Feedlot Conditions Research Articles

PSV-20 Supplementation of an electrolyte solution improves water intake in receiving beef cattle under commercial feedlot conditions

Abstract During transport to and receiving at feedlots, cattle are exposed to a variety of stressors, including changes in social structure due to separation and mixing of groups, handling, and a lack of access to feed and water for extended periods of time. These stressors often result in loss of body mass and dehydration, which if not adequately addressed upon feedlot arrival, may result in increased morbidity and mortality. The objectives of this experiment were to evaluate changes in body weight (BW) and water intake in cattle supplemented with an electrolyte solution upon feedlot arrival. Shipments of animals were weighed upon arrival at a commercial feedlot operation and moved to a set of holding pens where animals remained for a 3-d receiving period prior to entry into the feedlot. Sets of holding pens (n = 5 sets of 4 pens per treatment) were blocked by arrival date and randomly assigned to receive either a negative control (water) or an electrolyte solution during the receiving period. Daily free-choice fluid intake was monitored per pen, and animals were weighed at the end of the receiving period. Average fluid intake per animal was increased by 46.9 % (10.3 L/d; P = 0.013) in response to the addition of electrolyte. No differences due to treatment were observed in average origin BW, arrival BW, or BW recovery. This suggests that while recovery of BW was not affected, supplementing receiving cattle with an electrolyte solution may be an effective method of improving hydration status prior to feedlot entry. Future work aims to evaluate potential changes in morbidity and mortality during the finishing period following a similar supplementation strategy.

Effects of feeding lubabegron fumarate or ractopamine hydrochloride to beef × dairy crossbred steers raised under small-pen commercial feedlot conditions in western Canada

Effects of feeding lubabegron fumarate or ractopamine hydrochloride to beef × dairy crossbred steers raised under small-pen commercial feedlot conditions in western Canada

Application of growth models to South African Boer goat castrates and does under feedlot conditions

Mathematical models may aid researchers in describing biological processes, like growth, in animals. This study aimed to collect the body weight data of 18 Boer goat castrates and 20 Boer goat does, from birth until maturity, to model growth and determine growth trends. This is a novel investigation as sufficient information on an age-weight database for these two Boer goat sexes from birth to maturity, is lacking. Using age-weight data, four nonlinear models, namely the Brody, Gompertz, Logistic and Von Bertalanffy growth models, were plotted and evaluated. The model parameters of each growth model were compared for differences between the two sexes. The statistical effectiveness of fit was determined for each model using AIC and RMSE, with R2 also being considered. All models except the Brody model, predicted significantly heavier mature weights for castrates. The Brody model was deemed unfit to describe Boer goat growth as the function severely over-predict weights from birth until maturity for both sexes. The Von Bertalanffy (R2 = 91.3) and Gompertz functions (R2 = 91.3) showed the best fit for Boer goat castrates, while the Gompertz model (R2 = 95.1) showed the best fit for Boer goat does. The Gompertz function is the preferred model to depict Boer goat growth overall, as it accurately characterized growth of both sexes. According to the Gompertz model the age at which the inflection point of the growth curve was reached, did not differ significantly between castrates and does (141.80 days versus 136.31 days). There was also no significant difference in maturation rate between the two sexes.

Performance of Boran and Two Strains of Tanzania Short Horn Zebu Cattle Fed on Three Different Diets

A 3x3 factorial experiment was carried out to assess the performance of Boran breed (BRN), Iringa Red (IRR) and Singida White (SWT) strains of cattle fed on three different diets (D1, D2, and D3) under a feedlot condition. The diets contained hominy feed plus molasses (D1 or control), molasses and cassava meal (D2) and rice polishing (D3) as main energy sources. In addition, they contained sunflower seed cake as protein source, minerals and vitamins premix. Fifty-four (54) bulls of equal numbers of each strain, aged between 2 and 2.5 years and average initial weight of 194 ± 12.6 kg were randomly allocated in the three diets and housed in a feedlot structure. They were fed individually with their respective dietary treatments for 80 days, during which data on feed intake and growth performance were recorded. Thereafter 45 bulls with equal number of strains were slaughtered, and carcass characteristics were assessed and gross margins computed. The CP contents (g/kg) in the diets were highest in D2 (155), followed by D1 (141.7) and lowest (130) in D3. There were no significant (P>0.05) interaction effect of diet and breed/strain in all the parameters assessed on performance. Bulls fed on D2 grew faster (0.99 kg/d) and attained greater final weight (269.9 kg) and heavier carcasses (140.8 kg) followed by those fed on D1 with mean values of (0.92 kg/d), (258.1 kg) and (131.5 kg), respectively. The average dressing percentage followed a similar trend, being higher (P<0.05) in bulls fed on D2 (52.4) compared to those on D1 (51.7) and D3 (51.1). The BRN bulls had faster growth rates (1.04 kg/d) followed by the IRR (0.83 g/d), which had similar (P>0.05) average daily gain to that of SWT (0.83 g/d). The final weight of BRN bulls (267.4 kg) was not different (P>0.05) from that of IRR (257.5 kg), which was also found to be similar (P>0.05) to that of SWT (251.2 kg). The hot carcass weights followed similar trend, BRN having carcass weight (138.2 kg) similar (P>0.05) to IRR (130.4 kg), which happened to be not different (P>0.05) from that of SWT (129.3 kg). The mean dressing percentage was higher (P<0.05) for BRN (52.2) than other strains. It is concluded that value of weight gains and slaughter characteristics of Iringa red are comparable to those of Boran, thus for feedlot finishing farmers should be advised to select and use Iringa red bulls to obtain high carcass and large profit.

PSV-22 Productivity at Weaning of F1 Dorper X Pelibuey Ewes Carrying the Fecge Allele of the Ovine GDF9 Gene

Abstract The FecGE allele of the ovine GDF9 gene has been reported segregating in the Pelibuey hair type breed in México. Homozygous E/E ewes reproduce normally, in contrast to the sterility of homozygous ewes reported for other GDF9 variants. Thus, potential exists to cross homozygous and carrier Pelibuey ewes with meat type rams of low-prolificacy but well-adapted breeds to obtain F1 commercial flock ewes. The aim was to evaluate ewe productivity, as total lamb weight weaned (TWW), of FecGE carrier vs non-carrier F1 Dorper x Pelibuey ewes. Sixty one first lambing ewes (34 carrier and 27 non-carrier) equally served with two Texel rams were used. Management was under feedlot conditions. Genotyping was done by real time PCR (StepOnePlus) using the FAMACTTCAAACAGTTTCTTTTTMGBNFQ and VICTCAAACAGTGTCTTTTTMGBNFQ probes (Applied Biosystems). Type of birth (TB; twins vs single) and weaning (TW) were analyzed with PROC CATMOD of SAS. Fixed effects of ewe genotype (carrier vs non-carrier), contemporary group and ram of service were included in a logistic generalized linear model. Lamb weaning weights were adjusted to a common age of 75 d and by sex. Equivalent to male average birth lamb weight (ABW), average weaning lamb weight (AWW) and TWW per ewe were analyzed with PROC GLM of SAS. Carrier ewes had more twins (P < 0.01) for TB (75 vs 19.4 %) and TW (58.8 vs 21.7 %) than non-carrier ewes. Equivalent to male ABW on carrier ewes was less (P < 0.05; 3.17 ± 0.21 vs 3.97 ± 0.20 kg) than for non-carrier ewes but not difference (P > 0.05) was observed for AWW (21.96 ± 0.85 vs 22.93 ± 0.90 kg). Ewe productivity, as indicated by TWW, was greater (P < 0.05; 33.16 ± 1.78 vs 27.23 ± 1.88 kg) for FecGE carrier ewes than for the non-carrier ones. More research on this topic deserves further attention, especially under range conditions, with multiple parity ewes, different years and reproductive activity seasons, using a larger simple.

The Effect of a Bacillus Probiotic and Essential Oils Compared to an Ionophore on the Rumen Microbiome Composition of Feedlot Cattle.

The rising concern of antibiotic growth promoter use in livestock has necessitated the investigation into alternative feed additives. The effect of a probiotic and essential oils to an ionophore on the rumen microbiome composition of Bonsmara bulls raised under feedlot conditions was compared. Forty-eight Bonsmara weaners were allocated to four groups: a group with basal diet (CON) and three groups supplemented with monensin (MON), probiotic (PRO), and essential oils (EO). During the 120 days feeding period, rumen content was collected from four animals per group within each phase via a stomach tube for 16S rRNA and internal transcribed spacer (ITS) sequencing as well as volatile fatty acid analysis. In the starter phase, MON had a significantly lower acetate to propionate ratio and a higher Succinivibrionaceae abundance. The abundance of Lachnospiraceae was significantly higher in EO compared to MON. In the finisher phase, PRO had a significantly higher bacterial diversity. The alpha diversity did not differ between the fungal populations of the groups. The abundance of Proteobacteria was the lowest in PRO compared to the other groups. Limited variation was observed between the rumen microbiome composition of monensin compared to the other treatment groups, indicating that these alternatives can be considered.

Performance, carcass, and meat traits of locally adapted Brazilian cattle breeds under feedlot conditions.

Little is known about the performance, carcass, and meat traits of locally adapted cattle in Brazil. This study aimed to compare the growth, slaughter, and carcass traits as well as meat quality of two local breeds (Curraleiro Pé-Duro and Pantaneiro) with the Nelore breed. Fifteen 30-month-old steers of each breed were weighted (Curraleiro Pé-Duro = 264.80 kg; Nelore = 346.80 kg; Pantaneiro = 316.20 kg) and raised in a feedlot condition for 112 days, with measurements to assess growth and slaughter, visual and carcass and meat traits. Data were submitted to variance and multivariate analyses. Nelore and Curraleiro Pé-Duro had similar Gluteus medius depths. Pantaneiro and Curraleiro Pé-Duro were superior for leg compactness index (P < 0.05) and had higher eye muscle area than Nelore (P < 0.05). Although there was no difference in daily weight gain and slaughter weight between breeds, Curraleiro Pé-Duro had a lower initial weight (264.80 kg) when compared to Nelore (346.80 kg; P < 0.05). Nelore and Curraleiro Pé-Duro deposited more fat than Pantaneiro (P < 0.05), while Curraleiro Pé-Duro and Pantaneiro had more muscle than Nelore (P < 0.05), which also had more bone and a higher percentage of second-quality cuts (P < 0.05). Meat from Nelore also showed lower succulence than Pantaneiro (P < 0.05) and higher shear force than the other breeds (P < 0.05). Pantaneiro's meat had the most capacity to retain water (P < 0.05), lower shear force (P < 0.05), and was more succulent (P < 0.05) when compared to the other breeds. Multivariate analysis showed that Pantaneiro, Curraleiro Pé-Duro, and Nelore breeds can be considered distinct in growth, carcass, and meat traits, with the local breeds showing superior meat traits. The local breeds Curraleiro Pé-Duro and Pantaneiro presented characteristics similar or better to those of the Nelore, proving to be animals with great productive potential and generate high meat quality under feedlot conditions.

Feed Utilization and Growth Performance of Tanzania Shorthorn Zebu Fed Untreated or Urea Treated Rice Straws as Hay Replacement in Traditional Feedlot System

This study evaluated the effects of complete or partial replacement of <i>Cenchrus ciliaris </i>hay with untreated or urea treated rice straws on feed intake, growth performance, feed conversion ratio (FCR) and gross margin of Tanzania Shorthorn Zebu (TSHZ) cattle under feedlot condition. A total of 50 bulls with age of 2.5 - 3.0 years and mean initial weight of 132.4 ± 26.7 kg were assigned randomly to five treatments <i>i.e.</i> 100% <i>Cenchrus ciliaris </i>hay (CCH), 100% untreated rice straws (URS), 100% urea treated rice straws (TRS), 50% untreated rice straw + 50% <i>C. ciliaris </i>hay (URH) and 50% treated rice straw + 50% <i>C. ciliaris </i>(TRH). All animals were supplemented with a diet comprised of 53% maize bran, 25% molasses, 20% sunflower seed cake, 1.5% mineral premix and 0.5% table salt. The results show that average daily gain and weight gain did not differ (p > 0.05) among the treatments. However, animals on TRH showed the highest growth rate (770.0 ± 0.1 g/day) and weight gain (64.7 ± 4.4 kg), followed by those on TRS (growth rate = 725.0 ± 0.1 g/day, weight gain = 60.9 ± 4.4 kg) while those on URS had the lowest growth rate (599.0 ± 0.1 g/day) and weight gain (50.3 ± 4.4 kg). Animals fed TRS (9.8 ± 0.1) and TRH (8.9 ± 0.1) had lower (p ≤ 0.001) FCR than those fed CCH (10.3 ± 0.1), URS (11.9 ± 0.1) and URH (10.4 ± 0.1). The highest gross margin was obtained on animals under TRS (TZS 154,293.00) while the lowest was found on animals under CCH (TZS 120,450.00). Partial or complete replacement of hay with treated or untreated rice straws resulted into higher growth performance than feeding hay alone. Feeding animals with urea treated rice straws resulted into higher growth performance and better feed utilization compared to feeding hay or untreated rice straws. It is concluded that complete replacement of hay with urea treated rice straws resulted into high growth rate, lower FCR and high gross margin, hence, it is recommended as the best basal diet for fattening of TSHZ under traditional feedlot system.

The Effects of Breed and Residual Feed Intake Divergence on the Abundance and Active Population of Rumen Microbiota in Beef Cattle.

Simple SummaryThis study assessed the effects of breed and feed efficiency on rumen microbiota in a total of 96 beef steers, with three breeds and divergent residual feed intakes. The abundance and activity of the total bacteria, archaea, protozoa, and fungi in the rumens were estimated by measuring the copy numbers of their respective marker genes at both DNA (abundance) and RNA (activity) levels. Our results evidence the effect of breed on four microbial groups. Past studies have been mainly focused on bacteria and archaea, yet ours is the first study to reveal the effect of breed (host genetics) on rumen eukaryotes, suggesting that host genetics can regulate the rumen microbiota as a whole, highlighting the potential of manipulating and obtaining desirable and efficient rumen microbiota using breeding and genetic selection.To assess the effects of residual feed intake (RFI) and breed on rumen microbiota, the abundance (DNA) and active population (RNA) of the total bacteria, archaea, protozoa, and fungi in the rumen of 96 beef steers from three different breeds (Angus (AN), Charolais (CH), and Kinsella Composite (KC)), and divergent RFIs (High vs Low), were estimated by measuring their respective maker gene copies using qRT-PCR. All experimental animals were kept under the same feedlot condition and fed with the same high-energy finishing diet. Rumen content samples were collected at slaughter and used for the extraction of genetic material (DNA and RNA) and further analysis. There was a significant difference (p < 0.01) between the marker gene copies detected for abundance and active populations for all four microbial groups. AN steers had a higher abundance of bacteria (p < 0.05) and a lower abundance of eukaryotes (protozoa and fungi, p < 0.05) compared to KC steers, while the abundance of protozoa (p < 0.05) in the AN cattle and fungi (p < 0.05) in the KC cattle were lower and higher, respectively, than those in the CH steers. Meanwhile, the active populations of bacteria, archaea, and protozoa in the KC steers were significantly lower than those in the AN and CH animals (p < 0.01). This work demonstrates that cattle breed can affect rumen microbiota at both the abundance and activity level. The revealed highly active protozoal populations indicate their important role in rumen microbial fermentation under a feedlot diet, which warrants further study.

O2 Determining the energy and protein requirements of cattle receiving liver abscess controlling rumen modifier under feedlot conditions

O2 Determining the energy and protein requirements of cattle receiving liver abscess controlling rumen modifier under feedlot conditions

MAGRARIO: UN NUEVO GENOTIPO PARA PRODUCIR CARNE OVINA DE CALIDAD

Generally there is poor tradition to produce and to commercialize heavy lean lamb carcasses. To achieve a better product for the ovine meat market Ideal (Polwarth) breed ewes were backcrossed to Texel breed rams (breed recognized to reduce carcass fat). Ideal breed (I) is one of the most ordinary breeds in Argentina. However, when their lambs are reared in feed-lot conditions, a high fat content is found in their lamb carcasses. After three generations of backcrosses followed by a breeding program for increase male lamb weaning weight and female fertility a new genotype was obtained for the local ovine meat production systems. This new genotype registered as Magrario (M) was obtained at Villarino Field Station of UNR (Zavalla, Santa Fe, 33º S, 61º W). It was verify that M produced more lean meat than I breed under feet lot conditions. M rams were introduced in flocks of Hampshire Down (HD) breed to evaluate lamb crosses with lean meat. Genotype M was compared under feed lot conditions with HD lambs during two months in the post weaning. Also crosses (MxHD), (MxI) and (IxHD) were evaluated in the same conditions. At the end of the experiment ultrasonic methods were used to evaluate fat depot on Longissimus dorsi. The (MxHD) showed a reduction of 20% respecting to HD. These results suggested that M genotype could be a useful paternal genotype to reduce fat depots when the aim is to produce lamb crosses under feed lot conditions in a short period of time. Key words: ovine, lean meat, feed lot, crossing.

SOME CARCASS TRAITS OF RED SOKOTO GOAT OF NIGERIA

A study was conducted to investigate the meat producing potential of the Red Sokoto goat of Nigeria. The twelve Red Sokoto male goats used were slaughtered at an average age of 3 years and liveweight of 27.63kg. The dressing out percentage was 49.3%. The bone to meat ratio of the leg and loin cuts was 0.28. The longissimus dorsi muscle was 10.53 cm2. It is concluded that the Red Sokoto goat has a good potential for meat production. More detailed studies are, howeverneeded in order to exploit the fattening ability of the breed under range and feedlot conditions.

Prediction of dry matter intake by feedlot beef cattle under tropical conditions

Context Dry matter intake (DMI) is the variable that most affects beef cattle performance in feedlot conditions. Accurate prediction of DMI is essential because it is the basis for calculating nutritional requirements for maintenance and production. Aims A meta-analysis was conducted to develop DMI prediction models for feedlot beef cattle under tropical conditions, and to compare the models with those proposed by the National Research Council, USA, in 2000 and 2016, as well as those recommended by the Brazilian System of Nutritional Requirements (BR-Corte) and published by Azevêdo and colleagues in 2010 and 2016. Methods The dataset was created from 56 published studies conducted under tropical conditions. The dataset was randomly separated into two subsets for statistical analysis. The first subset was used to develop the models to predict DMI, and the second to evaluate the adequacy of the prediction models. The models were developed by using mixed linear and nonlinear analysis. Key results A nonlinear model and a linear model to predict DMI are proposed. These models were similar in terms of accuracy and were superior to the other evaluated models. The nonlinear and linear models explained, respectively, 59% and 62% of the DMI variation and had greater accuracy and precision than the other models. The 2016 model used by BR-Corte explained 55% of the DMI variation, and underestimated it at 0.20 kg/day. The remaining three models presented a systematic constant bias and were not adequate for predicting DMI. Conclusion The proposed nonlinear and linear prediction models of beef cattle in feedlot developed under tropical conditions are more precise and accurate than those recommended by the National Research Council and the 2010 model used by BR-Corte. They also present better prediction quality of DMI from beef cattle in feedlots under tropical conditions than the 2016 model used by BR-Corte. Implications The proposed models in the present study are the most suitable for use in predicting the DMI of beef cattle under tropical conditions.

Comparative effects of feeding citrus pulp and grape pomace on nutrient digestibility and utilization in steers

Feedlot beef production in tropics and subtropics is being limited by shortage of feed ingredients due to prolonged droughts resulting in high prices of cereal grains and reduced profitability. To alleviate feed shortages and increase profitability for the feedlot industry, it is important to explore underutilized non-conventional resources such as fruit by-products. The current study compared the nutrient intake, digestibility and utilization effects of feeding either 150 g/kg of dried citrus pulp (DCP) or grape pomace (DGP) as alternative dietary fibre sources to 7 months-old Angus steers (281 ± 15.7 kg) under feedlot conditions. Twenty-four steers were assigned to three dietary treatments (8 steers/treatment) in a completely randomised design. Each steer was treated as an experimental unit. Steers were adapted to diets for 21 d followed by 7 d of sample collection during which nutrient intake, digestibility, rumen fermentation parameters, nitrogen retention and microbial N supply were determined. All the data were analysed using the GLIMMIX procedures. Overall, steers fed DGP had the greatest dry matter intake (DM), organic matter (OM) crude protein (CP), ash free neutral detergent fibre (aNDFom), ether extract (EE) and starch intake followed by DCP and control (CON) diets (P ≤ .05). Apparent digestibilities of DM, OM and aNDFom were higher (P ≤ .05) for DCP diet compared to DGP and CON diets. Feeding DCP and DGP diets increased ruminal concentrations of total volatile fatty acids, acetate and isovalerate, and acetate to propionate ratio, and reduced propionate concentrations compared to the CON diet (P ≤ .05). The steers fed the CON diet had the greatest urinary excretions of allantoin, uric acid and total purine derivatives followed by those fed the DCP and DGP diets (P ≤ .05). Nitrogen intake, faecal nitrogen (N), N retention and N efficiency utilization were in the order of DGP > DCP > CON diets (P ≤ .05). Overall, feeding DGP as alternative fibre source to wheat bran improved nutrient intake, retention and efficiency of N utilization but reduced apparent nutrient digestibility compared to DCP. Current finding suggests that DGP may be a better fibre substitute for wheat bran in beef diets than DCP.

Premium lamb production of South African sheep breed types under feedlot conditions

An increasing number of producers opt to finish their lambs in on-farm feedlots. Therefore, detailed production information is required to implement precision finishing of lambs of different genotypes. Precision finishing monitors growth, feed intake and efficiency to optimize management. In this study, feedlot production characteristics of Dohne Merino, Dormer, Dorper, Meatmaster, Merino, Namaqua Afrikaner, and South African Mutton Merino (SAMM) lambs were evaluated. The lambs were reared in a feedlot and fed a diet with 10.41 MJ metabolizable energy (ME)/kg feed and 19.06% crude protein. Feed intake and body weight were recorded weekly from an initial weight of 30 kg until they had the subcutaneous fat cover needed to produce an A2 carcass. Subcutaneous fat was measured on the Longissimus lumborum muscle with an ultrasound scanner. Dorper, Meatmaster and Namaqua Afrikaner had the shortest rearing periods in the feedlot, and were market ready at a lower live weight (P &lt;0.05). As a result, these lambs consumed less feed in the feedlot. Namaqua Afrikaner and Merino lambs were least efficient: 7.08 and 5.63 kg feed/kg gain, respectively. Dohne Merino, Dormer, Dorper, and Meatmaster rams and Dorper ewes were more efficient; approximately 3.58 kg feed/kg gain. Dohne Merino and Dormer rams had the highest growth rates: approximately 465 g/day. The end weights described in this study could be used as an indication for producers of the ideal slaughter weights for breeds of different maturity types.Keywords: average daily gain, fat deposition, feed efficiency, rearing period

Methane Emissions, Performance and Carcass Characteristics of Different Lines of Beef Steers Reared on Pasture and Finished in Feedlot.

Simple SummaryThe livestock sector is a significant contributor to global greenhouse gas emissions, with cattle representing 62% of CO2 emissions. Genetic selection is a tool that has the potential to reduce emissions from rumen fermentation and can be adopted in grazing and feedlot systems. Therefore, the purpose of this study was to evaluate steers from a new line of the Canchim breed (5/8 Charolais, 3/8 Zebu) derived by genetic selection improvement, and formed and maintained as a closed herd since 1998, in regards to performance, carcass dressing, and enteric methane emissions, when compared with the old line formed and maintained as a closed herd since 1960. Animals from the new line of the Canchim breed should be used for rearing on pasture to obtain greater liveweight gain. However, genetic improvement in Canchim breed does not guarantee animals with lower methane emissions under grazing conditions. For the finishing feedlot phase, increased liveweight gain, improved feed conversion, and a better carcass dressing percentage are obtained using animals from the new line of Canchim breed. The new line also leads to higher daily feed intake and higher daily liveweight gain, but with the same methane emissions per kg of animal liveweight than the other lines.The present study aimed to investigate whether different lines of a composite breed (5/8 Charolais × 3/8 Zebu), formed at different times, and genetically improved, would result in differences in animal performance, enteric methane emissions, and carcass traits. Forty-six Canchim steers (15 months, 280 ± 33 kg liveweight) from three different lines were used: old, new, and their cross. These three breed lines were considered the treatments (arranged in four randomized blocks based on initial liveweight) and were evaluated under grazing and feedlot conditions in relation to the performance and emission of enteric methane. During the grazing period, the new line was found to be superior to the old only in relation to the average daily liveweight gain (0.692 vs. 0.547 kg/day), and with no differences in relation to the cross line (0.692 vs. 0.620). In the feedlot finishing phase, only the average daily liveweight gain was significantly higher in the new line compared to the cross and old line (1.44 vs. 1.32 and 1.23 kg/day). The new and cross lines demonstrated higher dry matter intake when compared to the old line (10.25 and 10.42 vs. 9.11 kg/day), with the crossline animals demonstrating the best feed conversion. The new line showed higher enteric methane emissions compared to the old line (178 vs. 156 g/day). The line had an effect on the carcass dressing of the animals, with greater fat thickness in carcasses from the new and cross lines than the old line (4.4 and 3.8 vs. 3.2 mm). Canchim cattle selected for improved productive performance characteristics does not guarantee animals with lower methane emissions under grazing conditions; while in feedlots, can lead to increased daily feed consumption, and hence, to higher emissions of methane.

Effect of High Potency Growth Implants on Average Daily Gain of Grass-Fattened Steers.

Simple SummaryImproving efficiency in beef cattle production requires the adoption of technologies that are low cost but high in return. High potency growth-promoting implants (HGPs) are widely used under feedlot conditions but there are few reports of their use under grazing conditions. We conducted a trial to assess whether the use of high potency HGPs have advantages for grass-finished cattle. Our results were similar to those reported for feedlot cattle, showing that the quality of the pastures was good enough to take advantage of the HGP technology, generating a marginal income that justifies the use of technology under grazing conditions.High potency growth promoter implants (HGPs) are widely used under feedlot conditions but there are few reports under grazing conditions. The study’s goal was to assess the effect of HGPs on the average daily gain of steers fattened in pastures. A total of 57 crossbreed steers (Hereford × Angus)—initial body weight = 356.65 kg ± 5.04 (SEM)—were randomly allocated to one of three groups: Control without HGP (n = 19), Synovex group (n = 17), and Revalor group (n = 21). The fattening period was 67 days using paddocks of Lolium perenne L. and Trifolium repens L. Body weight was recorded three times in the period. The data were analyzed using an analysis of covariance with a level of significance of 5%. The average daily gain (ADG) (1.55 ± 0.07 and 1.48 ± 0.09 kg/d) and the total weight gain (103.4 ± 4.9 and 99.2 ± 5.8 kg) were similar for Revalor and Synovex, respectively (p > 0.05). Moreover, HGP groups showed higher ADG and total weight gain (p < 0.01) than the control group (ADG = 0.93 ± 0.08 kg/d and a total weight gain of 62.2 ± 5.2 kg). Final body weights were 527.8 ± 8.5 kg and 512.2 ± 9.9 kg for Revalor and Synovex, respectively; and 479.9 ± 10.1 kg for Control. In conclusion, grazing-finished steers showed better performance when high potency HGPs were used, improving the ADG and final live body weight, generating a marginal income that justifies the use of the technology under grazing conditions

Growth performance of Lowline Angus x Thai native crossbred beef under tropical condition.

Thai native cattle (Bos indicus) have high fertility rates and strong mothering abilities; however, their slight size, slow growth rate and low meat quality have not proved suitable for a commercial fattening system. Their progeny from crossbreeding with exotic sire particularly the Bos Taurus could present greater production performance. Lowline Angus sires and frozen semen were used to produce Lowline Angus x Thai native crossbreds. All cattle were raised in the same condition which was mainly through a grazing system. Throughout 5years of data collection, calves' gender, birth weight, and weight gains were recorded until 1year of age. There was no interaction effect between calves' gender, breed, and birth season on weight at birth and yearling, as well as growth rate. The birth weight of male calves (14.0kg) were greater than female calves (13.3kg). The calves' birth weights did not differ between levels of Lowline Angus blood, but all crossbred males were found to be significantly bigger than indigenous females. It must be noted that yearling weight did not differ between breeds. However, females 75% Lowline Angus, 25% Thai native crossbred (139.3kg) weighed significantly higher than Thai native purebred females (115.9kg). The calves' birth weights had positive correlation with Lowline Angus blood levels: birth weights increased when Lowline Angus blood levels were increased. The sharpness in the growth curve of Lowline Angus crossbreds was higher than purebred Thai indigenous cattle. Moreover, the 25% Lowline Angus crossbred had the highest graph slope as opposed to the 50% or 75% Lowline Angus crossbred. The growth performance of Lowline Angus x Thai native crossbred was shown unsuccessful under low-quality grazing situation. Additive effect of the crossbred presented quite low but well adapted to tropical environment. Greater productivity performance of the crossbred possibly will be excess with a higher quality feedlot condition.

Carcass and meat quality attributes of Malawi Zebu steers fed &lt;i&gt;Vachellia polyacantha&lt;/i&gt; leaves or &lt;i&gt;Adansonia digitata&lt;/i&gt; seed as alternative protein sources to &lt;i&gt;Glycine max&lt;/i&gt;

To enhance smallholder beef farmers’ capacity to cope with animal feed shortages, especially dietary protein induced by climate change, it is important to evaluate the feeding value of low-cost protein sources naturally available in the environment. The aim of the study was to evaluate carcass and meat quality of Malawi Zebu steers fed diets containing Adansonia digitata (baobab) seed meal or Vachellia polyacantha (white thorn tree) leaf meal as alternative protein sources to Glycine max (soybean) under feedlot conditions. Thirty Malawi Zebu steers (181 ± 21.4 kg body weight; 29 months old) were individually fed forage-based diets made up of rangeland hay and maize bran, with either baobab seed meal, Vachellia leaf meal or soybean meal as a protein source for 120 days. At the end of the feeding trial, animals were slaughtered and the longissimus thoracis et lumborum muscle sampled for meat quality analyses. Steers fed soybean and baobab diets had higher subcutaneous fat thickness, carcass weights than those fed the Vachellia diet. Meat from steers fed the Vachellia and baobab diets had higher ultimate pH and water-holding capacity, and lower drip and cooking losses than meat from steers fed the soybean diet. Feeding baobab and Vachellia diets produced beef with lower lightness (L*) values than the soybean diet, characteristic of dark, firm and dry (DFD) beef. Steers fed the baobab diet had the highest gross profits followed by those fed the Vachellia and soybean diets, respectively. Overall, feeding the baobab and Vachellia diets improved gross profit but produced DFD beef compared to the soybean diet.Keywords: beef cattle, baobab seed, soybean meal, smallholder production

Ingestive behaviour of steers grazing Brachiaria brizantha cultivar Marandu and in feedlot in Brazil.

The objective of this study was to evaluate the ingestive behaviour of steers grazing Brachiaria brizantha cv. Marandu and in feedlot regimen in Brazil. Fifty crossbred steers, with an average weight of 275 ± 8.18kg, were distributed in a completely randomised design with five treatments and ten replicates per treatment (mineral supplementation, nitrogen supplementation, and concentrate supplementation at 0.1 and 0.2% of body weight and under feedlot conditions). Ingestive behaviour was assessed every 5min for 24h. No difference (P > 0.05) was found for grazing time among grazing systems. Conversely, rumination, idle, feeding, and chewing times showed differences (P < 0.05) only for feedlot animals. The time spent feeding at the trough was higher (P < 0.05) in animals receiving concentrate supplementation. The bite rate and the number of bites per day were similar (P > 0.05) among grazing systems. Feed and rumination efficiencies of dry matter and neutral detergent fibre corrected for ash and protein showed differences (P < 0.05) only in feedlot animals. Therefore, ingestive behaviour of steers varies with the raising system. Overall, feedlot animals showed better performance than grazing animals did, most likely due to longer rest periods.