrado no início e no final do experimento, e o comprimento total (CT) e comprimento padrão (CP) foram mensurados no final do experimento. O ganho médio diário (GMD), a taxa de crescimento específico (TCE), a conversão alimentar (CA) e a taxa de sobrevivência também foram calculadas. Após a obtenção das medidas biométricas ao final do experimento, amostras de sangue foram coletadas para determinar as concentrações plasmáticas de proteínas totais (PT), glicose, colesterol e triglicerídeos (TG). Posteriormente, os peixes foram eutanasiados e o hepatopâncreas foi coletado, pesado e o índice hepatossomático (IHS) foi calculado. Houve interação entre salinidade e tipo de dieta para PC final, GMD, CT e CP. Essas variáveis não foram influenciadas pela salinidade quando associada com a dieta AV, mas reduziram linearmente com a salinidade na dieta V. O CRD e a taxa de sobrevivência foram influenciados exclusivamente pela salinidade, onde o CRD reduziu linearmente com a salinidade, e a taxa de sobrevivência foi maior na salinidade de 10 g L-1. O IHS aumentou linearmente com a salinidade, e foi menor da dieta V comparado com a dieta AV. Houve efeito quadrático da salinidade na concentração plasmática de PT, em que o máximo valor para este metabólito (2.96 g dL-1) pode ser alcançado com a salinidade de 10.26 g L-1. As concentrações plasmáticas de colesterol e TG foram exclusivamente influenciadas pelo tipo de dieta, apresentando menores valores na dieta V comparados com a dieta AV. A salinidade de 10 g L-1 associada com dieta composta por ingredientes de origem animal e vegetal proporcionou melhor desempenho, maior taxa de sobrevivência e condições ambientais menos estressantes aos juvenis de tilápia do Nilo.(AU)

Nutritional quality of wet distillers’ grains co–ensiled with whole–plant maize and its feeding value for lambs

The high moisture content of wet distillers' grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers' grains (WPMS + DDGS), and whole–plant maize (WPM) co–ensiled with WDGS (WPM – WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rumen pH of the wethers as a result of diet differences were observed. Lambs consuming the WDGS–based diet had a lower average daily intake and average daily gain (p 0.05). In conclusion, co–ensiling WDGS with whole–plant maize provides the opportunity for the long–term storage and utilization of WDGS in lamb feeding.

Nutritional quality of wet distillers grains coensiled with wholeplant maize and its feeding value for lambs

ABSTRACT: The high moisture content of wet distillers grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The coensiling with wholeplant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers grains (WPMS + DDGS), and wholeplant maize (WPM) coensiled with WDGS (WPM WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p 0.05) compared to the WPMS + SOM and WPMWDGS diets. However, the rapidly fermentable fraction, as well as the progressively fermentable fraction of the diet dry matter, was not different (p > 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rumen pH of the wethers as a result of diet differences were observed. Lambs consuming the WDGSbased diet had a lower average daily intake and average daily gain (p 0.05) compared to lambs consuming the DDGS and WPMSbased diets. However, the feed conversion ratio was not affected by diet differences (p > 0.05). In conclusion, coensiling WDGS with wholeplant maize provides the opportunity for the longterm storage and utilization of WDGS in lamb feeding.

Nutritional quality of wet distillers' grains co-ensiled with whole-plant maize and its feeding value for lambs

The high moisture content of wet distillers' grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co­ensiling with whole­plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers' grains (WPMS + DDGS), and whole­plant maize (WPM) co­ensiled with WDGS (WPM ­ WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p < 0.05) compared to the WPMS + SOM and WPM­WDGS diets. However, the rapidly fermentable fraction, as well as the progressively fermentable fraction of the diet dry matter, was not different (p > 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rumen pH of the wethers as a result of diet differences were observed. Lambs consuming the WDGS­based diet had a lower average daily intake and average daily gain (p < 0.05) compared to lambs consuming the DDGS and WPMS­based diets. However, the feed conversion ratio was not affected by diet differences (p > 0.05). In conclusion, co­ensiling WDGS with whole­plant maize provides the opportunity for the long­term storage and utilization of WDGS in lamb feeding.

Growth performance and meat quality of feedlot steers fed diets with or without natural feed additive

The objective of this study was to evaluate the growth performance and meat quality of feedlot Aberdeen Angus steers fed high-concentrate diets with or without a natural feed additive composed of a mixture of yeasts and essential oils (EO). A completely randomized design with two diets (with or without natural feed additive) and 12 replicates was used. Twenty-four steers with initial shrunk body weight of 402.62±48.2 kg and average age of 18±2.0 months were used. Steers were fed ad libitum a diet containing 777.3 g of concentrate/kg dry matter (DM) and 222.7 g of corn silage/kg DM for 74 days. The mixture of yeast and EO was supplied at the rate of 10.0 and 0.117 g/animal/day, respectively. Average daily weight gain and feed efficiency in the adaptation period was greater in animals fed natural feed additive; however, there was no difference for the total experimental period. Dry matter intake, carcass weight, carcass yield, proportion of carcass bone, carcass muscle + fat:bone ratio, round thickness, and arm length were not altered by treatments. The inclusion of a natural feed additive in the diet increased the cooling loss (0.98 vs. 1.25%), proportion of carcass muscle (51.32 vs. 54.56%), carcass muscle:fat ratio (1.70 vs. 2.11%), leg length (68.79 vs. 70.71 cm), and arm perimeter (36.70 vs. 37.88 cm) and reduced the proportion of carcass fat (30.17 vs. 25.92%). Carcass length was greater in animals fed the diet with a natural feed additive. Meat color, texture, and marbling were not altered by treatments. The addition of natural feed additive to high concentrate diets does not alter the productive performance of feedlot Aberdeen Angus steers, although it can increase the proportion of lean meat of carcasses.(AU)

Enteric methane emissions by young Brahman bulls grazing tropical pastures at different rainfall seasons in the Peruvian jungle.

The aim of this research was to measure enteric methane (CH4) emissions by young Brahman bulls grazing tropical pastures at different rainfall seasons in the Peruvian jungle. Fourteen 1.5-year-old, young bulls (280 kg ± 18 kg BW) were grazed on tropical grasses and legumes dominated by German grass [Echinochloa polystachya (Kunth) Hitch.] and minor proportion of Torourco grass [Paspalum conjugatum (P.J. Bergius) Roxb] and Leguminous Calopo (Calopogonium mucunoides Desv.) and Kudzú [Pueraria phaseoloides (Roxb.) Benth]. Enteric CH4 emission was measured by the sulfur hexafluoride (SF6) tracer-gas technique. Organic matter intake (OMI) was determined from organic matter digestibility (OMD) using a fecal protein crude index and fecal output estimated by the dosage of external markers. There was a difference in OMD between seasons (68 and 66% for the dry and rainy seasons, respectively; P < 0.0001). The OMI (6.7 and 7.4 kg/day) and CH4 (178.7 and 298 g/day) were higher (P < 0.05) in the dry season than in the rainy season, respectively. The yield of CH4 was lower (P < 0.0001) during rainy season (7.1%) than at the dry season (10.6%). The CH4 emission (g/day) was correlated with OMD (%) (r = 0.74, P < 0.0001). Enteric CH4 emissions of young bulls grazing mixtures of tropical pastures were significantly lower in animals grazing on the rainy-season, expressed either through unit of absolute emission, intake or as percentage of the GEI. Likewise, OMD of consumed pasture was the most important factor determining CH4 emission.

Beef Cattle on Pasture Have Better Performance When Supplied With Water Trough Than Pond.

The behavior and performance of steers on pasture regarding water availability in troughs or in ponds were compared. Eight paddocks were randomly allocated to one treatment: POND (~30 m of diameter) or TROUGH (water trough, 120 cm diameter and 60 cm high and 500 L capacity). Eight groups of six beef steers were randomly assigned to one of the paddocks. The first 10 days were considered for animal habituation. Animals were individually weighed (days 0, 30, 60, and 90). Beginning in the day after each weighing on days 30 (Month 1), 60 (Month 2), and 90 (Month 3), behavior and animal distribution in the paddock were recorded by direct visual observation in three periods of 4 consecutive days. Water temperature and fecal and herbage DM were also recorded in these periods. Water intake was measured during 16 random days in the troughs. Data were analyzed using Generalized Linear Mixed Models, with treatment and period as fixed effects. TROUGH steers gained more weight (0.44 vs. 0.34 kg/day/animal; P ≤ 0.007) during the experiment and were heavier than the others at the end of the study (P ≤ 0.05). POND steers spent more time drinking water, but TROUGH steers increased the number of drinking events throughout the study (P ≤ 0.05), suggesting an adaptation for the new type of water source. Both treatments increased grazing time throughout the study, but not ruminating time (P ≤ 0.05). Walking time differed between treatments in all periods of behavior observation (P ≤ 0.05). Events of animal licking and ingesting salt of POND steers reduced throughout the study (P ≤ 0.05). The number of drinking events of TROUGH steers increased throughout the study, and drinking events were longer for POND steers than TROUGH steers (P ≤ 0.05). TROUGH steers spent more time on pasture on Month 2 (P ≤ 0.05). Period collection did not affect the water intake of TROUGH treatment (P > 0.05). This study demonstrates that water available in troughs rather than ponds for steers on pasture has positive effects on their weight gain and affects cattle behavior.

Effect of different blend levels of spineless cactus and Mombasa hay as roughage on intake, digestibility, ingestive behavior, and performance of lambs.

This study aimed to determine the best level of the blend of spineless cactus (Nopalea cochenillifera) and Mombasa (Panicum maximum) hay as roughage in the diet of lambs based on intake, digestibility, ingestive behavior, and lamb performance. Forty-eight uncastrated crossbred Santa Ines breed lambs with an average age of 4 months old and an average initial BW of 20.5 kg ± 2.8 kg were distributed in two experiments using a completely randomized design: experiment 1: 16 lambs (four treatments and four replicates) for in vivo digestibility trial in metabolic cage; experiment 2: 32 lambs (four treatments and eight replicates) in feedlot to determine intake, ingestive behavior, and performance. As the amount of cactus in the roughage increased, there was a linear reduction (P <0.001) on intake (g/day) of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), non-fibrous carbohydrates (NFC) digestibility, time spent ruminating, feeding efficiency of NDF (P = 0.0153), NDF rumination efficiency rate (P = 0.032), final BW, TWG, and ADG of lamb. However, there was a linear increase (P <0.001) on the intake of the NFC and TDN, digestibility coefficient of DM, CP, total carbohydrates (TC) and NDF gross energy, metabolizable energy, and time spent idling when spineless cactus increased in the roughage blend. The least amount of cactus in the roughage (112-637 g/kg DM) promoted higher intake of DM and CP, improving lamb performance. However, the blend up to 450-300 g/kg DM improved digestibility and energy production as well as it did not affect the feed efficiency.

Narasin inclusion for feedlot lambs fed a diet containing high amounts of ground flint corn

Narasin is an antibacterial agent that may change rumen fermentation. Two experiments were proposed to evaluate the efficiency of narasin inclusion for lambs fed a diet containing high amounts of ground flint corn. Thirty rumen-cannulated wethers were used to evaluate nutrient digestibility, nitrogen balance, and rumen metabolism (Exp. 1); and forty-five lambs were used to evaluate performance (Exp. 2) of animals fed with narasin for high flint corn diets. The experimental diets were: control or basal diet without additives (C); 25 mg of monensin kg-¹ of dry matter (DM) (M); and inclusion of 5 (N5), 10 (N10), and 15 (N15) mg of narasin kg-¹ of DM. The statistical analyses were performed using the MIXED procedure of SAS. Monensin increased DM digestibility compared to C (p = 0.01) and increasing doses of narasin linearly increased DM digestibility (p < 0.01). There was a quadratic effect (p = 0.10) for molar proportion of acetate peaking at N15. Monensin inclusion increased (p = 0.07) propionate compared to C; however, it did not differ from narasin. The increasing levels of narasin linearly decreased the total volatile fatty acids concentration in the rumen (p = 0.02). Monensin and C showed a similar performance. The increasing levels of narasin linearly increased (p <= 0.04) average daily gain and feed efficiency. Monensin and narasin changed rumen fermentation and improved overall nutrient digestibility. However, lambs that received narasin showed improved performance when compared with animals that received M.(AU)

Relationship among productive and economic variables of beef cattle in Brazil / Relações entre variáveis produtivas e econômicas de bovinocultura de corte no Brasil

The present study aimed to obtain, through statistical methods, the independent variables that influence the economic and productive results of Brazilian beef cattle. Economic and productive information was collected from 106 farms in Brazil. Data collection was performed by the Instituto de Métricas Agropecuárias (Inttegra). The variable selection method used was stepwise regression followed by polynomial regression analyses. The variable beef cattle economic result showed the positive effect of disbursement per head per month and average weight gain. An average daily gain of 520 g in live weight was obtained, and this variable was influenced especially by nutrition cost. The arroba production (arroba is a unit of weight corresponding to 15kg) was influenced by the linear effect of nutrition cost and stocking rate. The variable arroba production in pasture showed a linear and positive effect of average weight gain in pasture and stocking rate in pasture. For profit per arroba, the variables nutrition cost, disbursement with pasture, and average sale price had a linear effect. The independent variables that had the greatest influence on the response variables were stocking rate, average daily weight gain, and nutrition cost. Thus, increases in investment in nutrition and stocking rate should result in higher production rates and improvements in the profitability of this activity.(AU)

O presente trabalho teve como objetivo obter, por meio de métodos estatísticos, quais variáveis independentes influenciam as variáveis econômicas e produtivas na bovinocultura de corte brasileira. O banco de dados utilizado foi obtido por coleta de informações econômicas e produtivas em 106 fazendas no Brasil. O método de coleta de dados foi definido pelo Instituto de Métricas Agropecuárias (Inttegra). Foram realizadas análises de seleção de variáveis pelo método Stepwise, seguido por análises de regressão múltipla. A variável resultado econômico da bovinocultura de corte teve efeito positivo do desembolso mensal por cabeça e do ganho de peso médio diário. Para o ganho de peso médio diário foi obtido um valor médio de 520 gramas, e esta variável foi influenciada principalmente pelo custeio com nutrição. Para a produção de arroba foi obtido efeito linear do custeio com nutrição e da taxa de lotação. Para a variável produção de arroba a pasto foi obtido um efeito linear e positivo do ganho médio diário de peso no pasto e da taxa de lotação no pasto. Para o lucro por arroba, as variáveis custeio com nutrição, desembolso com pastagem e preço médio de venda tiveram efeito linear. As variáveis independentes que tiveram maior influência nas variáveis resposta foram a taxa de lotação, o ganho médio diário de peso e o custeio com nutrição. Assim, aumentos no investimento em nutrição e na taxa de lotação dos animais devem resultar em maiores índices de produção e em melhorias na rentabilidade da atividade.(AU)

Narasin inclusion for feedlot lambs fed a diet containing high amounts of ground flint corn

Narasin is an antibacterial agent that may change rumen fermentation. Two experiments were proposed to evaluate the efficiency of narasin inclusion for lambs fed a diet containing high amounts of ground flint corn. Thirty rumen-cannulated wethers were used to evaluate nutrient digestibility, nitrogen balance, and rumen metabolism (Exp. 1); and forty-five lambs were used to evaluate performance (Exp. 2) of animals fed with narasin for high flint corn diets. The experimental diets were: control or basal diet without additives (C); 25 mg of monensin kg-¹ of dry matter (DM) (M); and inclusion of 5 (N5), 10 (N10), and 15 (N15) mg of narasin kg-¹ of DM. The statistical analyses were performed using the MIXED procedure of SAS. Monensin increased DM digestibility compared to C (p = 0.01) and increasing doses of narasin linearly increased DM digestibility (p < 0.01). There was a quadratic effect (p = 0.10) for molar proportion of acetate peaking at N15. Monensin inclusion increased (p = 0.07) propionate compared to C; however, it did not differ from narasin. The increasing levels of narasin linearly decreased the total volatile fatty acids concentration in the rumen (p = 0.02). Monensin and C showed a similar performance. The increasing levels of narasin linearly increased (p <= 0.04) average daily gain and feed efficiency. Monensin and narasin changed rumen fermentation and improved overall nutrient digestibility. However, lambs that received narasin showed improved performance when compared with animals that received M.

Relationship among productive and economic variables of beef cattle in Brazil / Relações entre variáveis produtivas e econômicas de bovinocultura de corte no Brasil

ABSTRACT: The present study aimed to obtain, through statistical methods, the independent variables that influence the economic and productive results of Brazilian beef cattle. Economic and productive information was collected from 106 farms in Brazil. Data collection was performed by the Instituto de Métricas Agropecuárias (Inttegra). The variable selection method used was stepwise regression followed by polynomial regression analyses. The variable beef cattle economic result showed the positive effect of disbursement per head per month and average weight gain. An average daily gain of 520 g in live weight was obtained, and this variable was influenced especially by nutrition cost. The arroba production (arroba is a unit of weight corresponding to 15kg) was influenced by the linear effect of nutrition cost and stocking rate. The variable arroba production in pasture showed a linear and positive effect of average weight gain in pasture and stocking rate in pasture. For profit per arroba, the variables nutrition cost, disbursement with pasture, and average sale price had a linear effect. The independent variables that had the greatest influence on the response variables were stocking rate, average daily weight gain, and nutrition cost. Thus, increases in investment in nutrition and stocking rate should result in higher production rates and improvements in the profitability of this activity.

RESUMO: O presente trabalho teve como objetivo obter, por meio de métodos estatísticos, quais variáveis independentes influenciam as variáveis econômicas e produtivas na bovinocultura de corte brasileira. O banco de dados utilizado foi obtido por coleta de informações econômicas e produtivas em 106 fazendas no Brasil. O método de coleta de dados foi definido pelo Instituto de Métricas Agropecuárias (Inttegra). Foram realizadas análises de seleção de variáveis pelo método Stepwise, seguido por análises de regressão múltipla. A variável resultado econômico da bovinocultura de corte teve efeito positivo do desembolso mensal por cabeça e do ganho de peso médio diário. Para o ganho de peso médio diário foi obtido um valor médio de 520 gramas, e esta variável foi influenciada principalmente pelo custeio com nutrição. Para a produção de arroba foi obtido efeito linear do custeio com nutrição e da taxa de lotação. Para a variável produção de arroba a pasto foi obtido um efeito linear e positivo do ganho médio diário de peso no pasto e da taxa de lotação no pasto. Para o lucro por arroba, as variáveis custeio com nutrição, desembolso com pastagem e preço médio de venda tiveram efeito linear. As variáveis independentes que tiveram maior influência nas variáveis resposta foram a taxa de lotação, o ganho médio diário de peso e o custeio com nutrição. Assim, aumentos no investimento em nutrição e na taxa de lotação dos animais devem resultar em maiores índices de produção e em melhorias na rentabilidade da atividade.

Performance and maternal-offspring behavior of ewes fed protected fat from palm oil / Desempenho e comportamento materno-filial de ovelhas alimentadas com gordura protegida de óleo de palma

This study aimed to evaluate the performance and maternal-offspring behavior of ewes fed protected fat from palm oil. Forty multiparous ewes with an average age of three years were divided into two treatments, with or without protected fat supplementation (in concentrate). Every 15 days and at the time of lambing, weighing and body condition evaluation of sheep were performed, while lambs were evaluated at birth until weaning. Duration of post-weaning anestrus was obtained through the manifestation of estrus, detected by a vasectomized male. Data were submitted to analysis of variance. No difference was observed between supplementations for body weight, body condition score, and average daily gain during the gestation phase. Ewes fed protected fat had a superiority regarding the body score during the lactation phase. Lambs from ewes supplemented with protected fat were weaned faster, and ewes presented an early estrus. No difference was observed between treatments for maternal-offspring behavior. The use of fat during lactation showed improvement in productive (body condition score) and reproductive (shorter anestrus period) parameters. It also reduces the weaning age of lambs and does not alter maternal-offspring behavior.(AU)

O objetivo foi avaliar o desempenho e comportamento materno-filial de ovelhas alimentadas com gordura protegida de óleo de palma. Foram utilizadas 40 ovelhas multíparas com idade média de três anos divididas em dois tratamentos, com ou sem suplementação de gordura protegida (no concentrado). A cada 15 dias e no momento do parto, foram realizadas pesagens e avaliação da condição corporal das ovelhas, enquanto os cordeiros foram avaliados no nascimento até o desmame. A duração do anestro pós-desmame foi obtida através da manifestação do estro, detectada por macho vasectomizado. Os dados foram submetidos à análise de variância. Verificou-se que na fase de gestação não houve diferença entre as suplementações, para peso vivo, escore de condição corporal e ganho médio diário. Na fase de lactação observa-se superioridade das ovelhas que receberam gordura protegida, no escore corporal. Cordeiros filhos de ovelhas suplementadas com gordura protegida foram desmamados mais rápidos e as ovelhas apresentaram cio mais cedo. Não houve diferença entre os tratamentos para o comportamento materno-filial. O uso da gordura durante a lactação apresentou melhoras em parâmetros produtivo (escore de condição corporal) e reprodutivo (menor período de anestro). Além de reduzir a idade de desmama dos cordeiros e não alterar o comportamento materno-filial.(AU)

Performance and maternal-offspring behavior of ewes fed protected fat from palm oil / Desempenho e comportamento materno-filial de ovelhas alimentadas com gordura protegida de óleo de palma

This study aimed to evaluate the performance and maternal-offspring behavior of ewes fed protected fat from palm oil. Forty multiparous ewes with an average age of three years were divided into two treatments, with or without protected fat supplementation (in concentrate). Every 15 days and at the time of lambing, weighing and body condition evaluation of sheep were performed, while lambs were evaluated at birth until weaning. Duration of post-weaning anestrus was obtained through the manifestation of estrus, detected by a vasectomized male. Data were submitted to analysis of variance. No difference was observed between supplementations for body weight, body condition score, and average daily gain during the gestation phase. Ewes fed protected fat had a superiority regarding the body score during the lactation phase. Lambs from ewes supplemented with protected fat were weaned faster, and ewes presented an early estrus. No difference was observed between treatments for maternal-offspring behavior. The use of fat during lactation showed improvement in productive (body condition score) and reproductive (shorter anestrus period) parameters. It also reduces the weaning age of lambs and does not alter maternal-offspring behavior.

O objetivo foi avaliar o desempenho e comportamento materno-filial de ovelhas alimentadas com gordura protegida de óleo de palma. Foram utilizadas 40 ovelhas multíparas com idade média de três anos divididas em dois tratamentos, com ou sem suplementação de gordura protegida (no concentrado). A cada 15 dias e no momento do parto, foram realizadas pesagens e avaliação da condição corporal das ovelhas, enquanto os cordeiros foram avaliados no nascimento até o desmame. A duração do anestro pós-desmame foi obtida através da manifestação do estro, detectada por macho vasectomizado. Os dados foram submetidos à análise de variância. Verificou-se que na fase de gestação não houve diferença entre as suplementações, para peso vivo, escore de condição corporal e ganho médio diário. Na fase de lactação observa-se superioridade das ovelhas que receberam gordura protegida, no escore corporal. Cordeiros filhos de ovelhas suplementadas com gordura protegida foram desmamados mais rápidos e as ovelhas apresentaram cio mais cedo. Não houve diferença entre os tratamentos para o comportamento materno-filial. O uso da gordura durante a lactação apresentou melhoras em parâmetros produtivo (escore de condição corporal) e reprodutivo (menor período de anestro). Além de reduzir a idade de desmama dos cordeiros e não alterar o comportamento materno-filial.

Changes in body water and solids contents in native and crossbreed growing calves during winter and hot summer seasons of Egypt

The objective of this study is studying the effect of genetic crossing on body water and body solids in growing calves under winter or summer season in Egypt. Twenty calves including 10 native calves and 10 F1 calves (♀ Egyptian cow × ♂ Holstein) were used through two experiments. The first experiment was conducted during winter season on ten calves including 5 native and 5 F1 calves with average 5-6 months of age. The second experiment was conducted during summer season on another ten calves with the same age and body weight including 5 native calves and 5 F1 calves. Results showed that summer season induced significant decreases in live body weight (LBW) by 27.2 kg in native and by 32.9 kg in F1 through 3 months and F1 calves were better than native calves by 23.2 kg and 17.5 kg under winter and summer seasons, respectively. Total body water (TBW) as percentage of LBW values increased significantly and total body solids (TBS) as absolute values through three months decreased significantly by 6.9 kg in native calves and by 9.0 kg in F1 calves due to exposure calves to summer season. Daily gain (BG) and daily solids gain (SG) decreased significantly due to exposure calves to summer season and F1 calves were better than native calves in live BG as well as in SG. The best values in gain were in F1 calves under winter condition and the worsted values were in native calves under summer season.(AU)