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The article presents a study that determined the energy and protein requirements for maintenance and weight gain of crossbred cattle.

The article discusses research for evaluation of feed intake and development of lactation and weight change curves for under grazing Holstein x zebu cows conducted at the Agricultural Research Company of Minas Gerais (EPAMIG) in Felixlândia, Minas Gerais in Brazil. Topics discussed include impact of heat stress and metabolic changes on milk production from the European cattle breeds, breeding Bos indicus females with a Holstein bull and link between feeding behavior and nature of food.

The objective of this study was to measure performance and carcass characteristics of grazing Nellore bulls fed with fibrolytic enzyme (Fibrozyme®-Alltech) or not within two different supplementation strategies during the finishing phase in the dry season at low latitude. Twenty-eight Nellore bulls (24 mo; BW = 442 ± 16 kg) were used in a randomized complete block design with treatments in a 2 × 2 factorial arrangement of two supplementation strategies (constant or increasing levels) and presence (1.5g/100 kg BW) or absence of the fibrolytic enzyme product. The supplement was provided at the level of 10 g/kg BW supplement/d throughout the experiment (constant), or at 4, 8, 12 and 16 g supplement/kg BW during successive 35-d periods, with a total average of 10 g/kg BW. The increasing supplementation may compensate for the reduction in pasture quality and quantity as the dry season progressed. The pasture was composed of Brachiaria brizantha cv. Marandu (7 ha), divided into 7 paddocks (each one with 1 ha). Electronic individual feeding troughs (Intergado®) allowed all treatments to be represented in each paddock. The supplements were provided daily and the supplement intake (SI) was measured daily. Three reference animals were slaughtered initially to estimate the hot carcass weight (HCW). The remaining animals were slaughtered in a commercial abattoir after 140 d. The supplement efficiency (SE; g carcass gain/g supplement consumed) was calculated. All data were analyzed using the MIXED procedure of SAS (alpha = 0.10) with paddock considered random and animal as the experimental unit. There was no interaction (P > 0.10) between factors for BW, HCW, dressing percentage (DP), ADG, and SE. Final BW and ADG were not affected by supplementation strategy or fibrolytic enzyme. Feeding fibrolytic enzyme increased HCW (332 vs 324 kg, P = 0.098), and dressing percentage (58.4% vs 57.4%; P = 0.078) and SE (0.134 vs 0.123; P = 0.066). There was an interaction (P < 0.10) between supplementation strategy and enzyme for SI; the SI was lower with increasing supplement and enzyme (9.58 g/kg BW; P = 0.045) compared to the other treatments (mean = 9.92 g/kg BW). In conclusion, under the conditions of this study, providing the same amount of supplement with different strategies during the finishing phase in pasture does not alter animal performance. The inclusion of fibrolytic enzyme increased HCW, DP and SE. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of the supplementation level during the growing and the finishing phase on the performance of Nellore bulls in pasture. Forty calves (172 ± 26 kg, 8 mo) were used in a randomized block designed study with a 2×2×2 factorial arrangement of treatments (2 supplementation levels in the cold, warm season and in the finishing phase). The growing phase comprises all the seasons of the year, so it was subdivided into cold (fall/winter) and warm (spring/summer) seasons. Thus, twenty animals were fed 1 g/kg BW per day (CP = 54%, TDN = 40%) and twenty animals were fed 5 g/kg BW per day (CP = 25%, TDN = 58%) during the cold season. Afterwards, in the warm season, the animals from each supplementation during the cold season were fed either mineral salt ad libitum or 5 g/kg BW. Then, in the finishing phase, the same animals of each supplementation strategies during the growing phase were fed with one of two levels of concentrate (15 or 20 g/kg BW per day, CP = 17% or 14%, TDN = 76 or 77%, respectively). At the end of the experiment (405 days) bulls were weighed and slaughtered. All parts of the body were weighed separately to quantify the empty body weight (EBW). All data (EBW, HCW, no-carcass components [NCC = blood, heart, lung, spleen, liver, kidney, gastrointestinal tract and KPH] and gut fill) were analyzed using the PROC MIXED of SAS with an alpha = 0.05. There were no interactions between supplementation levels during the phases (P > 0.05), so the factors were analyzed separated. The cold season supplementation did not affect any variables (P > 0.05). In the warm season, animals fed 5 g/kg BW had greater EBW (471 vs 425 kg, P < 0.01), HCW (303 vs 269 kg, P < 0.01) and NCC (168 vs 156 kg, P = 0.01) compared with animals fed mineral. On the finishing phase, animals fed 20 g/kg BW had greater EBW proportion (940 vs 923 g/kg BW, P < 0.01) and lower gut fill (30 vs 37 kg, P = 0.03) than those fed 15 g/kg BW. In conclusion, supplementation in the cold season does not influence the performance of finishing Nellore bulls in pasture. However, the greater level of supplementation in the warm season and in the finishing phase produce animals with greater BW. [ABSTRACT FROM AUTHOR]

Water is the most important nutrient in animal production. Brazil has the largest commercial cattle herd, where the environmental conditions and beef cattle breeds are distinct from those described in the literature and there is no equation to predict water demanded by beef cattle for Brazilian breeds. Our objective was to validate 6 current water intake (WI) equations for beef cattle using water intake data from three experiments conducted in Southeastern Brazil (Nellore beef cattle). Animal performance, diet composition, and environmental data were collected for all experiments. The prediction of WI using the current published WI equations was tested though the regression between predicted and measured WI values. All tested equations did not agree with the measured WI data from the experiments. WI was overestimated by the previously published WI equations when compared to the actual WI observed in Nellore cattle raised in tropical conditions. Several factors can help to explain why the published equations did not predict the actual WI from the 3 experiments. The tested equations were developed in temperate climates using predominantly Bos taurus taurus. From the current data we generated new WI equations based on metabolic body weight (BW0.75), dry matter intake (DMI), humidity (HU) and temperature-humidity index (THI) for Nellore cattle in Southeastern Brazil, as follow: - 4.315 + 0.205 × BW0.75 - 0.17 × HU + 0.913 × DMI + 0.247 × THI. We recommended the proposed equation to estimate WI by Nellore cattle in tropical conditions. [ABSTRACT FROM AUTHOR]

An advantage of the Brazilian system is the predominant use of animals in pastures, so finishing Nellore in pasture with supplementation can be a strategy in Brazil to obtain meat quality. The objective of this study was to evaluate the effect of different nutritional strategies on meat quality and fatty acids profile of Nellore bulls fed in pasture. Twenty-four Nellore bulls (409 ± 18 kg and 25 mo) were used in a randomized block designed study. The treatments were: mineral-salt (100 g/animal per d during 155 d; MS), supplementation in the amount of 7 g/kg of BW per d (during 155 d; 7g/kg BW) or supplementation in the amount of 20 g/kg of BW per d (70 d fed mineral salt and 85 d fed 20g/kg BW; 20 g/kg BW). These treatments were done to evaluate if the intensity of the supplementation can affect the meat quality of finishing Nellore in pasture. The supplements were fed daily to paddocks (4 paddocks/treatment; 2 animals/paddock). The bulls were harvested on d 155. After 24-h chill, 2 steaks were taken from the longissimus dorsi (12th rib). All data were analyzed using the MIXED procedure of SAS with an alpha = 0.10. There were no differences in pH (5.98 ± 0.11) and cooking loss (31.7 ± 2.21). There was no difference (P > 0.20) on meat color (L* = 36.9 ± 1.12, a* = 16.9 ± 1.07, and b* = 14.1 ± 0.89) due to supplementation strategy. The shear force was similar (P = 0.59) among treatments (3.89 ± 0.51 kgf/cm2). Saturated and unsaturated fatty acids were similar (P > 0.14) among treatments. Bulls supplemented had greater monounsaturated fatty acids (P = 0.05). However, polyunsaturated fatty acids were similar (P = 0.65) among treatments. Bulls fed MS had greater (P = 0.07) omega-3 compared to bulls fed 20 g/kg (1.41 vs. 0.598). Bulls fed MS and 7 g/kg BW had similar omega-3. Delta 9 desaturase 18 was improved (P = 0.05) by 7.7% for bulls supplemented compared to MS. In conclusion, these data suggest that supplementation did not influence on meat quality. However, supplementation influence on fatty acids profile, so meat of bulls fed MS and 7 g/kg BW had greater omega-3 compared to animals fed 20 g/kg BW. [ABSTRACT FROM AUTHOR]

In Brazil, heifers typically calve at 36-48 months. Due to the high demand for meat and the need to reduce slaughter age, high supplementation has become commonly used in beef cattle farming. However, the literature remains scarce on studies that explore the impact of grazing management during the background phase on the productivity and reproductive efficiency of young Nellore heifers. This study aimed to evaluate the effects of two-herbage allowances (HA) on forage characteristics, performance, physiology and reproductive parameters of replacement Nellore heifers. Ninety weaned heifers [169 ± 19 kg of shrunk body weight (SBW); 210 ± 28 days of age] were blocked by initial BW and randomly assigned to receive different HA: (1) High herbage allowance (HHA: 7.2 kg DM/kg BW) and (2) Low herbage allowance (LHA: 3.3 kg DM/kg BW); and divided into six paddocks, totaling 12 paddocks. The experimental period was divided into the growing phase (D173) and the reproductive season (D83). Continuous stocking with a variable stocking rate was used. The supplement was provided daily with expected intake of around 10 g/kg of BW. The HHA pasture showed greater values of canopy height, greater HA, and lower values of CP and CP: in vitro digestible DM ratio than the LHA pasture over the days of the study (P ≤ 0.05). Herbage mass and the green stem proportion were lower in LHA pasture (P < 0.01), while the green leaf (g/kg DM) and senescent stem proportions (g/kg DM) were higher (P = 0.080) when compared to HHA pasture. Heifers maintained on HHA pasture had a higher average daily gain (P < 0.01), forage intake (P < 0.003), higher SBW (P < 0.01), Longissimus area (P < 0.01), and 12th-rib fat thickness (P < 0.01) than those kept in the LHA pasture. The proportion of heifers that reached the weight at maturity on D173 (P = 0.027) and the proportion of pubertal pregnancy heifers (P = 0.042) were greatest in the HHA treatment. The blood urea nitrogen (P = 0.002) was higher in heifers maintained in the LHA pasture. Heifers maintained in HHA pasture showed higher values of relative abundance of mRNA for UGT1A6 (P = 0.004) and IGFBP3 (P = 0.072). The use of HHA criteria increased forage intake, body gain, and carcass attributes of animals, which led to better reproductive performance of Nellore heifers., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Mycotoxins are present in almost all feedstuffs used in animal nutrition but are often ignored in beef cattle systems, even though they can affect animal performance. The objective of this study was to evaluate the effects of mycotoxins and a mycotoxin adsorbent (ADS) on performance of Nellore cattle finished in a feedlot. One hundred Nellore cattle (430 ± 13 kg) were used in a randomized complete block design with a 2 × 2 factorial arrangement of treatments. The factors consisted of two diets with either natural contamination (NC) or exogenous contamination (EC) and the presence (1 g/kg of DM; ADS) or absence of a mycotoxin adsorbent. The NC and EC diets had the following contaminations, respectively: 0.00 and 10.0 µg/kg aflatoxins, 5114 and 5754 µg/kg fumonisins, 0.00 and 42.1 µg/kg trichothecenes B, 0.00 and 22.1 µg/kg trichothecenes A and 42.9 and 42.9 µg/kg fusaric acid. At the beginning of the experiment, all animals were weighed, and four randomly selected animals were slaughtered to evaluate the initial carcass weight. After 97 days of treatment, all animals were weighed and slaughtered. There was no interaction among factors for the DM intake (DMI; P = 0.92); however, there was a tendency for the EC diets to decrease the DMI by 650 g/day compared to animals fed NC diets (P = 0.09). There was a trend for interaction among factors (P = 0.08) for the average daily gain (ADG), where the greatest ADG was observed for cattle fed the NC diet (1.77 kg), and the lowest was observed for those fed the EC diet (1.51 kg). The NC + ADS and EC + ADS treatments presented intermediate values for ADG. The animals fed the NC diet had a greater final BW (596 kg) than animals fed the EC treatment (582 kg; P = 0.04). There was a tendency for interaction among factors for carcass gain (P = 0.08). Similarly to ADG, the highest carcass gain was observed for animals fed the NC diet (1.20 kg), and the lowest was observed for those fed the EC diet (1.05 kg). The NC + ADS and EC + ADS treatments presented intermediate values. The natural contamination groups had greater carcass gain than that of the EC groups, and the use of the ADS recovered part of the weight gain in animals fed the EC diet. In conclusion, mycotoxins at the levels evaluated affected the performance of beef cattle, and adsorbents may mitigate their impact.

Ninety-six Nellore bulls (430 ± 13 kg and 24 months) were assigned to a completely randomized block design (2 × 2 factorial arrangement of treatments) to evaluate meat quality. Dietary treatments consisted of natural or exogenous contamination with mycotoxins (Factor 1), with or without yeast cell wall adsorbent (10 g/animal/d; Factor 2). The diets were provided during 97 d. The meat chemical composition was unaffected (P ≥ .37) by the factors and the averages of variables were 74.2% moisture, 22.7% protein, 1.04% ether extract, and 2.10% ash. The L*, a*, b*, E*, C* (P ≥ .11), cooking loss (P ≥ .24) and Warner-Bratzler shear force (P ≥ .17) were also similar among factors. In conclusion, low mycotoxin contamination and yeast cell wall based adsorbent do not affect meat quality of Nellore bulls finished in feedlot., (Copyright © 2019. Published by Elsevier Ltd.)