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In grazing ecosystems, mature seeds fall directly to the soil to form the soil seed bank (SSB), or are ingested by grazing livestock to become part of the dung seed bank (DSB; i.e., seed circulation). Both the SSB and DSB form the basis for the natural regeneration of vegetation. However, little is known about the relationships between the SSB, DSB, and aboveground vegetation (AGV) community under different stocking rates (SRs). This study investigated the relationships between the SSB, seeds in Tan sheep (Ovis aries) dung, and AGV at different SRs (0, 2.7, 5.3, and 8.7 sheep ha–1) in a semiarid region of the Loess Plateau in China. We found that Tan sheep grazing increased the species richness heterogeneity of grassland vegetation, and negatively influenced the density of AGV. Under natural conditions, 17 species from soil‐borne seeds and 10 species from Tan sheep dung germinated. There was low species similarity between the soil and DSBs and AGV. Sheep SR and the seed banks (soil and dung) were negatively correlated with AGV. Seeds are cycled from herbage to livestock to soil during cold season grazing; the seasonal nature of this seed dispersal is an adaptation to harsh, semiarid environments. Increased seed bank diversity under sheep grazing facilitates grassland regeneration on the Loess Plateau, similarly to other semiarid regions globally., Mature seeds can fall directly onto the soil to form the soil seed bank or become part of the dung seed bank through livestock grazing. Seeds in the feces eventually are incorporated into the soil, contributing to the soil seed bank. Seed cycling was depressed at higher grazing intensities. Sheep grazing disturbance increases the diversity of seed banks and assists in the propagation and regeneration of vegetation on the Loess Plateau and in other semi‐arid regions of the world.

Inadequate information about the long-term effects of grazing strategies on native grass production and animal growth poses limitations to sustainable management of beef cattle. A 20-year simulation study was conducted using the Sustainable Grazing Systems model to analyse implications of different stocking rates (SRs) and simple rotational grazing systems (SRGSs) for rangeland-based Brahman steers. Simulations included three SRGSs (two, three and four paddocks per herd) and four SRs that were compared for their effects on grass production, dry matter intake (DMI) and live weight gain (LWG). Stocking rates included a recommended SR of 10 ha livestock unit (LU)−1, 30% high (7 ha LU−1) and, 50% and 100% low (15 and 20 ha LU−1), respectively, SR. Overall, there were no observable differences in the long-term response of grass production and DMI to all treatments for SRGS and SR. In addition, effects of SRGSs on animal production were almost similar across treatments in short and long timeframes, but differential responses of LWG to SRs were more pronounced regardless of time. These findings provide a useful criterion for choosing effective SRs to achieve sustained grass and animal production with lowest risk.

Four different salinities (0, 13, 26, and 39 ppt) were tested to evaluate their effects on growth performance, feed utilization, carcass composition, and chromatic deformity of the hybrid red tilapia (Oreochromis niloticus and O. mossambicus). 204 samples of 97 days post-hatch fingerlings red tilapia were stocked in a glass aquarium filled with 80 liters of water at a stocking rate of 17 fingerlings/ aquarium (0.21fingerlings/L), with an average initial weight of 12.48±0.04 g/fish and three replicates for each treatment. Fingerlings were fed on the experimental diet containing 30.3% protein at a 5% feeding rate, and re-adjusted periodically every10 days. The experimental period was 42 days. The results revealed that the final weight, weight gain, ADG, and SGR values increased significantly (P≤0.05) at the salinity level of 26 ppt, followed by 13 ppt salinity level. The survival % showed that all salinity levels had a high percentage without recording significant differences (P>0.05) between treatments. The best FCR was recorded in a salinity level of 26 ppt with significant differences (P≤0.05) between the treatments. The highest values of PER, PPV, and energy gain were recorded at 26 ppt. Salinity levels significantly influenced dry matter, protein, ether extract, ash, and carcass energy under the investigated salinities. The lowest percent of the chromatic deformity was achieved at salinity 26 ppt. It could be concluded that cultivating hybrid red tilapia in salinity levels between 13 and 26 ppt would significantly improve growth performance and feed utilization and reduce the percentage of fish with chromatic deformity as well.

Objective This experiment was conducted to evaluate performance (using 5 yr of data reported here, and the additional 5 yr of results previously) and economic return (10 yr) of steers grazing smooth bromegrass pastures over 10 consecutive years to determine profitability and pasture longevity under 3 management strategies. Materials and Methods Treatments consisted of cattle (n = 450; 45/yr) grazing smooth bromegrass pastures (n = 9/yr) fertilized with 90 kg of N/ha (FERT), unfertilized pastures stocked with cattle that received distillers grains plus solubles (DGS) daily at 0.6% of BW (SUPP), and unfertilized pastures stocked with cattle that received no supplement (control, CON). A randomized complete block design was used each year with 3 treatments present in each of 3 pasture blocks and treatments maintained in the same areas for all 10 yr. Results and Discussion Cattle supplemented daily with DGS had greater ADG (1.19 kg/d; P Implications and Applications Fluctuating market conditions and changes of input costs affect the overall profitability of treatments and relative differences. In this scenario, holding all prices constant except DGS, price of DGS would have to increase by 20% (increase of $43.29/908 kg) in order for applying N fertilizer to pastures (FERT) or increasing stocking rate (CON) to be more profitable than supplementing cattle with distillers grains (SUPP).

Seasonality in tropical forage production is common in tropical and subtropical regions and should be identified for decision making on the stocking rate for each period. This study aimed to evalua...

Mixed pastures of Rhodes grass (Chloris gayana cv. Callide) and Stylo (Stylosanthes guianensis cv. Cook) were evaluated at fi.ve slacking rate, 12, 18, 2 4, 3 0 and 36 rams/ha over five grazing periods at Shika, Nigeria. The pastures were continuously grazed for 154 to 210 days beginning from late rainy into dry season (August to April). Dry matter yields of stem, leaf stem + leaf of C gayana, green material and total herbage declined (P

Objective The objective was to study the effect of stocking rate on animal performance and the performance of Nelson annual ryegrass. Materials and Methods In 3 consecutive years, steers were continuously stocked under 4 different stocking rates. Cattle were weighed and ryegrass samples were obtained fortnightly. Forage mass, nutritive value, grazing days, ADG, production per area, DMI, and forage allowance were determined. Mixed models were used to determine the effect of treatment and year, and regression analyses were conducted for forage data. Results and Discussion Increases in stocking rate decreased (P Implications and Applications Differences in animal production and nutritive value of annual ryegrass due to increasing stocking rates were obtained, and year was an important factor influencing the final data. The experimental evaluation of stocking rates, as with other grazing management techniques, is very dependent on weather and production site.

On The Ground • No research involving the comparative evaluation of grazing methods has been performed in South Texas at an operational scale. • We report initial findings from a large-scale demonstration project involving two cattle stocking rates and two grazing methods; our focus was on forage standing crop and forage utilization responses. • Erratic, but typical, rainfall patterns and resulting forage production proved our stocking rates (though realistic for this region) to be unsustainable over the long term, regardless of grazing method. • The “Wild Horse Desert” is a harsh but resilient environment following periods of above average rainfall.

A ten weeks feeding trial was conducted to evaluate the effect of bitter kola on the growth performance, hematology and sperm quality of juvenile African catfish (Clarias gariepinus). Six diets of 40% crude protein were formulated with different inclusion levels of bitter kola seed meal. Diet1 (control) has 0g/kg of the seed meal while Diet2, Diet3, Diet4, Diet5 and Diet6 contained 50g/kg, 100g/kg, 150g/kg, 200g/kg, 250g/kg bitter kola seed meal(BKSM) respectively. A total of sixty (60) healthy juvenile Clarias gariepinus were randomly selected and distributed in into twelve (12) plastic tanks at stocking rate of five (5) fish per tank and the experiment was replicated twice. Fish were fed twice a day, morning (8;00hr) and evening (17:00hrs) for ten weeks, At the end of the feeding period, blood samples were collected from the fish samples for haematological analysis and growth rate were determined.

Grazing goats have potential for use in managing abandoned fields. However, it is unclear how long-term grazing affects goats as a result of vegetational changes in abandoned fields. This study aimed to assess the dynamics of vegetation quality and quantity and the nutritional status of goats for five years in an abandoned field at different stocking rates: high stocking rate (HS: 30–33 goats/ha) and low stocking rate (LS: 14 goats/ha). In five years, the dominant plant species changed from bamboo (Phyllostachys edulis) to tufted grass species at the HS, whereas dwarf bamboo (Pleioblastus argenteostriatus) dominated throughout the five years at the LS. The annual plant biomass at both stocking rates was similar and varied from year to year. Crude protein content in the goats' diet did not show any seasonal or annual trend regardless of the stocking rate. Neutral detergent fiber content in the HS diet did not show any seasonal or annual trend; however, that in the LS diet linearly increased with the grazing year. The dry matter (DM) intake for goats at the LS decreased linearly with the grazing year (p < 0.05), whereas that for goats at the HS did not show any trend. The DM digestibility was higher for goats at the HS than for goats at the LS (p < 0.05). Serum parameters did not show a negative nutritional status of the goats over the study years. Annual daily gain was positive throughout the grazing years regardless of the stocking rate. Consequently, within the stocking rate range studied here, long-term goat grazing changes the quality of vegetation in an abandoned field; however, goats can maintain their nutritional status and body weight for five years. Thus, goat grazing is a feasible way to control abandoned vegetation over the long term.

The expression production potential represents the maximum amount of products that can be obtained per unit area. However, what is the maximum amount of product that can be obtained in a pasture area? To answer this question, it is necessary to understand the factors related to forage accumulation, grazing efficiency, chemical composition of the forage plant, forage intake and nutritional requirements of animals, management, genetics, and management of the production system. The average annual productivity of beef cattle in Brazil is approximately 120 kg of body weight (approximately 60 kg of carcass) per hectare. This index is below the parameters reported in the literature. Adequate management of pastures with tropical forages usually provides a stocking rate above one animal unit (450 kg) per hectare. The increase in the stocking rate, combined with high individual body weight gain, provides high productivity, which may exceed 1260 kg of body weight (approximately 630 of carcass) per hectare per year. The production of beef cattle in tropical pastures has a high response potential with regard to the adoption of technologies to increase productivity indices. Resumo O termo potencial de produção representa a quantidade máxima de produto que seria possível se obter em uma determinada área. Mas qual é o potencial de produção da bovinocultura de corte em pastagens tropicais? Para responder esta pergunta, é necessário compreender os fatores relacionados ao acúmulo de forragem, eficiência de pastejo, composição química da planta forrageira, consumo de forragem e requerimento nutricional dos animais para um dado desempenho, manejo, genética e gestão do sistema de produção. A produtividade média anual da pecuária de corte no Brasil está em torno de 120 kg de peso corporal (aproximadamente 60 kg de carcaça) por hectare. Este índice está bem abaixo de resultados reportados na literatura. O manejo adequado de pastagens com forrageiras tropicais normalmente proporciona taxa de lotação acima de uma unidade animal (UA, 450 kg) por hectare. O aumento na taxa de lotação, combinado com elevado ganho de peso proporcionam alta produtividade, podendo ultrapassar 1260 kg de peso corporal (aproximadamente 630 kg de carcaça) anuais por hectare. A produção de bovinos de corte em pastagens tropicais possui alto potencial de resposta quanto a adoção de tecnologias para incremento nos índices de produtividade.

The need to address wildlife conservation outside of protected areas has become more urgent than ever before to meet environmental and socio‐economic goals. However, there is limited knowledge about how woody plants respond to herbivory within landscapes shared by wildlife and domestic herbivores in African savanna, thus management decisions might be based on inaccurate information and ultimately be ineffective. We compared woody vegetation dynamics between two adjacent ranches with different management objectives and subjected to varying levels of herbivory by both wildlife and domesticated mammals using 421 square plots of 400 m2 nested on three transects, each 3 km long and purposively selected to minimize bio‐physical differences. Both species and structural diversity were significantly higher (p

The South African National Research Foundation (SFH150718127604), AgriProtein Technologies, South Africa and a University of Pretoria Research Development Programme grant.

Zonguldak ilinde uzun süre bir (BTO; sığır) veya birden fazla (karışık) hayvan türü (KTO; sığır, koyun ve keçi) ile farklı seviyelerde otlatma baskısına maruz kalan meraların değerlendirilmesi için 2015 ve 2016 yıllarında iki çalışma yapılmıştır. Otlatma baskısı muameleleri şu şekilde oluşturulmuştur: büyük baş hayvan birimi (BBHB) ha-1

New highly productive guineagrass (Megathyrsus maximus syn. Panicum maximum) cultivars have been released in Brazil and grazing trials are necessary to evaluate their carrying capacity and forage quality. The objective of this study was to evaluate the liveweight gains of young Nellore bulls grazing 3 guineagrass cultivars under rotational stocking. The experiment was carried out in Planaltina (Federal District, Brazil) during a single rainy (November‒April) and dry (May‒August) season. Treatments were Massai (control), BRS Tamani and BRS Zuri cultivars. Zuri and Tamani pastures provided greater average daily liveweight gains (ADG) (0.38 and 0.42 kg/head, respectively) over the experimental period than Massai (0.28 kg/head). For all cultivars liveweight gains decreased markedly from May onwards at the beginning of the dry season. Nevertheless, bulls grazing Tamani and Zuri pastures still gained 0.20 kg/hd/d until late August, while those on Massai pastures gained only 0.08 kg/hd/d. The differences in ADGs can be explained to some extent by differences in quality of available forage. In vitro dry matter digestibility of plucked samples of Massai was 555 g/kg, compared with 621 g/kg for Tamani and 590 g/kg for Zuri. Crude protein concentration in plucked samples was also greater for Tamani and Zuri (71.9 and 74.2 g/kg, respectively) than for Massai (62.2 g/kg). As feed wastage was particularly high in Massai, further studies are needed to verify if higher stocking rates during the wet season could result in greater production of live weight per ha on this cultivar, assuming that ADG does not decrease further with the increased stocking rate. Resumen En Brasil se han liberado nuevos cultivares del pasto guinea (Megathyrsus maximus sin. Panicum maximum) altamente productivos y es necesario evaluar su capacidad de carga y la calidad del forraje en condiciones de pastoreo. El objetivo de este estudio fue evaluar las ganancias de peso vivo de toretes Nellore en tres pasturas de guinea bajo pastoreo rotacional. El experimento se llevó a cabo en Planaltina (Distrito Federal), Brasil, durante una temporada lluviosa (noviembre‒abril) y una temporada seca (mayo‒agosto). Los tratamientos fueron los cultivares Massai (testigo), BRS Tamani y BRS Zuri. Zuri y Tamani proporcionaron mayores ganancias de peso vivo diarias (0.38 y 0.42 kg/animal, respectivamente) durante el período experimental que Massai (0.28 kg/animal). Para los tres cultivares, las ganancias de peso vivo animal disminuyeron notablemente a partir de mayo (comienzo de la estación seca). No obstante, los toretes pastoreando Tamani y Zuri ganaron 0.20 kg/animal/día hasta fines de agosto, mientras que los animales en Massai ganaron solo 0.08 kg/animal/día. Estos resultados se pueden explicar por las diferencias en la calidad del forraje disponible, determinada con base en un muestreo de simulación de pastoreo (‘hand-plucking’). La digestibilidad in vitro de la materia seca de Massai fue de 555 g/kg, en comparación con 621 g/kg para Tamani y 590 g/kg para Zuri. La concentración de proteína cruda también fue mayor para Tamani y Zuri (71.9 y 74.2 g/kg, respectivamente) que para Massai (62.2 g/kg). Como el desperdicio de forraje fue particularmente alto en Massai, se necesitan más estudios para determinar si en este cultivar eventuales cargas animal más altas durante la temporada lluviosa podrían resultar en una mayor producción de peso vivo por hectárea sin afectar la ganancia de peso diaria por animal.

Triplet-bearing ewes and their lambs have the potential to improve flock productivity however, the lack of robust information on optimal nutrition and management is limiting their performance. In c...

Teak is an important forest plantation species in Lao PDR (Laos), that has been planted extensively by smallholders, supplying domestic industries and international markets. There have been significant advances in the intensive silvicultural management of teak focused on the production of high-quality timber. Laos is not an exception. With support from the Australian Centre for International Agricultural Research, there have been advances in the understanding and knowledge of appropriate management practices for smallholder teak, as well as development of supporting technologies (i.e. ex situ conservation, genetic improvement, growth models, thinning and pruning prescriptions, and agroforestry systems). This paper summarises published information on the silviculture and management of teak, including improvement of genetic resources, stocking rate, thinning and agroforestry systems used in Asia, Africa, Latin America and Oceania, and relates this to the current situation in northern Laos. The challenge is to now transfer this knowledge to the teak smallholders, professionals, educators and policy decision makers of Laos.

Higher stocking rates of lambing ewes have been associated with poorer ewe-lamb behaviour and lamb survival. This study tested the hypothesis that increasing the mob size and stocking rate of lambi...

Limited research has suggested that higher lambing densities increase interference from foreign ewes at lambing which disrupts the ewe-lamb bond and compromises lamb survival. This may be particularly evident in mobs of twin-bearing ewes compared to single-bearing ewes because a greater number of lambs are born per day. Therefore, we hypothesised that; (i) decreasing the mob size of ewes at lambing has a greater impact on the survival of twin-born lambs than single-born lambs; (ii) the relationship between mob size and lamb survival can be explained by differences in the rate of interaction with foreign ewes and lambs at lambing; and (iii) ewes will utilise a limited area of the paddock at lambing and thus lambing density will be defined by the distribution of ewes in the paddock rather than the paddock area. Merino ewes were allocated into a 2×2 factorial combination of ewe pregnancy status (single- or twin-bearing) and mob size (high (n=130 ewes) or low (n=50 ewes)) on day 140 from the start of joining. Each treatment had two replicates excepting the low mob size for twins which had a third replicate. Ewes lambed at a stocking rate of 11 ewes/ha. Feed-on-offer during lambing exceeded 2400 kg dry matter (DM)/ha. Ewe-lamb behaviour was observed and dead lambs were autopsied over 11 days during the peak of lambing. The distribution of ewes in each paddock was recorded every 2 h during daylight hours by counting the number of ewes occupying 2500 m2 grids. The proportion of ewes and their newborn progeny which interacted with foreign ewes at lambing did not differ between the high and low mob sizes for single- (24.9% v. 20.8%) or twin-bearing ewes (14.3% v. 19.6%; P=0.74). Similarly, interaction with foreign lambs did not differ between the high and low mob sizes for single- (14.5% v. 25.2%) and twin-bearing ewes (34.5% v. 26.4%; P=0.44). The distribution of ewes within the paddock did not differ between treatments (P=0.95). On average, single-bearing ewes which lambed at the high and low mob sizes occupied 34% and 36% of the paddock during daylight hours, and the corresponding values for twin-bearing ewes were 40% and 43%. Survival of twin-born lambs was lower than single-born lambs (75.3% v. 87.9%; Plt;0.01), however, lamb survival was not influenced by mob size regardless of birth type. These results suggest that higher mob sizes may not compromise lamb survival when feed-on-offer during lambing exceeds 2400 kg DM/ha.

Background Strongylid nematode infections may negatively affect both animal health and welfare, with deleterious consequences for livestock productivity. Many farmers in recent decades have relied on anthelmintics as the sole strategy of control, but the intensive use of these chemotherapeutics has led to the development of anthelmintic resistance (AR). Knowledge of both the efficacy of anthelmintics and factors promoting AR are essential to effectively control nematode infections, but no information on these topics for goats in the Czech Republic (CR) is available. This survey aimed to determine the occurrence of AR at Czech goat farms and to identify risk factors for the development of AR. A total of 24 herds of dairy goats across the CR were evaluated using in vitro tests for detecting AR, and a questionnaire survey was carried out to evaluate factors associated with AR. Results Resistance against benzimidazoles was confirmed at 18 (75%) farms, and the level of resistance was high in four (22%) of the affected herds based on the egg hatch test. Ivermectin-resistant nematodes were detected in 13 (54%) herds using the larval development test; Teladorsagia/Trichostrongylus and Haemonchus were the predominant types of resistant larvae. Eight (62%) of the affected herds were evaluated as highly resistant to ivermectin. Eleven (46%) of the herds were resistant to both benzimidazoles and ivermectin. This report is the first on dual AR in the CR. A univariate logistic regression analysis indicated that a high stocking rate and farmer inexperience were significantly associated with ivermectin and benzimidazole resistance, respectively. Conclusions The results of our survey suggest that AR is widespread amongst herds of dairy goats in the CR, likely due to inappropriate practices of pasture and health management. AR may be an issue for expanding dairy-goat production in the CR in the near future unless both veterinary practitioners and farmers widely adopt strategies to prevent the development of AR.

In the Desert Grassland, second and subsequent defoliations on perennial grasses during the active growing season can have substantial impacts on grass recovery and reproduction following herbivory. Land managers implement tactics to avoid multiple defoliations on plants by way of rotational grazing, reduced stocking rates, and/or reduced time spent within a given pasture. We explored frequency and rate of defoliation by cattle on perennial bunchgrasses within an 11-day grazing period in three pastures including distance to water (300 and 600 m) and plant height to determine their influence on animal diet selection. Results indicate that 32% of all marked plants were defoliated by cattle and only 5% of defoliated plants were defoliated a second time by day 10 of the grazing period. Defoliation patterns in the studied pastures did not differ between two distances from water, or in relation to plant height. However, at the second defoliation cattle grazed plants that were shorter than at the first defoliation suggesting a selection for high quality re-growth over larger forage on offer. The results of this study show that a 10-day grazing period during the growing season of the Desert Grassland is an effective strategy to avoid second defoliations on individual perennial grass plants while maintaining sufficient forage for use during the dormant winter grazing season.

Correct pasture management associated with the adjustment of grazing intensity determines pasture persistence and the level of production per animal and per land area. The objective of this review was to examine the effect of grazing intensity in tropical pastures on the performance and productivity of beef cattle by a meta-analytical approach. The review followed a protocol developed and tested based on the PICOS strategy to formulate the guiding question: population (beef cattle), intervention (high grazing intensities), comparison (low grazing intensities), outcome (animal performance and productivity), and study design (experimental). Data were collected from papers published in the electronic databases of SCOPUS (Elsevier), Web of Science (Main collection), SpringerLink, Wiley Online Library, and Science Direct (Elsevier) by a single cross-reference search. The selected studies were considered relevant when they: (1) were primary research published in the format of a research article; (2) included grazing intensities as a management strategy; and (3) evaluated average daily gain (ADG, kg/animal per day), stocking rates (SR, animal unit (AU)/ha; AU = 450 kg), and weight gain per area (WGH, kg/ha). Thirteen manuscripts were selected due to their methodological strength for data extraction. The means under continuous stocking were 0.67 kg/animal per day for ADG, 518.12 kg/ha for WGH, and 4.19 AU/ha for SR. Under intermittent stocking, the means were 0.62 kg/animal per day for ADG, 980.18 kg/ha for WGH, and 5.10 AU/ha for SR. In tropical forages, the heights of 20 to 40 cm for pastures under continuous stocking and the defoliation intensities of 40 to 50% for those under intermittent stocking result in greater individual performance and animal productivity per land area.

This study investigated if there is any confounding effect of stocking rate on the use of internal markers to determine and predict the dietary ingredient composition, dry matter intake (DMI) and digestibility of diets consumed by sheep. Fifteen sheep were randomly allocated to stocking rate treatments of one (SR1), two (SR2), four (SR4) and eight (SR8) sheep per pen (space allowance: 31.04 m2, 15.52 m2, 7.76 m2 and 3.88 m2 per sheep, respectively) and fed ad libitum maize stover, sorghum stover and veld hay by supplying 110% of previous day&rsquo, s intake. Sheep were rotated across the treatments in four periods of 10 days. The proportion of feeds selected and total DMI were similar across all stocking rate treatments. However, diets selected by sheep in SR2 had the highest digestibility compared to other treatments. The prediction of the effective degradability of dry matter using acid detergent fibre content achieved an accuracy of 84.6%. A combination of crude protein and neutral detergent fibre contents achieved 63% accuracy in the prediction of the rate of degradation of feeds. The use of acid insoluble ash (AIA) as an internal marker to predict nutrient intake, digestibility, DMI and dietary ingredient intake accounted for 84.3%, 81.2%, 53.0% and 64.1% of the variation, respectively. The predictions of dietary feed proportions and nutrient quality selected obtained with least squares procedure using a combination of modified acid detergent fibre (MADF), acid detergent lignin (ADL) and AIA accounted for 81.0% and 72.4% of the variation, respectively. In conclusion, regardless of the different stocking rate tested in this study, a combination of MADF, ADL and AIA as internal markers can be used to estimate diet and nutrient selection by sheep using the least squares procedure. Hence, these markers can be used to predict ingredient composition of diet, diet and nutrient selection, nutrient intake and digestibility in free ranging animals.

This study was conducted to determine the effect of two different levels of supplementary feed and two different stocking rates on the production of g razing ostriches. One hundred and seventy ostriches were randomly allocated to four groups and kept on irrig ated lucerne pasture with or without supplementary feed from approximately 58 kg to a target weight of 95 k g. The ostriches rotationally grazed lucerne pastur e at one of two stocking rates, i.e. 15 birds/ha or 10 b irds/ha and were fed one of two levels of supplemen t i.e. 0 g or 800 g feed/d formulated according to the nutrien t requirements of the relevant group of birds. Data were analyzed by ANOVA. There was no interaction between the supplementary feed and stocking rate regarding mean live weight at 54 weeks of age and feed conversion ration (FCR). Data were provided as the two ma in effects of level of supplementation and stocking ra te. Significant differences in mean live weight at 54 weeks of age and FCR of the birds were observed between t he different levels of supplementary feed. The parameters measured for the two different stocking rates used in this study (10 birds/ha vs . 15 birds/ha) did not differ from each other and did not influence ei ther mean live weight at 54 weeks of age, average d aily gain (ADG) or FCR. The two groups which received 800 g supplementary feed/d reached slaughter weight (95 kg) within the set of 54 weeks of grazing for t he trial, while the two groups which received no supplementary feed did not achieve slaughter weight by 54 weeks on the pasture. Ostriches receiving supplementation of 800 g/bird/day had significantly better FCR’s than birds receiving no supplementati on. There was a significant interaction between level o f supplementary feed and stocking rate regarding ADG of the birds. As stocking rate increased, average dail y gains of birds receiving no supplementary feed de clined. This study indicates that ostriches being kept on g razing and receiving supplementary feed will exhibi t improved and faster growth rates than ostriches whi ch only have access to grazing and receive no supplementary feed.

The objective of this study was to evaluate the morphogenetic traits and chemical composition of Tanzania grass using a fixed rest period or according to light interception at 95%. The treatments consisted of evaluations of two Tanzania-grass pasture-management strategies: (1) LI95 - animals entered the paddocks when the pasture reached 95% of light interception (LI), with three days of paddock occupation; and (2) FR - the pasture was managed with a defoliation interval (DI) of 30 days, and three days of paddock occupation. The experimental area consisted of 4 ha, with 22 paddocks per treatments. Ten recently-calved cows were used per treatment in year 1, and eight cows were used per treatment in year 2. Sward height, forage mass, and morphological components and their chemical composition were evaluated. The management strategies used on the Tanzania grass pasture did not affect pasture mass or height in the pre- and post-grazing conditions, or the proportion of stems. However, the proportion of leaves was greater in the paddocks with 95% light interception. The crude protein content was higher in the paddocks with 95% light interception; the other nutrients were not affected. In conclusion, management adopting 95% light interception does not influence morphogenetic traits. Nevertheless, it promotes an increase in the crude protein content of grasses.

The objective of this study was to evaluate the effect of residual nitrogen (N) on pastures of Mombaça grass and its impact on pasture structure and the nutritive value and performance of beef cattle. The experiment analyzed randomized blocks subdivided into plots, with three replications. The research focused on a number of pastures having received three annual doses of N (100, 200 and 300 kg ha-1) from 2015 to 2017, with no N fertilization in 2018. The results indicated that pastures under residual effect of 300 kg ha-1 of N were characterized by higher (P0.05) on the pasture nutritive value and average daily gain (0.490 kg day-1). The stocking rate was higher (P

Commercial practice in poultry production management has been susceptible to increased problems, driven by concerns about safety of food and animal welfare. Thus, the main proposal of the present study was to evaluate the influence of different stocking densities on performance, blood, and carcass traits of Pekin ducklings reared on two different floor types (wood shaving litter, WSL or plastic slatted floor, PLS). A total of 450 one-day-old ducklings were randomly allocated into six equal experimental groups stocking density (nine, 15 and 21 birds/m2 during the first 14 d and three, five and seven birds/m2 until 49 days) reared on two floor types (WSL and PLS), five replicate pens each. Increased stocking density reduced body weight (BW), weight gain (WG), and feed conversion ratio (FCR) values and increased feed intake (FI) in both floor types at 14 days old. At 49 days old, reared ducklings on PLS type verified higher BW and WG and reduced FCR values. Moreover, increasing stocking density in both floor types significantly reduced the breast, thigh, and left fillet percentages. Conversely, reared birds floored on PLS system decreased the triglycerides (TG) and increased the total cholesterol (TC) serum content. Furthermore, the meat contents of TG and TC were decreased in birds reared on higher stocking density but not affected by floor type. Further, serum antioxidant indices were reduced in PLS birds on low stocking densities. In conclusion, housing Pekin ducklings on PLS improved their growth performance, carcass traits, meat cholesterol, and antioxidant status, particularly at stocking density of three and five birds/m2.

Ground cover maintenance and nutrients management are key elements to reduce the environmental impact of outdoor swine production. The objective of this study was to determine the effects of sows-gilts stocking rates on vegetative ground cover and soil nutrient concentrations in rotationally stocked bermudagrass (Cynodon dactylon L. Pers) pastures. Three stocking rates (10, 15 and 25 sows-gilts ha&minus, 1) were compared during three 8-week grazing periods. Increasing the stocking rate from 10 to 25 sows-gilts ha&minus, 1 decreased the ground cover of the paddocks from 65 to 48%, and increased soil nutrient concentrations (ammonium 47%, nitrate 129%, phosphorus 53%, zinc 84%, and copper 29%).

Stocking rate is a fundamental management factor that has major impacts on animal performance, profitability, and long-term sustainability of native range ecosystems. This research was conducted to determine the effects of stocking rate on performance and economics of growing steers grazing a mixed-grass prairie on a rolling upland red shale ecological site at the Marvin Klemme Range Research Station (35° 25′ N 99° 3′ W). The recommended sustainable stocking rate at this location is suggested to be 25 animal unit days (AUD)/ha. Steers [n = 836, initial body weight (BW) ± SD = 216 ± 11.7 kg] grazed at seven stocking rates ranging from 4.13 ha/steer to 1.83 ha/steer over a 7-yr period, from 1990 to 1996, with year considered the random replication. During the experimental period, overall climatic conditions were favorable for forage production with average growing season precipitation of 118% of the long-term average over the 7-yr experiment, and only 1 yr (1994 with only 57% of the long-term average) with growing season precipitation substantially less than the long-term average. Over the entire summer grazing season, average daily gain (ADG) decreased linearly (P < 0.01) with increasing stocking rate, such that for each additional hectare available per steer ADG increased by 0.05 kg/d (R2 = 0.88). Contrary to ADG, BW gain per hectare over the grazing season increased linearly (P < 0.01) with increasing stocking rate, as stocking rate increased from 4.13 ha/steer to 1.83 ha/steer BW gain per hectare doubled from 33.1 kg/ha to 66.8 kg/ha, respectively. With land costs included in the economic analysis, net return per hectare increased linearly (P < 0.01) from $13 [U.S. Dollars [USD]) at the 4.13 ha/steer to $52/ha at the 1.83 ha/steer. For each additional hectare per steer, net return was reduced by $15.80 (USD)/steer and $15.70 (USD)/ha. In favorable climatic conditions, such as during this 7-yr experiment, economically optimal stocking rates can be more than doubled compared with the stocking rate recommended by the United States Department of Agriculture (USDA) Soil Conservation Service. Increasing stocking rates decrease individual animal performance but maximize BW gain per hectare, which leads to the increasing economic returns observed. Research is needed to determine the long-term implications of these stocking rates during unfavorable growing conditions and setting stocking rates based on seasonal weather patterns and extended weather outlook predictions.

The effects of supplement doses (0, 1, 2 and 3 kg ha-1 day-1) and grazing periods (1, 28, 59, 89 and 103 days) on the B. decumbens cv. Basilisk structure and cattle production in deferred pastures were evaluated. The design was a randomised complete block design with two replications. The sward height and the total forage and stem masses decreased with grazing period. The crude protein (8.12%) and in vitro organic matter digestibility (52.74%) were not affected by grazing period. The fibre content in neutral and acid detergent increased linearly with the grazing period. The average daily gain of cattle ranged from 0.419 to 1.019 kg animal-1 day-1; the stocking rate ranged from 2.7 to 3.9 animal unit ha-1; and the average gain per area ranged from 2.7 to 7.9 kg ha-1 day-1, with the maximum values obtained with the highest dose of concentrate. Concentrate supplementation increases cattle production in deferred pastures. During the use of deferred pasture in winter there are decreases in the quantity and quality of forage, as well as limitations in its structure. Resumo Foram avaliados os efeitos de doses de suplemento (0, 1, 2 e 3 kg animal-1 dia-1) e períodos de pastejos (1, 28, 59, 89 e 103 dias) sobre a estrutura da Brachiaria decumbens cv. Basilisk e a produção de bovinos em pastagens diferidas. O delineamento foi em blocos casualizados com duas repetições. A altura do pasto e as massas de forragem total e de colmo diminuíram com o período de pastejo. A proteína bruta (8,12%) e a digestibilidade in vitro da matéria orgânica (52,74%) não foram influenciadas pelo período de pastejo. Os teores de fibras em detergente neutro e ácido aumentaram linearmente com o período de pastejo. O ganho médio diário dos bovinos variou de 0,419 a 1,019 kg animal-1 dia-1; a taxa de lotação variou de 2,7 a 3,9 UA ha-1; e o ganho médio por área variou de 2,7 a 7,9 kg ha-1 dia-1, sendo os maiores valores obtidos com a dose mais alta de concentrado. A suplementação com concentrado aumenta a produção de bovinos em pastagens diferidas. Durante a utilização do pasto diferido no inverno há decréscimos na quantidade e na qualidade da forragem, bem como limitação em sua estrutura.

Cultivated pastures in southern China are being used to improve forage productivity and animal performance, but studies on grazing behaviour of goats in these cultivated pastures are still rare. In the current study, the grazing behaviour of Yunling black goats under low (5 goats/ha) and high (15 goats/ha) stocking rates (SRs) was evaluated. Data showed that the proportion of time goats spent on activities was: eating (0.59–0.87), ruminating (0.05–0.35), walking (0.03–0.06) and resting (0.01–0.03). Compared with low SR, goats spent more time eating and walking, and less time ruminating and resting under high SR. Goats had similar diet preferences under both SR and preferred to eat grasses (ryegrass and cocksfoot) more than a legume (white clover). The distribution of eating time on each forage species was more uniform under highv.low SR. Bites/step, bite weight and daily intake were greater under low than high SR. Results suggest that the SR affects grazing behaviour of goats on cultivated pasture, and identifying an optimal SR is critical for increasing bite weight and intake.

Foi estudado o desempenho de bezerras de corte em pastagem de azevem (Lolium multiflorum Lam.), com animais exclusivamente em pastejo ou recebendo farelo de arroz integral (FAI) em nivel de 0,8% do peso corporal associado ou nao a monensina. O FAI foi ministrado diariamente as 14 horas, e a monensina foi fornecida na quantidade de 200mg por animal. O metodo de pastejo foi continuo com numero variavel de animais. O delineamento experimental foi o inteiramente casualizado, com medidas repetidas no tempo, com tres tratamentos e tres repeticoes de area. As bezerras de corte foram submetidas a valores medios de massa de forragem (1490,0134,9kg ha-1 MS) e altura do dossel (100,68cm). As bezerras que receberam FAI independente do uso da monensina, apresentaram maior ganho diario, peso corporal, escore de condicao corporal e relacao peso corporal:altura. Em 112 dias de pastejo, as bezerras que receberam FAI com ou sem ionoforo, ganharam 28% do peso corporal em relacao ao peso adulto projetado. O uso de FAI associado ou nao a monensina nao expressou alteracao na area pelvica das bezerras, na taxa de lotacao e no ganho de peso por area.%%%%The productive and reproductive performance of beef heifers grazing Italian ryegrass (Lolium multiflorum Lam) were studied with animals exclusively on pasture or receiving 0.8% of body weight of rice bran plus monensin or not. The rice bran was given daily at 2 pm and the monensin was provided in the amount of 200mg per animal. The grazing method was continuous with variable number of animals. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The beef heifers were submitted to average values of forage mass (1490.0134.9kg ha-1 MS) and sward height (100.68cm). Beef heifers supplemented with rice bran plus monensin or not had higher daily gain, weight body, body condition score and body weight:height ratio. Beef heifers receiving rice bran with or without ionophore in 112 days of grazing gain 28% of body weight in relation to adult weight. The supplementation with rice bran to grazing animals no change in pelvic area, stocking rate and area weight gain.

This study was carried out to evaluate the effects of four levels of intensification of grazing systems: 1) degraded pasture - DP; 2) irrigated pasture with high stocking rate - IHS; 3) dryland pasture with high stocking rate - DHS; 4) dryland pasture with moderate stocking rate - DMS; on growth, muscle development and meat quality of Nellore steers (271±2.2kg of live body weight - BW; 15months old) during two consecutive periods (17 and 15months). The final BW, the average daily BW gain, the hot carcass weight and the dress percentage were greater (P

The cumulative effects of daily herbage allowance (DHA) restriction on pasture characteristics and the sustainability of pasture-based dairy systems were evaluated. Sixty-four dairy cows were randomly assigned to one of two grazing treatments (20 and 30 kg DM cow-1 day-1). Milk yield and pre- and post-grazing herbage mass were recorded for every grazing event. Botanical and chemical compositions of the pasture were evaluated. Low DHA increased the stocking rate by 0.7 cows ha-1 and consequently increased grazing efficiency from 41 to 47%. Daily herbage allowance restriction did not affect pasture characteristics or milk production per cow, but DHA restriction increased milk production per hectare (+27%). The results suggest that restriction on daily herbage allowance ensures a higher level of herbage utilization and milk output per ha than high DHA, without affecting pasture characteristics. Therefore, DHA might be a useful grazing management tool for improving the profitability and sustainability of grazing-based dairy systems.

The objective of this work was to evaluate the physical properties of a soil with a 'Tanzânia' grass (Megathyrsus maximus) pasture fertilized with mineral nitrogen or intercropped with the legume 'Campo Grande' (Stylosanthes spp.), and subjected to continuous grazing and variable stocking rate, in a three-year chronosequence. The treatments were: 'Tanzânia' grass and Stylosanthes; and 'Tanzânia' grass fertilized with 75, 150, and 225 kg ha-1 N per year. The experiment was carried out in an Oxisol, in a randomized complete block design with three replicates, in split plots divided according to time (first, second, and third experimental years). The following soil properties were assessed annually: soil bulk density, porosity in the soil macropore domain, soil water and air storage capacity, and soil penetration resistance. After three years, the highest animal stocking rate due to increased forage yield did not affect the soil physical conditions. The intercrop of 'Tanzânia' grass with the legume shows values of soil water and air storage capacity close to the ideal ones (0.66 and 0.34, respectively). After the second experimental year, there is a decrease in the penetration resistance values, which are inferior to the critical limit of 2,500 kPa. The intercropping of 'Tanzânia' grass with stylosanthes 'Campo Grande' can be a remarkable alternative for the maintenance and improvement of soil physical conditions. Resumo: O objetivo deste trabalho foi avaliar as propriedades físicas de um solo com pastagem de capim-tanzânia (Megathyrsus maximus) fertilizado com nitrogênio mineral ou consorciado com a leguminosa estilosantes 'Campo Grande' (Stylosanthes spp.), submetido a pastejo contínuo e à taxa de lotação variável, em uma cronossequência de três anos. Os tratamentos foram: capim-tanzânia e estilosantes; e capim-tanzânia adubado com 75, 150 e 225 kg ha-1 de N por ano. O experimento foi realizado em Latossolo Vermelho distrófico, em blocos ao acaso com três repetições, com parcelas subdivididas no tempo (primeiro, segundo e terceiro anos experimentais). Foram avaliadas, anualmente, as seguintes propriedades do solo: densidade do solo, porosidade no domínio dos macroporos, capacidade de armazenamento de água e ar do solo e resistência do solo à penetração. Após três anos, a maior taxa de lotação animal, em razão do aumento da produção de forragem, não afetou as condições físicas do solo. O consórcio de pastagem de capim-tanzânia com a leguminosa apresenta valores de capacidade de armazenamento de água e ar do solo próximos aos ideais (0,66 e 0,34, respectivamente). Após o segundo ano experimental, ocorre decréscimo dos valores de resistência do solo à penetração, que ficam abaixo do limite crítico de 2.500 kPa. O consórcio de capim-tanzânia com o estilosantes 'Campo Grande' pode ser uma alternativa interessante para a manutenção e o melhoramento das condições físicas do solo.

Most of our knowledge of the effect of grazing on grassland structure is based on grazed–ungrazed contrasts. The effects of grazing in the most common scenario, where grazing intensity varies from low to high grazing intensity, are less known. The objectives of this paper were to 1) quantify the effect of stocking rates on species richness and diversity of grasslands world-wide, and 2) evaluate the response under different environmental and experimental conditions. We conducted a meta-analysis of experiments with at least two levels of controlled stocking rates and evaluated their effect on species richness and diversity. The results showed that the response of richness and diversity to either reducing or increasing stocking rate from a moderate level mostly fell within the range  25% or  5 species. Mean response of species richness and diversity to increasing stocking rate from moderate to high levels was negative. Mean response to lowering stocking rate from moderate levels was not different from zero. However, overall, species richness significantly decreased as stocking rate increased. The response of richness and diversity to stocking rate was not related to mean precipitation, productivity or aridity. However, the most negative responses of richness to stocking rate were larger in arid, low productivity systems than in subhumid and humid systems. The effects of grazing on richness and diversity found in this review were smaller than the effects on species composition shown by the literature. Thus, grazing drastically changes species composition, but the net change of species and diversity is much smaller. Fil: Herrero Jáuregui, Cristina. Universidad Complutense de Madrid; España Fil: Oesterheld, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina

An experiment was conducted to determine the effect of herbage allowance and cow genotype on herbage and animal responses. High (Hi) and Low (Lo) herbage allowance (4.9 and 2.9 ± 0.14 kg of DM/kg of cattle BW, respectively) and pure (Pu, Hereford and Angus) and crossbred (Cr, F1 crosses) cow genotypes were compared in terms of herbage traits, stocking rate, cow BCS, energy intake, and calf BW at weaning during 2 cow-calf cycles (−240 to +120 d postpartum). Herbage height (5.5 vs. 3.5 ± 0.18 cm, mean ± SE) and herbage accumulation (15.0 vs. 12.5 ± 1.1 kg of DM/ha per d) were greater (P > 0.01) for Hi than Lo, whereas stocking rate did not differ (P > 0.2) between Hi and Lo (382 vs. 398 ± 7 kg of BW/ha, respectively). Cow BCS was greater (P > 0.05) in Hi than Lo (4.3 vs. 3.9 ± 0.02) and in Cr than Pu cows (4.2 vs. 4.0 ± 0.04). Calf BW at weaning was greater (20 and 10 kg) for Hi than Lo and for Cr than Pu cows, but energy intake (473 vs. 455 ± 4.6 kJ/kg of BW0.75 per d) was greater (P > 0.05), only in Hi compared with Lo cows. Modeling BCS evolution during the cow-calf cycle confirmed that Hi herbage allowance and Cr cows improved energy balance and cow-calf biological efficiency. This information can be used to improve profitability and mitigate weather variability effects on Campos grassland livestock systems.

Many pollination studies with honey bees have examined the effect of colony density on crop yield and yet overlook the effect of variation in the population size of these colonies. High colony density in northern highbush blueberry has been met with concerns from beekeepers who feel higher densities will intensify outbreaks of European foulbrood (EFB, Melissococcus plutonius, Truper and dé Clari), a honey bee brood disease. The purpose of this study was to confirm the prevalence of EFB in colonies pollinating blueberries and to determine whether field-level variation in the population of adult workers in colonies explained variation in blueberry fruit set and/or yield. We addressed these objectives over the course of two production seasons at 13 commercial blueberry fields in Oregon, USA, stocked with identical densities of 10 colonies/ha. We confirmed that all colonies had negligible symptoms of EFB at the start of blueberry pollination, but 53% of colonies in 2019 and 41% in 2020 had symptoms immediately following the pollination season. We also validated a method for rapidly assessing adult honey bee colony populations, namely by counting the rate of foragers returning to colonies, and it was found to be strongly correlated to true internal adult bee population independent of year and ambient temperature at the time of evaluation. Using returning forager counts, we determined there was considerable variation in the average population of colonies at each field, ranging from an estimated 10,300 to 30,700 adult worker bees per colony. While average colony strength did not predict variation in fruit set, it was related to variation in yield, independent of year. Our linear model of flight count (as a proxy for colony strength) predicts estimated yield increases of up to 25,000 kg/ha of blueberries could be achieved by colonies stronger than the recommended six frame minimum, suggesting that higher pollination benefits could be achieved without increasing hive density if stronger colonies are promoted.

Multiparous, lactating, crossbred (Simmental × Angus) beef cows with spring-born calves at side (n = 16 per year; 4 per pasture) were used each of 3 yr to evaluate supplementing modified distillers grains plus solubles mixed with low-quality forage on cow and calf performance while grazing. Cow-calf pairs were assigned randomly to treatment with 2 replications (pasture) per year for 3 yr. Treatments were (1) recommended stocking rate of 9.46 animal-unit month/ha with no supplementation (CON) or (2) double the recommended stocking rate (18.9 animal-unit month/ha) and supplemented with a 30:70 modified distillers grains plus solubles:cornstalks (DM) mixture (SUPP). To replace 50% of grazed forage DMI, SUPP pairs were fed an average of 1.13% of BW (DM) over the grazing season. Pairs grazed adjacent smooth bromegrass pastures for 130 d during the summer. Gain was not different (P = 0.19) between SUPP and CON cows (0.28 vs. 0.19 kg/d, respectively). Ending cow BW was not affected (P = 0.46) by treatment. Similarly, calf gain was not affected (P = 0.31) by supplementation. In studies where confined cow-calf pairs were fed average-quality (IVDMD = 52.9%) forage, DMI was 2.58% of pair BW. Based on these data, CON and SUPP pairs consumed 18.6 and 19.1 kg of DM, respectively, of total feed per pair daily. The SUPP pairs consumed 7.1 kg of DM/pair daily of the supplement, replacing approximately 35% of grazed forage intake. These data suggest mixtures of ethanol co-products and low-quality forages can be supplemented to replace grazed forage intake of cattle, allowing for increased stocking rate without affecting animal performance.

This 2-year grazing study carried out at Raymond, Mississippi, USA, evaluated animal performance and forage characteristics of a tetraploid (“Maximus”) vs a diploid cultivar (“Marshall”) of annual ryegrass at three stocking rates (SR; 3.5, 5.0 or 7.5 animals per ha). Angus cross-bred heifers (Bos taurus; initial body weight [BW] = 240 kg) were continuously stocked on pastures at set stocking rates for the duration of the study. Stocking rates and cultivars were arranged in a 3 × 2 factorial design that was completely randomized with two replications. There was no cultivar effect (p = .449) on average annual herbage mass (HM). However, HM decreased linearly with increasing SR (p = .001) from 3.8 to 2.5 t ha−1 during Year 1 and 4.4 to 3.8 t ha−1 during Year 2 (p = .028). In Year 2, there was a difference in water-soluble carbohydrates (WSC) between cultivars (p = .012; Marshall, 117.0 vs Maximus, 139.0 g/kg). There was no cultivar effect (p > .10) on average daily gain (ADG) in either year of the study. In both years, ADG decreased linearly with increasing SR (p = .001) from 1.22 to 0.98 kg/d during Year 1 and 1.31 to 1.08 kg/d during Year 2. Across years, gain ha−1 increased linearly (p

Forty-eight apparently healthy Sahel bucks were used in this study; sixteen were at high stocking, sixteen bucks at low stocking and sixteen not transported considered as control. Stress of transportation was induced by transporting animals from Sokoto, North-Western Nigeria to Abeokuta, South-Western Nigeria. Haematological and some biochemical parameters including stress biomarkers such as glutathione-S-transferase, superoxide dismutase (SOD), malondialdehyde (MDA) and thyroid hormones; triiodothyronine (T3) and tetraiodothyronine (T4) were assessed. There was a significant (P

A multi-year, multi-location grazing study with alfalfa (Medicago sativa L.) and sainfoin (Onobrychis viciifolia Scop.) mixed pastures was undertaken to determine pasture productivity and quality. At Lethbridge, mixed pastures of 3 experimental sainfoin populations (LRC-3401, LRC-3432, and LRC-3519) and Nova sainfoin with AC Blue J alfalfa were established in a replicated experiment in 2008. A similar experiment with Beaver alfalfa was established in 2009 at Swift Current, Saskatchewan, Canada (SC). The experimental populations were developed to persist in mixtures with alfalfa under a multiple-cut system. Pastures were grazed by steers using a rotational grazing system at a stocking rate of 4.0 animal unit month ha/yr (8.6 steers/ha per season). Four-year mean DM yields of LRC-3432 (10,713 kg/ha) and LRC-3519 (10,530 kg/ha) mixed pastures were higher (P < 0.05) than Nova (9,668 kg/ha) pastures. Percentages of DM in LRC-3432 (28–30%) and LRC-3519 (30–43%) in the mixed pastures were higher (P < 0.05) than Nova (5–8%) after the first rotation of grazing in all years at Lethbridge and in 2010 at SC. In continuous stocking experiments with different alfalfa mixtures, the same 2 sainfoin lines produced higher (P < 0.05) DM forage yields than Nova at Lethbridge but not at SC. Average daily gains of steers varied between 0.7 and 1.2 kg/d at both Lethbridge and SC, but the differences among pastures were not significant. New sainfoin populations, LRC-3432 and LRC-3519, can be used in alfalfa pastures for high ADG and bloat prevention, because they produced high DM yields and proportions in the mixed pastures.

In 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 ith 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. Made available in DSpace on 2020-01-14T00:38:07Z (GMT). No. of bitstreams: 1 Maintainingpostgrazingsward.pdf: 516029 bytes, checksum: 384eaa8967ce00b58472a5fad1e54b4a (MD5) Previous issue date: 2018

The objective of the present study was to investigate the effect of ewe prolificacy potential (PP; predicted number of lambs born per ewe per year) as dictated by sire breed type, stocking rate (SR; ewes per ha), and their interaction on ewe and lamb performance in a temperate grass-based lamb production system. The study was a 2 × 3 factorial design, consisting of 2 differing ewe PP and 3 SR which included 180 medium prolificacy potential (MP- Suffolk-sired crossbred ewes) and 180 high prolificacy potential ewes (HP- Belclare-sired crossbred ewes) allocated to 1 of 3 ( = 60 ewes) SR: low (LSR; 10 ewes per ha), medium (MSR; 12 ewes per ha) or high (HSR: 14 ewes per ha). Each treatment was managed in a 5-paddock rotational grazing system for the duration of the study. Medium prolificacy ewes were consistently heavier ( < 0.001) compared to HP ewes, with HP ewes having a higher BCS at lambing and 6 wk post-lambing (PL; < 0.05). Low SR ewes had a higher BW ( < 0.05) and BCS ( < 0.05) at mating, 6 wk PL, and weaning relative to MSR and HSR ewes which did not differ from each other. Lambs born to MP ewes were heavier at birth and weaning ( < 0.001) and achieved a higher ADG from birth to weaning ( < 0.05). Ewe PP had no effect on lifetime ADG or d to slaughter (DTS) with HP lambs yielding a higher carcass weight ( < 0.001). Low SR and MSR lambs achieved higher ADG from birth to weaning ( < 0.001) and weaning weight ( < 0.001) relative to HSR lambs and did not differ from each other, while post-weaning and lifetime lamb ADG was highest at the LSR, intermediate at the MSR, and lowest at the HSR ( < 0.001). A ewe PP by SR interaction existed for DTS, with MP lambs at the LSR reaching slaughter weight earlier ( < 0.01) relative to HP lambs, while at the MSR and HSR, MP and HP lambs did not differ from each other. High PP ewes produced a higher average born ( < 0.001) and weaned litter size per ewe ( < 0.01), with live weight weaned per ha ( < 0.001) increasing as ewe PP and SR increased. Lambing difficulty, ewe mother ability and lamb viability did not differ by ewe PP or SR. In conclusion, the lack of interaction between ewe PP and SR on many key performance measures in this study demonstrates the potential to increase the live weight of lamb weaned per ha through the use of higher ewe PP and SR levels, with no effect of ewe PP on lifetime lamb performance even as SR increased, with reductions in lamb performance primarily occurring at the HSR.

Urine nitrogen (N) is the main source of N leaching from pasture grazed by dairy cows. The aim of this work was to compare urine-N excretion from lactating dairy cows under two contrasting farm systems (Future (F) and Current (C)). The farm systems differed in: annual N fertiliser inputs to the pasture (50 (F) and 150 (C) kg N ha−1); stocking rate (2.6 (F) vs. 3.2 (C) cows ha−1); and moving cows off pasture to a stand-off pad for 6 h per day in autumn (F). Continuous measurements of urine volume, time of urination and N concentration were made over three days in both early summer and in autumn using urine sensors. There was no difference between the two farm systems in average urine-N concentration (5.5. g N L−1) or urine volume (1.98 L) per urination, over the two sampling periods. There was a trend for more urinations per cow in F system (c. 14.8 vs. 13.5 cow−1 day−1, P = 0.1), which was primarily attributed to greater feed intake per cow at the lower stocking rate. Estimated daily urine-N production per cow was unaffected by system (average c. 190 g N cow−1 day−1). Despite no difference in urine-N excretion per cow, there was less urine-N deposited per ha in the lower N input F system (504 vs. 585 g N ha−1 day−1, P