Forage-based Production Systems Research Articles

5 Farm-level management practices in forage-based beef cattle systems and their influence on sustainability

Abstract Sustainability is a ‘buzzword’ often used within and outside of the agriculture industry. Southeastern beef cow-calf and stocker operations often utilize management practices which embody the core definition of sustainability to improve land resource, economic, and social viability. In forage-based production systems, year-round management practices are generally viewed by the scientific community in terms of production and economic responses. However, the continual global shift in emphasis on sustainable practices creates an opportunity to view these practices through a different lens. Goals of grazing-based beef systems often include optimizing the number of grazing days per year, reducing hay and supplemental feeding period duration, and strategic supplementation during grazed forage availability gaps. Methods for increasing the grazing season length per year may include stockpiling, inclusion of multi-species mixtures, increasing species diversity on farm, and optimizing stocking strategies. Outside of associative effects of feed supplementation are potential ancillary benefits of supplementation on the plant-animal-soil interface. As an example, feed-through fertilization influences forage growth production responses and stocking density modulation in grazed beef cattle systems. The role of mineral supplementation and ionophore inclusion in beef cattle diets is well documented from an animal performance perspective, but to a lesser extent on how using these practices may influence forage or soil response variables. Stacking management practices may elicit positive animal performance responses, while potentially reducing outside inputs into the system. The question then becomes if this is economically viable compared with a more traditional forage-based system. From a research perspective, systems-level studies are more prevalent than in the past, but funding models require scientists to evolve and lead with the sustainability message rather than from a production viewpoint. Valuing management practices from an ecosystem services view is a potential area of opportunity for researchers, industry and farmers to highlight strengths of forage-based beef cattle production systems from a consumer perspective.

Effect of prolific breed type and silage type on ewe performance during late pregnancy

Multiple-bearing ewes undergo significant increases in energy and protein requirements during late pregnancy and high-quality forages are essential to meet these requirements in forage-based production systems. Three prolific breed types (Belclare X, Lleyn X, and Mule (Blue-faced Leicester ram and a Black-faced mountain ewe)) were offered one of two silage types: Italian ryegrass and red clover silage (IRGRCS) or perennial ryegrass silage (PRGS) in a 3 × 2 factorial experiment. No breed type effects were observed for ewe body weight (BW), body condition score (BCS), and combined litter weight (CLW; P > 0.05) but Mule ewes had lower dry matter (DM) and metabolisable energy intakes compared to Belclare X ewes which subsequently lead to lower colostrum yield over the first 18 h postpartum compared to Belclare X ewes with less colostrum available for their progeny per kg of birth weight (P < 0.05). Silage type had no effect on ewe DM intake, BW, BCS, colostrum yield and composition, CLW, and subsequent lamb performance (P > 0.05). When IRGRCS was offered to ewes, higher apparent efficiency of energy utilisation was achieved (P < 0.0001) with higher ruminal pH and ammonium concentrations. Overall, the nutrient composition of both silage types was similar and silage type had minimal effect on ewe and lamb performance. Prolific breed type can affect forage and nutrient intake and colostrum yield.

Importance of Foot and Leg Structure for Beef Cattle in Forage-Based Production Systems.

Understanding the relationship of foot angle and claw set to beef cattle structural soundness will be critical to the selection of animals that fit forage-based production systems. In an effort to address concerns about foot and leg structure, the American Angus Association's foot angle and foot claw set expected progeny differences (EPD) were developed in 2019. As a result, these relatively new EPD and associated guidelines have limited phenotypic data submitted thus far. While ample research has evaluated lameness and foot issues in the dairy breeds, less is known about the factors that affect foot structure in beef cattle. This review focuses on beef cattle foot and leg structure, selection factors that may have led to increased problems with feet and legs, and the importance of foot and leg structure in forage-based grazing production systems. Specifically, the importance of locomotion and freedom of movement in extensive rangeland environments is discussed relative to the current literature. In addition, environmental factors that may influence foot and leg structure are addressed as well as heritability of various aspects of foot and leg traits. Where possible, information gaps and research needs are identified to enhance further investigation and the improvement of foot and leg selection tools.

319 Predicting Urinary Nitrogen Excretion from Milk Urea Nitrogen of Fresh Forage or Total Mixed Ration Fed Dairy Cows: A Meta-analysis

Abstract Urine nitrogen excretion (g/d; UN) represent a significant environmental impact for both confinement feeding and pastoral based dairy systems. It is difficult to measure UN directly due to animal handling and labor requirements, especially in forage based production systems. The currently available milk urea nitrogen (MUN) equations have been shown to overestimate UN excretion of grazing dairy cows compared with an equation using urinary creatinine and UN concentration, indicating that diet may alter the relationship between MUN and UN. This potential was explored using data retrieved (treatment means: n = 69 and 27 for fresh forage [FF] and total mixed ration [TMR] fed cattle, respectively) from the literature and new data obtained from dairy cows fed FF (n = 15) in metabolism crates was used to test the new equations. The TMR data from literature was further split into a training set (to develop the model; n = 53) and a test set (to validate the model; n = 16). There was an interaction for diet type (P &amp;lt; 0.01) where UN (g/d) = 0.023 × MUN (mg/dL) × live-weight (kg, LW) for TMR fed cattle, (similar to a pre-established equation); however, UN (g/d) = 0.015 × MUN × LW for FF fed cattle. For FF based equations, the New MUN equation and the creatinine equation showed good precision and accuracy (Lin’s CCC = 0.79 and 0.74, respectively) and adequate predictive ability (RMSEP = 29.8 and 35.9, respectively). The new MUN equation for TMR fed cattle showed excellent accuracy and precision (Lin’s CCC = 0.87) with good predictive ability (RMSEP = 24.3) for UN excretion (observed mean = 216.5 g/d). The new equations generated during this meta-analysis provide promising predictive ability of UN excretion, which can be used for management considerations, future research, and policy making.

PSXII-29 Evaluation of Barbados Blackbelly and St. Croix sheep under accelerated lambing using purebred and terminal sire mating: Lamb survival and body weight

Abstract Objectives were to evaluate lamb survival and body weight (BW) under an accelerated, pasture-lambing system. Lambs were born to Barbados Blackbelly (BB) or St. Croix dams (SC) mated within breed (purebred) or to Dorset (terminal) in single sire mating groups. Lambs were born in April (2013 and 2015), December (2013 and 2015), and August (2014 and 2016) and weaned at 9 weeks of age. Traits considered were BW at birth (BW0; n = 959), 65-d adjusted weaning BW (BW65; n = 788), and survival to weaning (n = 959). Data were analyzed with fixed effects of dam age, sex, birth type, dam breed (BB vs SC), dam mating system (purebred vs terminal), birth month-year, and significant two-way interactions and a random dam effect. Dam breed did not impact BW65 (P = 0.09). While BW0 was greater for lambs born to SC than BB dams (3.44 vs 3.23 kg; P &amp;lt; 0.01), survival to weaning was greater for lambs born to BB than SC dams (0.93 vs. 0.87; P = 0.02). The dam mating system x birth month-year interaction was significant for both BW traits (P ≤ 0.01). Within birth month-year, BW0 was 18 to 24% greater and BW65 was 12 to 24% greater for terminal than purebred lambs (P &amp;lt; 0.01). However, BW0 differences between dam mating systems were greatest for August born lambs whereas BW65 differences were greatest for April born lambs. Lamb survival was not affected by dam mating system or birth month-year (P ≥ 0.27). Using a terminal sire improved BW without affecting survival of lambs reared by landrace hair sheep dams, making this a viable management tool to increase productivity of forage-based production systems.

142 Reproductive performance of land race hair sheep ewes in different breeding seasons under a semi-continuous production

Abstract A system for semi-continuous lamb production was evaluated using Barbados Blackbelly and St. Croix hair sheep ewes under 8-mo accelerated mating. Ewes were managed in a forage-based production system using rotational grazing. Two flocks of ewes (n = 30–35), equally representing the breeds, were bred 4 mo apart. Ewes were synchronized by feeding melengestrol acetate for 10 d, and mated in two single sire groups to like breed sires in November (NOV), March (MAR), and July (JUL) in a 25-d mating period. Pregnancy was recorded by transrectal ultrasound 22 d after breeding. Ewes were supplemented with corn/soybean meal during late gestation (0.75% of BW) and during lactation (1.5% of BW). They lambed on pasture with limited supervision, and lambs were weaned at 2 mo of age. Lambs had access to the supplement provided to ewes. Ewe performance (pregnancy rate, litter size, lamb survival, and birth and weaning weight) was recorded during a 2 yr production cycle, and analyzed for the effect of mating season. Pregnancy rate was not statistically different (P &amp;gt; 0.1) between season, and ranged from 93.9% in NOV, to 85.9 and 86.6% in MAR and JUL. Litter size (lambs born/ewe lambing) was higher (P &amp;lt; 0.05) in NOV (2.09) than MAR (1.68) and JUL (1.82). Lamb survival at birth was reduced (P &amp;lt; 0.001) in JUL (86.5%) compared to NOV (99%) and MAR (100 %), but was not different between seasons for survival to weaning (86 to 90%). Lamb birth weights were higher (P &amp;lt; 0.05) in MAR (3.16 kg) than JUL (2.99 kg), with NOV (3.05 kg) intermediate, while lamb weaning weights were higher (P &amp;lt; 0.001) in NOV (13.6 kg) compared with MAR (11.9 kg) and JUL (11.4 kg) mating. Data suggest that dual flock, accelerated mating of landrace hair sheep ewes can produce lamb cohorts of similar size in 4 mo intervals under a low-input, forage-based production system.

Seasonal nitrous oxide and methane fluxes from grain- and forage-based production systems in wisconsin, USA.

Agriculture in the midwestern United States is a major anthropogenic source of nitrous oxide (NO) and is both a source and sink for methane (CH), but the degree to which cropping systems differ in emissions of these gases is not well understood. Our objectives were to determine if fluxes of NO and CH varied among cropping systems and among crop phases within a cropping system. We compare NO and CH fluxes over the 2010 and 2011 growing seasons from the six cropping systems at the Wisconsin Integrated Cropping Systems Trial (WICST), a 20-yr-old cropping systems experiment. The study is composed of three grain and three forage cropping systems spanning a spectrum of crop diversity and perenniality that model a wide range of realistic cropping systems that differ in management, crop rotation, and fertilizer regimes. Among the grain systems, cumulative growing season NO emissions were greater for continuous corn ( L.) (3.7 kg NO-N ha) than corn-soybean [ (L.) Merr.] (2.0 kg NO-N ha) or organic corn-soybean-wheat ( L.) (1.7 kg NO-N ha). Among the forage systems, cumulative growing-season NO emissions were greater for organic corn-alfalfa ( L.)-alfalfa (2.9 kg NO-N ha) and conventional corn-alfalfa-alfalfa-alfalfa (2.5 kg NO-N ha), and lower for rotational pasture (1.9 kg NO-N ha). Application of mineral or organic N fertilizer was associated with elevated NO emissions. Yield-scaled emissions (kg NO-N Mg) did not differ by cropping system. Methane fluxes were highly variable and no effect of cropping system was observed. These results suggest that extended and diversified cropping systems could reduce area-scaled NO emissions from agriculture, but none of the systems studied significantly reduced yield-scaled NO emissions.

Grazing behaviour, physical activity and metabolic profile of two Holstein strains in an organic grazing system

The challenge for sustainable organic dairy farming is identification of cows that are well adapted to forage-based production systems. Therefore, the aim of this study was to compare the grazing behaviour, physical activity and metabolic profile of two different Holstein strains kept in an organic grazing system without concentrate supplementation. Twelve Swiss (HCH ; 566 kg body weight (BW) and 12 New Zealand Holstein-Friesian (HNZ ; 530 kg BW) cows in mid-lactation were kept in a rotational grazing system. After an adaptation period, the milk yield, nutrient intake, physical activity and grazing behaviour were recorded for each cow for 7 days. On three consecutive days, blood was sampled at 07:00, 12:00 and 17:00 h from each cow by jugular vein puncture. Data were analysed using linear mixed models. No differences were found in milk yield, but milk fat (3.69 vs. 4.05%, P = 0.05) and milk protein percentage (2.92 vs. 3.20%, P < 0.01) were lower in HCH than in HNZ cows. Herbage intake did not differ between strains, but organic matter digestibility was greater (P = 0.01) in HCH compared to HNZ cows. The HCH cows spent less (P = 0.04) time ruminating (439 vs. 469 min/day) and had a lower (P = 0.02) number of ruminating boli when compared to the HNZ cows. The time spent eating and physical activity did not differ between strains. Concentrations of IGF-1 and T3 were lower (P ≤ 0.05) in HCH than HNZ cows. In conclusion, HCH cows were not able to increase dry matter intake in order to express their full genetic potential for milk production when kept in an organic grazing system without concentrate supplementation. On the other hand, HNZ cows seem to compensate for the reduced nutrient availability better than HCH cows but could not use that advantage for increased production efficiency.

Integration of forage, beef, and hog production systems in Western Canada: An economic assessment

This study was conducted to evaluate the economic sustainability of single enterprise farming operations when compared to integrated operations. The single operations consisted of either a hog only production system, a forage-based production system or beef cattle on pasture and the integrated operations were either a hog–forage or hog–beef production system. The hypothesized benefit of integration was the relatively inexpensive supply of nutrients from the hog facilities which may be applied to forage land used in both hay and beef cattle production, resulting in improved forage yield and cattle stocking rates. Net income from a 500-sow farrow-to-finish operation was analysed along with net income from a 349-ha forage production system and a 349-ha cattle production system. The 349-ha land area was an estimate of the forage area needed to spread the manure from the hog operation at nutrient removal rates governed by provincial (Manitoba, Canada) legislation. At ten year average prices, the single-enterprise beef and forage operations were not profitable, losing $2838/year and $34,169/year, respectively. Integration of single-enterprise operations with the hog operation made integrated operations viable, with additional profits of $50,935/year (beef) and $9894/year (forage), over and above the profit of the hog portion of the operation, as a consequence of the additional nutrients provided in the form of manure. Annual net income of the integrated hog–forage operation was 2% greater than the hog only operation that treats manure as a waste. Further, the integrated hog–beef operation realized a 10% increase in net income as a consequence of integration.

Strategies for rapid rebreeding of lactating ewes in the spring

Rapid rebreeding of winter- and spring-lambing ewes is essential if ewes are to lamb more than once per year, but fertility of lactating ewes is often low and early weaning of lambs may be undesirable in forage-based production systems. Selection to improve fertility in spring matings has been successful and led to development of ewes with a reduced seasonal anestrus. Potential for rapid rebreeding of lactating out-of-season breeding (OOS) ewes was tested in three studies. In Experiment 1, effects of short-term lamb removal on rebreeding was evaluated over 2 years using 71 January-lambing OOS ewes. At an average of 63 days postpartum, 36 ewes had lambs removed for 72 h, and all ewes were joined with rams. Circulating progesterone levels indicated that 74% of ewes ovulated before lamb separation; 91% of ewes mated within 5 weeks of ram exposure, 85% were diagnosed as pregnant and 75% lambed. The average interval between lambings was 225 days. In contrast to results observed in cattle, none of the measured variables was affected by lamb separation (P>0.20). Experiment 2 compared rebreeding performance of 24 OOS and 23 St. Croix ewes that lambed in January and averaged 60 days postpartum at ram introduction. More OOS ewes ovulated, mated and became pregnant during the first 21 days of ram exposure (83.3%, 58.3%, and 41.7%, respectively; P<0.001) compared with St. Croix ewes (26.1%, 0%, and 0%, respectively). After 39 days of ram exposure, pregnancy rates still favored OOS ewes (66.7% v. 39.1%; P=0.06), but the percentage of ewes that lambed did not differ (P>0.20) between OOS (47.8%) and St. Croix ewes (34.8%). In the third study, 34 March-lambing OOS ewes were exposed to rams on May 3 at an average of 40 days postpartum to characterize their reproductive performance. After 39 days of ram exposure, 52.9±8.7% of the ewes had mated, and 38.2±8.5% were diagnosed as pregnant. However, only 20.6±7.0% of the ewes produced viable lambs, suggesting a high level of uterine insufficiency. Spring fertility of lactating OOS ewes in these studies was one of the highest reported in the literature and indicated that selection for fertility in spring mating would improve reproductive performance in accelerated lambing programs. However, exposure of lactating OOS ewes to rams at 30 to 50 days postpartum was associated with high prenatal lamb mortality.

Effect of forage type in the stocker phase and its effect on subsequent feedlot performance and carcass characteristics of beef steers

ABSTRACT The focus of most research on beef weaning programs is to evaluate effects of age and diet on calf performance with a particular interest on preconditioned health program to maximize BW gain. In support of the forage-based production system, research needs to be conducted to evaluate the potential of different forages to facilitate weaning and continuation into forage-based development programs. In each of 2 yr, 48 weaned beef steers were used to evaluate performance when grazing monocultures of endophyte-free tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire = Festuca arundinacea Schreb.; TF] and alfalfa (Medicago sativa L.; ALF) and the effect of these stocker treatments on subsequent performance and carcass characteristics. Forages were not limiting in terms of mass produced and nutritive value. The greater nutritive value of ALF resulted in greater performance and pounds of beef produced per hectare compared with steers grazing TF. Steers grazing ALF tended to be heavier at the beginning of the feedlot phase, and the difference resulted in heavier (P

Nitrogen management in grasslands and forage-based production systems – Role of biological nitrification inhibition (BNI)

Nitrogen (N), the most critical and essential nutrient for plant growth, largely determines the productivity in both extensive and intensive grassland systems. Nitrification and denitrification processes in the soil are the primary drivers of generating reactive N (NO3 - , N2O and NO), largely responsible for N loss and degradation of grasslands. Suppressing nitrification can thus facilitate retention of soil N to sustain long-term productivity of grasslands and forage-based production systems. Certain plants can suppress soil nitrification by releasing inhibitors from roots, a phenomenon termed ‘biological nitrification inhibition’ (BNI). Recent methodological developments [e.g. bioluminescence assay to detect biological nitrification inhibitors (BNIs) from plant-root systems] led to significant advances in our ability to quantify and characterize BNI function in pasture grasses. Among grass pastures, BNI capacity is strongest in low-N environment grasses such as Brachiaria humidicola and weakest in high-N environment grasses such as Italian ryegrass (Lolium perenne) and B. brizantha. The chemical identity of some of the BNIs produced in plant tissues and released from roots has now been established and their mode of inhibitory action determined on nitrifying Nitrosomonas bacteria. Synthesis and release of BNIs is a highly regulated and localized process, triggered by the presence of NH4 + in the rhizosphere, which facilitates release of BNIs close to soil-nitrifier sites. Substantial genotypic variation is found for BNI capacity in B. humidicola, which opens the way for its genetic manipulation. Field studies suggest that Brachiaria grasses suppress nitrification and N2O emissions from soil. The potential for exploiting BNI function (from a genetic improvement and a system perspective) to develop production systems, that are low-nitrifying, low N2O-emitting, economically efficient and ecologically sustainable, is discussed.

Factors influencing the long-term competitiveness of commercial milk producers: evidence from panel data in East Griqualand, South Africa

This study investigates factors influencing the long-term competitiveness of 11 commercial milk producers from East Griqualand (EG), South Africa using unbalanced panel data for the period 1990 to 2006. Results of a ridge regression analysis show that dairy herd size, the level of farm debt, annual production per cow, technology and policy changes over time, and the ratio of trading income to total milk income influence the long-term competitiveness of these milk producers. To enhance their competitiveness in a deregulated dairy market, relatively small and profitable EG milk producers should consider increasing their herd sizes, as the importance of herd size in explaining competitiveness suggests that size economies exist. All EG milk producers should consider utilising more pasture- and forage-based production systems to lower feed costs and select dairy cattle of superior genetic merit to improve milk yields on pasture.

Microbial Populations on Hides of Grazing Steers in a Forage-Based Production System in Uruguay

The objective of the study was to evaluate the microbiological status of hides of grazing steers in a typical forage-based system in Uruguay. The study was conducted on a single farm with samples taken on 3 days during the spring of 2007. Four anatomical hide sites (perineum area, flank, back, and shoulder) of 10 steers were individually swabbed each sampling day at the farm environment (n = 120). Each sample was analyzed by the Laboratorio Tecnológico del Uruguay for aerobic plate counts (APC), total coliform counts (TCC), and Escherichia coli counts (ECC). Mean log values for APC, TCC, and ECC on external animal hide surfaces, across all sampling sites, were 5.52, 1.89, and 1.70 log CFU/cm2, respectively. There were no significant differences among bacterial counts from the four hide surface locations. Mean log values for APC, TCC, and ECC were 1.49, 1.15, and 1.12 log CFU/cm2 lower, respectively, on sampling day 2 than on sampling day 3. Microbial populations on hides of grazing steers are highly variable and dependent on climatic and environmental conditions. To our knowledge this is the first study published evaluating the hygienic conditions of grazing livestock operations in Uruguay and their potential implications on the red meat chain.

Comparison of Conventional and Minimal Tillage for Low-Input Pasture Improvement

In forage-based production systems farmers are frequently confronted with a decision of when, or whether, to reseed pasture in order to maintain or improve productivity. At its simplest such a decision would be guided by evaluation of the costs of improvement in relation to the benefits accruing from the newly-sown pasture but, in practice, costs may be difficult to define. In addition to labor, equipment, and material costs of the field operations necessary for planting, there are less obvious costs that result from production losses during the period of ground preparation and establishment of a new crop. While it is generally assumed that these production losses may be compensated over time by increased productivity in a reseeded pasture, the period of amortization may be prolonged (75,80). Hopkins et al. (51) found that yield benefits deriving from reseeded compared with continuous pasture were largely eliminated when establishment-year production shortfall of the reseed was considered. Lack of persistence, slow establishment of reseeds, and periodic stand failure will further compromise the long-term productivity of reseeded pastures and the economic viability of a reseeding program (6,9,77). Much has been published on the effectiveness of seeding by minimal-tillage methods, but the focus of work has been on as an alternative to conventional cultivation and sowing for establishment of annual crops (67). Less attention has been given to its impact on pastures or on its value in low-input pasture systems, where resource constraints make reduced cultivation and infrequent reseeding especially desirable. Seeding pasture by offers several potential advantages over conventional methods, including cost savings resulting from reduced cultivation, reduced risk of soil erosion, improved trafficability of land, and reduced damage by grazing animals (67). However, the potential of to reduce establishment-phase production loss by minimizing damage to existing pasture has not been specifically addressed. Nor is it clear whether the savings in cultivation and planting effort that use of permits are offset by longer-term impacts of reduced pasture productivity, reduced persistence and a need for more frequent pasture renewal. This literature review assesses the value of minimum for pasture improvement and its particular application in lowinput systems. Presentation of data. For comparison of performance parameters (emergence or yield), minimal tillage has been interpreted to mean seeding by no-till or conventional drill into ground undisturbed except for the passage of the seeder, or by broadcasting onto untilled or frost-tilled ground [pre-plant 0 to 3 on the 0 to 10 scale used by Wolf et al., (95)]. Data sources were selected to provide direct comparison between and conventional seeding practices, and parameter values have been expressed as a percentage of no-till drill values (= 100) unless otherwise noted, to allow comparison among disparate experiments and crop types. Four main categories of minimal-tillage seeding were identified: cool-season grass sown into cool-season grass (CSGCSG); cool-season grass sown into warm-season grass (CSG-WSG); cool-season legume sown into cool-season grass (CSL-CSG); and cool-season legume sown into warm-season grass (CSL-WSG). Some instances of cool-season grass sown

Partitioning the contributions of forage-based production system components to weight gain of juvenile crayfish ( Procambarus clarkii)

Because commercial aquaculture of the crayfish, Procambarus clarkii, depends mainly on a foragebased production system, management could benefit from a better understanding of the linkages between system food components and growth of crayfish. This study was designed to estimate the contribution of this production system's separable dietary components to juvenile crayfish growth and assess the system's limitations. Crayfish weight gain was determined in static-water microcosms with and without various dietary components of the forage-based production system and a prepared feed. Crayfish were held individually in 3.8-1 glass jars with water maintained at 26.5 ± 1.5 °C and supplied with supplemental aeration. Approximately 450 ml of pond soil (except where absence of soil was used as a treatment) and unfiltered pond water (except when different water sources were used as treatments) provided the basic simulated production system. Six-week weight gain data from three separate feeding trials were used to fit a multiple linear model with zero intercept to estimate contribution to growth from separable components of the system. These components were — in decreasing order of importance — prepared feed, microbially enriched detrital forage, soil benthos, soil substrate and possibly peron associated with detritus. Nitrogen and phosphorus amendments to microcosms under the conditions of this study failed to improve crayfish weight gain. Likewise, microbial biomass of detrital rice (as estimated by ATP concentration) was not affected by either addition.