Intermittent Grazing Research Articles

Performance, Carcass Traits, and Meat Fatty Acid Profile of Post-Weaning and Finishing Zebu Steers on Tropical Pasture with Three Low-Intake Supplementation Strategies.

The study aimed to evaluate the effects of three supplementation strategies on intake, apparent digestibility, feeding behavior, performance, carcass traits, proximate composition, and the fatty acid profile of meat from steers on tropical pasture during the post-weaning and finishing stages. The experiment involved 33 1/2 Holstein × 1/2 castrated Zebu steers weighing 335 ± 42.90 kg, aged 22 ± 2 m. The animals were managed on Urochloa brizantha cv. Marandu using an intermittent grazing system with continuous stocking and variable stocking rates for 310 days. The supplementation strategies were as follows: MS/US (mineral salt/urea supplementation): mineral salt in the rainy season and mineral salt with urea in the dry season; US/PS1 (urea supplementation/protein supplementation): mineral salt with urea in the rainy season and protein supplement at 1 g/kg body weight (BW) in the dry season; and PS1/PS2 (protein supplementation 1/protein supplementation 2): protein supplement at 1 g/kg BW in the rainy season and 2 g/kg BW in the dry season. The dry matter intake did not differ significantly (p > 0.05) between strategies. However, the post-weaning PS1/PS2 strategy resulted in higher (p < 0.05) crude protein intake. The final body weight did not differ (p > 0.05) between the strategies, but the average daily gain in post-weaning and finishing was higher (p < 0.05) for MS/US (restricted) animals. Carcass weight, subcutaneous fat thickness, and lipid content in meat were significantly higher (p < 0.05) for steers in the PS1/PS2 group. Steers finished on MS/US produced meat with a higher content of polyunsaturated fatty acids and ω-3 fatty acids (p < 0.05). Concentrate supplementation at 1 g/kg BW during the rainy season and 2 g/kg BW during the dry season is recommended for post-weaning and finishing steers on tropical pasture.

Impact of energy-mineral supplementation on the performance of young bulls from varied genetic groups during the pasture growth phase and in subsequent feedlot evaluation

ABSTRACT The aim of this study was to evaluate the performance of young bulls from different genetic groups supplemented on pasture, and to assess the residual effect of supplementation during the feedlot phase. The experiment was divided into two stages, where young bulls received pasture supplementation during the rainy season (mineral and mineral-energetic), and subsequently, were sent to the feedlot. For this purpose, three genetic groups were tested (Nelore, ½Canchim½Nelore, ½Brangus½Nelore), along with two supplementation strategies (mineral and mineral-energetic). The animals during the rearing phase had access to Cynodon spp. cv. Tifton 85 pasture, being managed under the intermittent grazing method. The ½Brangus½Nelore animals exhibited higher weights at the beginning and end of the feedlot period. Regarding the average daily gain, no differences were observed between the supplementation strategies, resulting in an average value of 1.58 kg day−1. Animals treated with mineral supplement during rearing showed an increase of 11.89% in dry matter intake for ½Brangus½Nelore, while for ½Canchim½Nelore animals, this supplementation strategy resulted in increases of 5.38%. The ½Brangus½Nelore animals showed higher initial and final weights in the feedlot. While the supplementation strategy does not impact the performance of the animals in the final phase of the production cycle.

Lupine-induced crooked calf syndrome: mitigation through intermittent grazing management of cattle.

Lupines are responsible for a condition in cattle referred to as "crooked calf syndrome" (CCS) that occurs when pregnant cattle graze teratogenic lupines. A proposed management strategy to limit these types of birth defects includes utilizing an intermittent grazing schedule to allow short durations of grazing lupine-infested areas interrupted by movement to a lupine-free pasture. The objective of this study was to determine if an intermittent schedule of ten continuous days of lupine treatment followed by 5 d off treatment would be sufficient to decrease, or prevent, the incidence of lupine-induced malformations. Continuous dosing of the teratogenic lupine (Lupinus leucophyllus) to pregnant cows for 30 d during the most susceptible stage of pregnancy (gestation days 40 to 70) resulted in severe skeletal birth defects in their calves. However, intermittent dosing of the teratogenic lupine demonstrated that interrupted intake of lupine reduced the severity, or eliminated, permanent skeletal malformations in calves born to cows dosed lupine. Toxicokinetic and ultrasound data demonstrated a clear inverse correlation between serum anagyrine (the primary teratogenic alkaloid in some lupines) concentrations in the dam and fetal movement. In the intermittent group, fetal movement quickly returned to normal after lupine feeding stopped and remained normal until lupine treatment resumed. Therefore, interrupting lupine intake for at least 5 d through an intermittent grazing program could reduce the severity of the CCS. Furthermore, this method would allow ranchers to move cattle back into lupine pastures after a brief interruption, which would allow for more efficient utilization of forage resources.

Managing a mixed sward to maintain species and functional diversity

The intensification of animal production systems to meet the increasing demand for animal products may undermine environmental sustainability. One solution is to establish pastoral environments with diverse plant functional groups, promoting sustainable intensification by enhancing ecosystem services such as nutrient cycling and soil health. However, maintaining the species diversity in such systems, particularly those with grasses and legumes, remains a challenge. Although using the critical leaf area index (LAI) and its corresponding height has proven useful in managing single-species stands, there is a need for further investigation of the criteria for managing more complex swards. This study aimed to identify the management strategies for coupling species diversity and forage production in mixed pastures containing grasses and legumes. The pastures included five species: Tifton 85 (Cynodon spp.), kikuyu grass (Cenchrus clandestinus), pintoi peanut (Arachis pintoi), white clover (Trifolium repens) and birdsfoot trefoil (Lotus corniculatus). Two management heights (17 and 23 cm) and three nitrogen fertilizer rates (50, 150, and 250 kg ha−1) were combined in a randomized complete block design, with a factorial arrangement and three replicates per treatment. The pastures were subjected to intermittent grazing with a 40% defoliation severity, and the experimental period lasted for three warm seasons (November – April) from 2020 to 2022. Forage accumulation was similar for both management heights; however, shorter heights (17 cm) reduced species diversity and higher nitrogen rates increased forage production. Tifton-85 and kikuyu grasses dominated the canopy and coexisted in similar proportions across all treatments. However, higher nitrogen application rates decreased species diversity and dissimilarity in community traits. Our findings suggest that grazing pastures at shorter heights (17 cm) can be detrimental to canopy diversity, whereas managing mixed swards at a pre-grazing height close to the critical LAI (approximately 23 cm for a predominantly Tifton 85 and kikuyu grass mixture) can promote greater species diversity without compromising forage production. Additionally, our data suggest that functional diversity is enhanced when grasses experience suboptimal nitrogen nutrition indices (NNI no greater than 0.8). However, further research is required to fully understand this relationship.

Technologies used in ruminant grazing management: an integrative review.

The objective of this study was to identify the main technologies used in the management of ruminant grazing. We developed a review protocol in which the search terms were previously tested and based on the PVO strategy to determine the guiding question (population [P]: domestic ruminants; variables [V] of interest: grazing management technologies; and outcomes [O]: intake, performance, and productivity of animals raised exclusively on pasture). The guiding question was the following: What technologies are used in the grazing management of domestic ruminants on pasture? The databases used were SCOPUS (Elsevier), SciELO Citation Index, Science Direct, and Wiley Online Library, and the search was carried out until October 15, 2021. The search identified 2683 research articles; however, only 43 were considered eligible and included due to their methodological robustness for data extraction. The most commonly used species were Lolium multiflorum and Lolium perenne (20%), Panicum maximum (18%), and Brachiaria brizantha (14%). The most widely used grazing methods were continuous grazing (53.4%) and intermittent grazing (39.5%). Among the technologies, the most widely adopted were pasture height (55.8%) and herbage allowance (11.6%). The most frequent sampling methods were the use of a ruler (37.2%) and measuring stick (13.9%) to measure the height, and clipping with a frame (18.6%) to measure herbage allowance. The animals used in the included studies were cattle (n = 1335), sheep (n = 839), and goats (n = 41). Pasture height and herbage allowance were the most widely used grazing management technologies, with the data concentrated mainly in Brazil, in studies with continuous grazing by cattle.

Morphogenetic and structural traits of Ipyporã grass subjected to nitrogen fertilization rates under intermittent grazing

ABSTRACT: This study examined the effects of annual nitrogen (N) rates of 100 and 200 kg ha-1 on the morphogenetic and structural traits of Ipyporã grass (Brachiaria brizantha × Brachiaria ruziziensis) under intermittent grazing during the seasons of the year. The experiment was laid out in a randomized-block design with two treatments and three area replicates. Ipyporã grass pastures were grazed by beef cattle. Morphogenetic and structural traits of the forage canopy were evaluated using the marked-tiller technique. Forage accumulation and tiller density (TD) were also evaluated. Significant interaction effects (P &lt; 0.05) between N rates and seasons were observed for the rest period, leaf lifespan (LLS), phyllochron, stem elongation rate (SER) and final leaf length (FLL). During winter, the rest period was shorter (40 vs. 50 days) in the pastures fertilized with 200 kg ha-1 N. Conversely, in winter, the pastures fertilized with 100 kg ha-1 N showed higher LLS, SER and phyllochron values, but lower FLL values. There was no isolated effect of N rates (P &gt; 0.05) on forage accumulation rate; leaf appearance, elongation or senescence rates; leaf:stem ratio; or TD. However, the effect of seasons was significant for these variables, with the highest values occurring during spring and summer. The use of 200 kg ha-1 N in Ipyporã grass pastures reduces the seasonality of forage production.

Effect of pasture management on enteric methane emissions from goats.

The effect of pasture management on CH4 emissions was investigated from goats in a tropical climate. Two experiments were conducted in a "Tanzania Guinea grass" (Panicum maximum Jacq.) pasture to assess enteric CH4 production in a completely randomized design. Emissions from light, moderate, and heavy grazing intensities were analyzed in the first experiment, and variations between grazing days were explored in the second experiment. Grazing intensity was defined as 2.4, 1.6, and 0.8 post-grazing leaf area index. Pasture management employed intermittent grazing with variable stocking rate using Anglo Nubian female adult goats. SF6 tracer gas technique was used to measure CH4 production. Grazing intensity was not found to affect CH4 emissions per animal, dry matter forage intake (DMI), and gross energy (GE) intake. However, the second experiment showed that CH4 production was influenced by the grazing day. CH4 emissions were 18.1gday-1, and the variables were 0.88gkg-1 of metabolic weight, 17.45gkg-1 of DMI, and 5.5% of GE. CH4 production increased linearly with the grazing day, possibly reflecting a reduction in forage quality. These findings suggest that the day of occupation in intermittent grazing has a greater effect on CH4 emissions than that by grazing intensity and that a single day grazing of Tanzania Guinea grass could mitigate CH4 emissions.

Pasture characteristics and productive performance of dairy cows under two grazing management strategies

The objective of this work was to evaluate the supply, morphological and chemical composition of forage, performance and milk composition of crossbred cows managed in Megathyrsus maximus cv. Tanzania in intermittent grazing system with fixed and variable defoliation intervals according to the interception of 95% of photosynthetically active radiation by the canopy. The experimental design was a randomized complete block design with two treatments and two area replications. In each grazing cycle the supply, morphological composition, forage nutritive value, dry matter intake, milk production and composition were determined. The experimental area was 4.0 hectares, divided into two blocks of 2 hectares. Each block was subdivided into 22 pickets (11 for each treatment) totaling 44 pickets with an area of 909 m2 each. Significant differences (P &lt; 0.05) were observed for leaf blade content, in vitro digestibility of dry matter and forage crude protein, dry matter intake, individual and area milk production and lactose content milk, being the highest values found in the pastures managed with variable defoliation interval. Thus, the defoliation interval defined by the 95% interception of the photosynthetically luminosity leads to higher leaf blade proportions in the forage canopy, resulting in higher individual milk yield and per unit area, but with a loss of protein and total solids contents of milk.

Estratégias de manejo do pastejo para capim-xaraés (Brachiaria brizantha cv. Xaraés)

Objetivou-se com este estudo, avaliar os efeitos de duas estratégias de pastejo intermitente, com 24 dias fixos de descanso e com 95% de interceptação luminosa em capim-xaraés. Para a avaliação das características produtivas, estruturais e bromatológicas foi utilizado o delineamento inteiramente casualizado com medidas repetidas no tempo, com quatro ciclos de pastejo e duas estratégias de pastejo. Para o consumo dos animais foi utilizado o delineamento inteiramente casualizado em arranjo fatorial 2 x 3, sendo duas estratégias de pastejo e três dias de ocupação, e para a taxa de lotação utilizou-se o arranjo 2 x 4 (duas estratégias e quatro ciclos de pastejo). Não houve efeito para as variáveis: disponibilidade, estrutura e composição bromatológica da forragem, com exceção para interceptação luminosa e proteína bruta, onde o tratamento com IL obteve maior valor de interceptação luminosa (2,73% superior que o DF) e menor teor de PB (1,08% inferior ao tratamento DF). Para o consumo de matéria seca houve efeito (P

Long-term ecological research in southern Brazil grasslands: Effects of grazing exclusion and deferred grazing on plant and arthropod communities.

Grazing exclusion may lead to biodiversity loss and homogenization of naturally heterogeneous and species-rich grassland ecosystems, and these effects may cascade to higher trophic levels and ecosystem properties. Although grazing exclusion has been studied elsewhere, the consequences of alleviating the disturbance regime in grassland ecosystems remain unclear. In this paper, we present results of the first five years of an experiment in native grasslands of southern Brazil. Using a randomized block experimental design, we examined the effects of three grazing treatments on plant and arthropod communities: (i) deferred grazing (i.e., intermittent grazing), (ii) grazing exclusion and (iii) a control under traditional continuous grazing, which were applied to 70 x 70 m experimental plots, in six regionally distributed blocks. We evaluated plant community responses regarding taxonomic and functional diversity (life-forms) in separate spatial components: alpha (1 x 1 m subplots), beta, and gamma (70 x 70 m plots), as well as the cascading effects on arthropod high-taxa. By estimating effect sizes (treatments vs. control) by bootstrap resampling, both deferred grazing and grazing exclusion mostly increased vegetation height, plant biomass and standing dead biomass. The effect of grazing exclusion on plant taxonomic diversity was negative. Conversely, deferred grazing increased plant taxonomic diversity, but both treatments reduced plant functional diversity. Reduced grazing pressure in both treatments promoted the break of dominance by prostrate species, followed by fast homogenization of vegetation structure towards dominance of ligneous and erect species. These changes in the plant community led to increases in high-taxa richness and abundance of vegetation-dwelling arthropod groups under both treatments, but had no detectable effects on epigeic arthropods. Our results indicate that decision-making regarding the conservation of southern Brazil grasslands should include both intensive and alleviated levels of grazing management, but not complete grazing exclusion, to maximize conservation results when considering plant and arthropod communities.

Introduction of forage legumes into Aruana Guineagrass pasture

The experiment was developed at the Instituto de Zootecnia in Nova Odessa-SP. It was designed to evaluate forage mass, forage legumes ratio in the available forage mass and the transfer potential of the nitrogen fixed by the forage legumes to Aruana Guineagrass pasture grazed by lambs under intermittent grazing. The treatments consisted of the introduction of four accessions of forage legumes in the pasture of Megathyrsus maximum cv. Aruana and a treatment of Aruana Guineagrass pasture (without legumes), totalling five treatments. The Aruana Guineagrass pasture was established five years ago. The forage legumes treatments were: Neonotonia wightii NO 253 (Perennial soy NO 253), Neonotonia wightii NO 2348 (Perennial soy NO 2348), Macrotyloma axillare NO 279 (Macrotyloma legume) and Calopogonium mucunoides NO 1194 (Calapo legume). The experimental design was made up of random blocks with three replicates. The Calapo legume showed the lowest mean forage mass in the three seasons (400 kg/ha). The mean forage mass of the Perennial soy NO 253, Perennial soy NO 2348 and Macrotyloma legume did not show significant differences in the three seasons. Furthermore, the Calapo legume ratio in the pasture was the lowest in the total forage mass (13%) among the intercropped forage legumes (31.9% at 43.2%). Perennial soy NO 253, Perennial soy NO 2348 and Macrotyloma legume showed suitable ratio in the forage mass when intercropped with Aruana Guineagrass. These forage legumes also promoted the highest crude protein content in the Aruana Guineagrass. Thus, it is possible to advise the introduction of Perennial soy NO253, Perennial soy NO2548 or Macrotyloma legume in established Aruana grass pasture.

Effects of grazing management on leaf litter decomposition and soil microbial activities in northern Iranian rangeland

The effects of rangeland management on biogeochemical processes that control the exchange of C and nutrients between the soil and plant are not well understood. For this purpose, aboveground litter properties and decomposition of three dominant species (Artemisia aucheri, Astragalus podolobus, and Eurotia lanata) were studied in four rangeland management systems of northern Iran including continuous grazing, intermittent grazing, and two non-grazing sites (i.e. woody and non-woody rangelands). We tested the following hypotheses: (i) woody rangeland improves litter quality, with a higher rate of decomposition, soil fertility and biochemical functions compared to non-woody rangeland and grazed sites, and (ii) continuous grazing reduces microbial C and N turnover. Plant residues from all rangeland species in the grazing and non-grazing areas were collected and soil samples were taken and analyzed for chemical properties and microbial activities. Based on the obtained data, litter decomposition was faster under woody rangeland ecosystem (Artemisia aucheri > Astragalus podolobus > Eurotia lanata) compared with the other study sites. The results revealed improved litter quality and increased soil available nutrients, as well as C and N mineralization for the woody rangeland, whereas under intermittent grazing the soil C/N ratio, microbial basal respiration (BR), substrate induced respiration (SIR) and microbial biomass C (MBC) increased. Soil pH, EC, qCO2 (BR: MBC) were significantly higher under continuous grazing, but with lower contents of soil organic C, total N, and available Mg. Furthermore, C and N stocks, microbial entropy (MBC: organic C), C availability index (BR: SIR), particulate organic matter C, dissolved organic C, mineral N (i.e., NH4 and NO3), microbial biomass N, particulate organic matter N and dissolved organic N were decreased in the continuous grazing site. Thus, we concluded that continuous grazing might depress soil C and N microbial activity, but woody rangeland could improve soil quality.

Protein and carbohydrate fractionation of Jiggs Bermudagrass in different seasons and under intermittent grazing by Holstein cows

Jiggs bermudagrass has presented competitive production potential over other forages. However, there is a lack of information about the nutritional value of this forage with important relevance in ruminant nutrition. This study aimed to evaluate the protein and carbohydrate fractionation of Jiggs bermudagrass in different seasons of the year under intermittent grazing by Holstein cows. The experiment was conducted during one year in a completely randomized design with nine replications and treatments consisted of the effect of four seasons: fall, winter, spring and summer. The results showed that there were seasonal variations in the fractions of proteins and carbohydrate, with the exception of the protein fraction B3. The better climatic conditions in spring and summer contributed to an increase in the protein fraction A and carbohydrate A+B1. The winter had a greater fraction C of protein and carbohydrate, reflecting the nutritive value of the forage. The use of irrigation during fall and winter had a positive effect on nitrogen fractions B1 and B2 and on non-fiber carbohydrates.

Feral fuchsia eating: Long-term decline of a palatable shrub in grazed rangelands

Palatable shrubs and trees in rangelands are vulnerable to grazing impacts, with local extinctions and declines documented. However, population trends are difficult to detect due to longevity of individuals and poor understanding of regeneration. We investigated the demography and conservation status of the Grey Range fuchsia (Eremophila stenophylla Chinnock), a geographically restricted and palatable shrub endemic to south-west Queensland. We documented 28 populations over 30,400 km2, with an estimated total population size of 17,000 individuals. Seedling recruitment is rare and seedlings were observed at six populations, all with low or intermittent grazing pressure. In contrast, vegetative recruits were recorded at 19 populations and comprised at least 28% of plants measured. Resprouting confers some resilience to individuals, although repeated browsing restricts plant growth, limiting flowering and fruiting. Consistently heavily grazed populations also contain fewer plants. Although Eremophila stenophylla is secure in numerous populations with low grazing pressure, it qualifies as Vulnerable under IUCN Red List criteria due to past and ongoing decline at more than half of its populations. Grazing relief is necessary to ensure the long-term persistence of these populations. We predict that similar trajectories apply to other semi-arid shrubs, and research is required to inform grazing management to avert local extinctions.

Manipulating the ecosystem enables management of soilborne pathogen complexes in annual legume forage systems

Studies were undertaken to examine the potential for manipulating the ecosystem by altering forage species composition, intensity of grazing or by adding Rhizobium, to enhance productivity of subterranean clover (Trifolium subterraneum) forages affected by the soilborne pathogens Pythium irregulare and Rhizoctonia solani. Levels of tap and lateral root disease on clover and its productivity were differentially and significantly affected by the relative proportions of clover to annual ryegrass (Lolium rigidum). In the presence of P. irregulare, both tap and lateral root disease decreased as percentage clover composition increased (R2 = 0.58, 0.59, respectively); there was no such significant effect in the presence of R. solani (R2 = 0.08, 0.18, respectively). Increasing and maintaining high clover content in forage offers a means to both reduce root disease and increase productivity and forage legume stand persistence. With simulated grazing studies, continuous (i.e. intensive) grazing in the presence of P. irregulare resulted in the most severe tap and lateral root disease, poorest nodulation and smallest roots and shoots compared with intermittent grazing. Hence, reducing grazing intensity also offers potential for significantly increasing productivity of root‐rot‐affected clover forage. For Rhizobium studies, nodulation was reduced in the presence of P. irregulare or R. solani; the extent of this was dependent upon which pathogen and the clover variety. Overall, these different studies highlight significant potential for manipulating the ecosystem to better manage soilborne pathogen complexes and improve productivity and persistence in annual legume forage systems adversely affected by soilborne oomycete and fungal pathogens.

English

The objective of this study was to evaluate the effect of two defoliation intervals on the morphological characteristics of the experimental group. Chemical composition characteristics of a Tanzania grass pasture (Panicum maximum) and the performance of crossbred cows on intermittent grazing were examined. The digestibility of the dry matter, the digestibility of the organic matter fibrous, the voluntary dry matter intake and the voluntary intake of the organic matter fibrous were also determined. Milk production of cows was obtained in two daily milks. The levels of fat, protein, lactose, liquid energy and total milk solids were also quantified. The treatments consisted of evaluations of two pasture management strategies: 95% interception of photosynthetically active radiation and pasture managed with 30 days of defoliation interval. The study thus revealed that management causes differences in the chemical composition of Tanzania grass, but does not allow individual productive increases. Management based on IL 95% leads to higher milk production per unit area. Key words: Cattle dung, environmental sustainability, overcoming dormancy, rumen. &nbsp

Production of Jiggs bermudagrass and the impact of quality milk production and quality of Holstein dairy cows under an intermittent grazing system

Dairy production plays a fundamental role in the Brazilian economy and high-quality forage is necessary for ruminants to produce satisfactory milk levels. The aim of the present study was to evaluate the production and quality of Jiggs bermudagrass and its effects on the production and quality parameters of milk from Holstein cows under an intermittent grazing system throughout the year. The experiment was conducted in a randomized design with the four seasons as treatments, replicated five times. The season had a significant effect on the production and nutritional parameters of Jiggs bermudagrass with the highest total dry matter production observed during summer, followed by spring and fall. The neutral detergent fiber and acid detergent fiber contents were significantly higher in winter. The in vitro dry matter digestibility was significantly higher in summer, spring, and fall. Jiggs bermudagrass is a promising forage for the enhancement of milk production under intermittent stocking. However, its effects vary seasonally which exerts a greater influence during the winter, even with irrigation, because it directly affects the milk production and quality. The correlation results demonstrated the importance of better quality forage for increasing milk production without compromising the levels of milk solids.

Increasing levels of supplementation for crossbred steers on pasture during the dry period of the year.

The aim of this study was to evaluate the effect of increasing concentrate supplementation levels on the intake, nutrient digestibility, and performance of crossbred steers during the dry period of the year. The experiment was developed on Princesa do Mateiro farm, in the municipality of Ribeirão do Largo, located in the southwest region of Bahia State, Brazil. Forty uncastrated male crossbred (½ Holstein-Zebu) steers with an average body weight (BW) of 232.55 ± 24.97kg were distributed into four treatments in a completely randomized design with ten replicates. The animals were managed in an experimental area formed by Brachiaria brizantha cv. Marandu, in an intermittent grazing system. Treatments consisted of the following supplementation levels: 0.2% BW, with 60% crude protein (CP); 0.3% BW, with 40% CP; 0.4% BW, with 30% CP; and 0.5% BW, with 24% CP. The intakes of forage dry matter in kg/day and %BW and neutral detergent fiber corrected for ash and protein (NDFap) in %BW decreased linearly, whereas the intake of non-fibrous carbohydrates corrected for ash and protein in kg/day and average daily gain increased linearly. Therefore, the use of supplementation at 0.5% BW (24% crude protein) to provide gains of up to 0.500kg/day is recommended for grazing steers during the post-weaning period in the dry season of the year.

Production, Forage Quality, and Performance of Holstein Cows under Intermittent Grazing on Tifton 85

Tropical forage grasses compose the base diet of the Brazilian cattle herd due to their low production cost, high production potential, and good adaptation to various Brazilian ecosystems. In recent years, the search has intensified for alternatives that increase the yield in pasture milk production systems. Thus, the present study evaluated the production and quality of Tifton 85 grass in relation to the production parameters (e.g. greater leaf: stem ratio), and milk quality of Holstein cows in an intermittent grazing system during different seasons of the year. The experiment was conducted at the Córrego da Ponte Farm in Santa Helena de Goias, Goias, Brazil, from April 2014 to March 2015. The experiment used a completely randomized design with nine replicates and the four seasons (fall, winter, spring, and summer) as treatments. The Holstein cows had a live weight of 560±36.8 kg and averages four years of age. The grazing method used was a mob-stocking, with one day of grazing and 19 days of rest. The results showed that Tifton 85 was efficient regarding production parameters (total dry mass) and forage quality (IVDMD, NDF, ADF). The milk production was satisfactory during the fall, spring, and summer. The forage showed limited production during the winter, due the highest NDF, ADF levels and lower IVDMD (P &lt; 0.05), which was directly reflected in the milk yield, fat, protein and lactose (P &lt; 0.05). A reduction in the stocking rate or an increase in the number of paddocks is advisable during the winter to maximize milk production without compromising forage development. The correlation data showed the importance of consuming better-quality forage to increase milk production without compromising the levels of milk solids.

Maintaining post‐grazing sward height of Panicum maximum (cv. Mombaça) at 50 cm led to higher animal performance compared with post‐grazing height of 30 cm

AbstractIn swards of tall, tufted, tropical grasses like Mombaça guinea grass (Panicum maximum (Jacq.)), post‐grazing heights promote changes in sward structure, which influence animal performance. This study evaluated changes in sward structure in response to grazing management at two post‐grazing heights (30 and 50 cm), associated with 90 cm pre‐grazing height. Each treatment was allocated to experimental unit (1.5 ha) in three replicated blocks. Pastures were evaluated pre‐ and post‐grazing to estimate herbage mass, percentages of leaf (LP), stem (SP) and dead material (DP), and nutritive value (VN). Stocking rate was adjusted twice a week “using the put‐and‐take approach,” and animals were weighed every 28 days. Forage accumulation rate was greater for pasture managed at 30 cm (64.8 vs. 55.1 kg ha−1 day−1) than 50 cm. A greater number of days were required after grazing 30‐cm residual pasture to achieve the pre‐grazing target height, resulting in 25% decrease in number of grazing cycles compared with pastures managed at 50 cm. Regardless of post‐grazing height targets, SP and DP decreased, whereas LP and NV increased from soil level to top of canopy. Stocking rate was greater in pastures managed to 30 cm than in those managed to 50 cm residual height (4.7 vs. 3.4 AU ha−1). However, average daily gain was greater for 50 cm than for 30 cm post‐grazing height (795 vs. 590 g steer−1 day−1), resulting in a greater animal production per area (917 vs. 794 kg/ha of live weight). Thus, Mombaça guinea grass subject to intermittent grazing should be managed at 50 cm residual height.