Daily Grazing Research Articles

Configuration of daily grazing and searching of growing beef cattle in grassland: observational study

Many of the studies in Campos grasslands focus on management aspects such as the control of herbage allowance, and application of nutrients and/or overseeding with legumes. However, there is little literature on how the Campos grassland resource is utilised, especially regarding the grazing pattern and the relationship between pasture quantity and quality on daily grazing activities. The study of the ingestive behaviour in species-rich and heterogeneous native grasslands during daylight hours, and understanding how animals prioritise quality or quantity of intake in relation to pasture attributes, are important to comprehend the ingestive-digestive processes modulating the energy intake of animals and to achieve a better grazing management. Therefore, the objective was to describe and quantify the daily grazing behaviour of growing cattle grazing native pasture with different structures as a result of different management practices, and study the relationship of pasture attributes and intake through multivariate analysis. The study was carried out at the Faculty of Agronomy, Paysandú, Uruguay. Treatments were native grassland, overseeding with Trifolium pratense and Lotus tenuis + phosphorus, and native pasture + nitrogen-phosphorus. Grazing activities were discriminated into grazing, searching (defined when animals take 1–2 bites in one feeding station and then change to another feeding station and so on), ruminating and idling. The probability of time allocated to each activity was continuously measured during daylight hours (0700–1930) and was related to pasture structure and forage quality using regression tree models, while the bite rate was determined every 2 h. The diurnal pattern of growing cattle showed grazing and searching sessions, followed by ruminating and idling sessions. The length of sessions (as the probability of time allocated to each activity) varied throughout the day. The grazing probability was greater during afternoon than morning and midday (0.74 vs 0.45 vs 0.46, respectively), and it was associated with higher bite rate (34.2 bites/min). Regression tree models showed different grazing, searching and ruminating strategies according to pasture attributes. During the morning, animals modified grazing, searching, ruminating and idling strategies according to bite rate, crude protein in diet and herbage allowance. At midday, they only adjusted ruminating and idling, while during afternoon sessions, grazing activities were modified by pasture quantity attributes such as herbage mass and herbage allowance. By controlling the herbage allowance, herbage mass and pasture height, animals prioritise quality in the morning and quantity in the afternoon, integrating and modifying the grazing-searching and ruminating-idling pattern.

Tropical grass and legume pastures may alter lamb meat physical and chemical characteristics.

The present study assessed the influence of the type of the tropical pastures on lamb body weight (BW) gain and meat quality. Fifty-four lambs were allocated to three grazing pastures: (1) AG - Aruana grass (Panicum maximum cv. IZ-5); (2) PP - pigeon pea legume (Cajanus cajan cv. Anão); and (3) CS - contiguous swards, half of the paddock with AG and half with PP. After 92days of grazing, the lambs were slaughtered. Carcasses were evaluated and the longissimus muscle was collected to determine color, lipid profile, tocopherol concentrations, and lipid oxidation. Although the pastures present differences in the characteristics of nutritional quality, the animals did not show difference in BW gain. The results show that all forage presented similar concentration of alpha-tocopherol (137 ± 14.37mgkg-1 of fresh matter), whereas total and condensed tannin contents were greater in PP, intermediate in CS, and the lowest in AG treatment (P = 0.0001). Meat α-tocopherol content was similar among treatments (P = 0.1392), with an average concentration close to the optimal level to reduce the meat oxidation. Meat from AG treatment had 45 and 25% lower n-6/n-3 ratio than meat from PP and CS treatments, respectively. The legume increases the unsaturated fatty acids and the grass can reduce the n6/n3 ratio. The level of condensed tannin concentration did show to have important effect on meat characteristics. Both tropical pastures studied can provide a high amount of alpha-tocopherol, generating a great potential to increase the concentration of this antioxidant in lamb's meat.

Estimation of diet organic matter digestibility in grazing dairy cows

ABSTRACT Precise and continual information on the energy supply from pasture is mandatory for managing grazing ruminants. Therefore, estimating the organic matter (OM) digestibility from faecal crude protein concentration using the regression equation, OM digestibility [%] = 79.76–107.7 · e(−0.01515 · faecal crude protein [g/kg OM]), is known to be a suitable tool. However, essential information regarding faeces sampling times and the required number of samples are not yet available. We therefore analysed the OM digestibility data of an experiment with dairy cows grazing two pasture types and receiving two concentrate types over 6 d in three independent runs. Both pasture type and grazing day affected the OM digestibility estimates, whereas concentrate type and intake did not, indicating that this method reliably detects small changes in OM digestibility of pasture without being interfered by moderate concentrate supplementation, selective grazing behaviour or differences in feed intake. Likewise, as sampling time did not influence OM digestibility, faeces sampling once daily can be recommended to be sufficient for an accurate estimation of OM digestibility. The variance within pasture type and grazing day amounted for 1.1 percentage units of estimated OM digestibility, which enabled to define the minimum sample number required to detect given differences in OM digestibility with adequate statistical certainty. In conclusion, estimating OM digestibility from faecal crude protein concentration is an applicable and sensitive method to reliably detect differences in the quality of ingested pasture using a limited number of animals. Therefore, instructions for faeces sample collection were provided.

Ingestive behavior of Girolando heifers in integrated crop, livestock (ICL), and forestry (ICLF) systems

ABSTRACT Aiming to compare integrated crop, livestock (ICL) and forest (ICLF) systems in relation to ingestive behavior of dairy heifers, a 2 × 2 crossover trial was conducted with two periods and two systems. Eight Girolando (3/4holstein × 1/4 Gyr) heifers were evaluated in pasture of Xaraés palisade grass (Urochloa brizantha ‘Xaraes’ syn Brachiaria brizantha) managed with intermittent stocking. The ICLF systemhad eucalyptus trees planted in tiers with 65% crown cover. Ingestive behavior parameters were obtained using acoustic data collected with mP3 recorders for 48hours. Statistical analysis was performed using the mixed procedure of SAS, and means were compared using the Tukey-Kramer test at 5% significance. The dry mater intake (DMI), number of daily grazing sessions, and the duration of the grazing sessions did not differ (P<0.05) between systems. A higher (P<0.05) bite rate and total daily bites and lower (P<0.05) bite mass was observed in the ICLF system in relation to ICL. Heifers in shaded pasture change their ingestive behavior in comparison with those in full-sun pasture.

Can FT-Mid-Infrared Spectroscopy of Milk Samples Discriminate Different Dietary Regimens of Sheep Grazing With Restricted Access Time?

Milk obtained from sheep grazing natural pastures and some forage crops may be worth a plus value as compared to milk obtained from stall-fed sheep, due to their apparently higher content of beneficial fatty acids (FAs). Fourier transformed mid-infrared (FT-MIR) analysis of FA can help distinguish milk from different areas and diverse feeding systems. The objective was to discriminate milk from sheep and milk from dairy sheep rotationally grazing Italian ryegrass or berseem clover for 2, 4, or 6 h/day. To test this hypothesis, a data-mining study was undertaken using a database of 1,230 individual milk spectra. Data were elaborated by principal component analysis (PCA) and analyzed by linear discriminant analysis (LDA) with or without the use of genetic algorithm (GA) as a variable selection tool with the primary aim to discriminate grazed forages (grass vs. legume), access time (2, 4, or 6 h/day), grazing day (first vs. last grazing day during the 7-day grazing period), and the milking time (morning vs. afternoon milking). The best-fitting discriminant models of FT-MIR spectra were able to correctly predict 100% of the samples differing for the pasture forage, 91.9% of the samples differing for grazing day, and 97.1% of the samples regarding their milking time. The access time (AT) to pasture was correctly predicted by the model in 60.3% of the samples, and the classification ability was improved to 77.0% when considering only the 2 and 6 h/day classes.

Evaluation of cool-season binary mixtures as pasture: Herbage yield, nutritive value, and beef cattle performance

• Hybrid bromegrass-legume mixtures produced 54% more biomass than Russian wildrye-legume mixtures at Lanigan site, while biomass did not differ between mixtures at Swift Current site. • Legume contribution to total biomass was greater at Swift Current than at Lanigan site, and alfalfa contributed more to biomass than sainfoing at Lanigan site. • Crude protein tended to be greater for RWR mixtures than HBG mixtures at Lanigan site. • Beef steer gain was similar for all binary mixtures at Swift Current site, however steer gain was greater at Lanigan site for sainfoin mixtures, suggesting inclusion of legume in pasture was beneficial. • Results demonstrate that all four binary mixtures appear to be suitable for late summer and fall grazing. ABSTRACT A 3-year study (2016, 2017, and 2018) was conducted to compare the effects of alfalfa (ALF; cv. Yellowhead) (Medicago falcata L.) or sainfoin (SF; cv. AAC Mountainview) (Onobrychis viciifolia Scop.) in mixtures with either Russian wildrye (RWR; cv. Tom) (Psathyrostachys junceus [Fisch.]) or hybrid bromegrass (HBG; cv. Success) (Bromus riparius Rehm × B . inermis Leyss) on herbage dry matter yield (DMY) and nutritive value, and beef yearlings performance at two sites: Swift Current (Brown soil zone) and Lanigan (Thin Black soil zone), Saskatchewan, Canada. In 2015, in each site, sixteen 0.7-ha (in Lanigan) or 0.8-ha (in Swift Current) paddocks were established with replicated ( n = 4) ALF-HBG, ALF-RWR, SF-HBG, or SF-RWR binary mixtures. Each year in August, yearling steers (16 ± 1 month and BW = 391 ± 1.7 kg and 350 ± 0.04 kg for Swift Current and Lanigan sites, respectively) were allocated to paddocks for an average 30-d grazing trial to utilize 40–60% of available herbage. The DMY (3629 ± 154 kg/ha) did not differ ( P > 0.05) among mixtures at Swift Current. The HBG included (ALF-HBG and SF-HBG) mixtures produced 54% more ( P < 0.01) DMY than RWR included (ALF-RWR and SF-RWR) mixtures (4542 vs. 2943 kg/ha, SEM = 303) at Lanigan. Legume contribution to DMY was greater at Swift Current than at Lanigan (33.1% ± 2.1% vs. 14.0 ± 1.7%), and ALF contributed more to DMY than SF at Lanigan (18.0 vs. 10.1%). Crude protein tended ( P = 0.10) to be greater for RWR mixtures than HBG mixtures (93.5 vs. 83.4 g/kg DM for RWR and HBG mixtures, respectively) at Lanigan. The yearling steers had similar ( P = 0.25) ADG (0.78 ± 0.03 kg/d) for the treatments at Swift Current. However, at Lanigan, the animal ADG differed ( P < 0.01) with 0.88 and 0.90 kg/d for ALF-RWR and SF-RWR and 0.53 and 0.63 kg/d for ALF-HBG and SF-HBG mixtures, respectively. The HBG mixtures (ALF-HBG and SF-HBG) produced approximately 10 more grazing days (GD) (AUD/ha) than the RWR (ALF-RWR and SF-RWR) mixtures at both, Swift Current (95 vs. 88 AUD/ha, SEM = 9) and Lanigan (112 vs. 101 AUD/ha, SEM = 7) sites. Sainfoin-grass mixtures produced 8 and 3 GD less (AUD/ha) than ALF-grass mixtures at Swift Current and Lanigan, respectively. Overall, these results demonstrate that all 4 binary mixtures appear to be suitable for late summer and fall grazing to provide sufficient nutritive value and beef cattle steer performance in both soil zones of Saskatchewan, Canada.

Effect of pasture management on enteric methane emissions from goats.

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

Forage production and steer performance in fertilized smooth bromegrass and smooth bromegrass–legume pastures

AbstractSmooth bromegrass is a commonly used cool‐season pasture grass that responds favorably to annual spring fertilization, but annual fertilizer applications require annual inputs of both time and expense. This study was conducted to determine if interseeding legumes into established smooth bromegrass pasture is a viable alternative to spring fertilization. Steers (Bos taurus) were rotationally grazed in either fertilized smooth bromegrass pastures or smooth bromegrass pastures interseeded with legumes. Data were collected on forage production, forage available at the beginning of each grazing rotation, steer weight gain, and the number of grazing days. Total forage production for the growing season was not different between the pasture types, but fertilized pasture had greater available forage early in the growing season and interseeded pasture had greater forage production late in the growing season. Season‐long average daily gain of steers was not different between pasture types, but daily gains were greater in interseeded pasture late in the growing season and may be linked to proportionally greater abundance of legumes late in the season. Beef production ac–1 was higher in interseeded pastures, largely due to increased days of grazing. We found that interseeding legumes into established pasture can be a viable alternative to annual spring fertilization and may outperform fertilized pasture depending on the metric and growing conditions.

Do pastoralist cattle fear African lions?

Fear of predators fundamentally shapes the ecology of prey species and drives both inter‐ and intra‐specific interactions. Extensive research has examined the consequences of predation risk from large carnivores on the behavior of wild ungulate prey species. However, many large carnivores not only hunt wild prey but also depredate domestic livestock, especially in pastoralist systems where livestock share land and resources with large carnivores. Northern Tanzania is a hotspot for human–carnivore conflict driven by livestock depredation and interactions are particularly severe between African lions Panthera leo and pastoralist cattle Bos taurus. In this ecosystem, we explored the degree to which pastoralist cattle exhibited anti‐predator behaviors during their daily grazing routines. Using focal animal sampling, we compared two typical anti‐predator behaviors, vigilance and grouping, among cattle in village rangelands with high and low background depredation rates. We found that cattle in high risk village rangelands formed 21.2% larger groups than cattle in low risk village rangelands. Interestingly, cattle in low risk village rangelands spent 68.4% more time vigilant than cattle in high risk village rangelands. These patterns were influenced significantly by the time of day: as sunset approached, cattle in low risk village rangelands spent more time vigilant and cattle in high risk village rangelands formed larger groups. These results suggest that pastoralist cattle exhibit anti‐predator strategies that vary both spatially and temporally, and that such strategies might help livestock optimally tradeoff the costs and benefits of anti‐predator behavior across timescales (i.e. the risk allocation hypothesis). We discuss the implications of our results for husbandry techniques that might reduce behavioral costs associated with cattle anti‐predator behaviors and help increase tolerance for lions and other large carnivores. These improvements are critical to human–carnivore coexistence given the prevalence of pastoralism globally and the rising potential for conflict with large carnivores such as lions.

Lamb growth rates and carcass characteristics of White Dorper and crossbred lambs grazing traditional and novel pastures during spring in southern Australia

Context Finishing lambs on pasture and specialist forages is a commonly used production system in southern Australia; however, there is little information properly comparing multiple pasture options for lamb production. Aim We aimed to compare growth rates of lambs when grazing traditional pastures, novel legumes, or a herb–legume mixture. Methods Six pasture and forage treatments were sown in three replicate 0.4-ha plots and with access to irrigation. Treatments were French serradella (Ornithopus sativus Brot.), bladder clover (Trifolium spumosum L.), forage brassica (Brassica napus L.), lucerne (Medicago sativa L.), lucerne + phalaris (Phalaris aquatica L.), and arrowleaf clover (Trifolium vesiculosum Savi) + chicory (Cichorium intybus L.). The last two treatments were sown in a 1 : 1 alternate sowing-row (tyne) arrangement. All plots were grazed concurrently from 15 October to 2 December 2014, each plot with a mixed-sex group of 13 weaned lambs: five White Dorper, three White Suffolk × White Dorper and five White Suffolk × Merino lambs. During the grazing period, lambs were weighed each week following an overnight curfew. Starting liveweight (mean ± s.d.) was 32.4 ± 5.5 kg. At the completion of the grazing period, lambs were slaughtered and carcass traits recorded. Key results Lambs grazing arrowleaf clover + chicory had the highest average daily growth rates (ADG) (245 g/lamb.day) and those grazing lucerne + phalaris the lowest (119 g/lamb.day). There was a lag in ADG for the forage brassica treatment over the first 14 days of grazing, and lamb growth plateaued for the bladder clover treatment toward the end of the trial. Overall, ADG for the forage brassica and bladder clover treatments was similar to that for lucerne. Lambs grazing French serradella had similar ADG to 18 November compared with those grazing other treatments, except arrowleaf clover + chicory; however, lambs grazing French serradella were withdrawn from the experiment on 26 November after losing weight. The genotype × treatment interaction was significant for final liveweights, with White Suffolk × White Dorper lambs having higher predicted final liveweight on the arrowleaf clover + chicory pasture (45.2 kg) than White Dorper (43.8 kg) and White Suffolk × Merino (44.0 kg) lambs, and higher liveweight on lucerne than White Suffolk × Merino lambs (42.6 vs 41.4 kg). White Dorper lambs had a higher overall sale value owing to their higher dressing percentage. The proportion of lambs reaching the finished weight target was higher for arrowleaf clover + chicory (0.96) than for any other treatment. Conclusions and implications Using a forage option that maintains high levels of production and quality later in spring can increase the proportion of lambs reaching target weights and the final sale weight of lambs.

Threshold values to discriminate grazing activity of dairy cows by an uni-axial accelerometer as affected by grazing season and herbage mass

Recording grazing time is important because the time allocated for each grazing event is one of the limitations to achieving high intake levels. Grazing time can be measured via visual observation or, more recently, by devices calibrated for this purpose. The Kenz Lifecorder Plus (Suzuken Co. Ltda., Nagoya, Japan) has been used to record daily grazing time with high accuracy, but none of the previous studies have analyzed how pasture characteristics and grazing management influence the recording sensitivity of this device. Thus, the aim of this study was to evaluate the effect of pre-grazing herbage mass and season of the year on the activity level recorded by the Lifecorder Plus and its resulting threshold value used to determine a grazing event for dairy cows. A randomized 2 × 2 factorial design was used to evaluate the effect of two pre-grazing herbage masses (HM), medium herbage mass (MHM) and high herbage mass (HHM), in two seasons, winter (WIN) and spring (SPR), on the observed and predicted grazing time. In each period, two groups of six Holstein Friesian cows were fitted with a Lifecorder Plus in a collar attached to their neck. The pasture characteristics and observed and predicted grazing times were measured. There was no effect (P > 0.05) of HM on the observed grazing time. The grazing time in SPR was significantly higher (P < 0.001) than that in WIN. There was no effect (P> 0.05) of HM on the threshold value. The threshold value for SPR was significantly higher (P < 0.001) than that for WIN. The mean relative prediction error of all treatments was 0.07, which implies a precision of 0.93 in grazing detection and demonstrates a high level of precision in the estimation of daily grazing time. Determining an independent threshold value for each treatment was necessary to obtain a high degree of precision in estimating grazing time. In conclusion, changes in the structural sward characteristics caused by grazing management or the annual cycle of growth of the pasture affect both the activity level recorded using a Lifecorder Plus and the threshold value obtained to detect grazing events in dairy cows. When studies incorporate factors that might alter grazing behavior, a specific threshold value for the study conditions needs to be determined to estimate the grazing time of dairy cows with higher precision.

276 Repeated Measures of PAP at Different Elevations in Beef Bulls in Colorado

Abstract High Mountain Disease (HMD) in cattle is a consequence of altitude-induced (&amp;gt; 1500 m) pulmonary hypertension (PH). Pulmonary arterial pressure (PAP; mmHg) is an indicator of PH-HMD and moderately heritable. This study analyzed repeated measures of PAP in growing bulls and estimated correlations across elevations and ages. Data included breed, PAP, elevation, weights and ages in spring-born bulls from the Agriculture Research, Development, and Education Center (ARDEC) in Colorado. Five PAP measurements were collected from each bull: 1) Weaning PAP at ARDEC (1,525 m); 2) Yearling PAP at ARDEC (i.e., gain-test); 3) PAP after acclimating for 28 days at Fort Lewis College (FLC; 2,470 m); 4) before returning to ARDEC from FLC after 110 days of grazing; and 5) after re-acclimating for 57 days to the moderate elevation and feeding systems at ARDEC when bulls were 18 months of age. Across these 5 times in Angus (n = 18) and Hereford (n = 12) bulls, PAP measures were: 1) 37.97 ± 0.37; 2) 40.93 ± 0.77; 3) 46.10 ± 1.48; 4) 45.00 ± 1.11; and 5) 42.23 ± 0.67, respectively. Breed and elevation-age were important (P &amp;lt; 0.05) sources of variation. Also, PAP changed (P &amp;lt; 0.05) across the 5 time periods (i.e., increased with altitude and then declined as bulls returned to moderate altitude). Yearling PAP measurements collected at 1,525 m were highly correlated with PAP measures at 2,470 m, as well as a PAP collected at 18.3 ± 0.1 mo of age at 1,525 m (r = 0.93 to 0.99); therefore, suggesting that the yearling PAP measurement collected at 1,525 m in gain-tested bulls was an adequate predictor of PAP at elevations of 1,525 and 2,470 m as bulls aged to 18 months; however, additional study of bovine PAP across elevations, ages, and rates of gain is warranted.

PSV-11 Grazing diverse combination of tanniferous and non-tanniferous legumes: Implications for foraging behavior, performance and hair cortisol in beef cattle

Abstract We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle foraging behavior, performance and hair cortisol concentration. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of seven treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design in two 25-d periods during 2 consecutive years. The fewest grazing events occurred in BFT (42.0% of the total scans recorded; P &amp;lt; 0.10), with other treatments ranging between 47.8 (SF-BFT) and 52.6% (ALF-SF) of the total scans recorded. Heifers selected a varied diet, preferring SF over BFT or ALF in 46:27:27 and 70:30 ratios (3- and 2-way choice, respectively) and preferred BFT over ALF (62:38 ratio). All treatments followed similar daily grazing patterns (P &amp;gt;0.10), with two major grazing events (1 hour after sunrise and 3 hours before sunset). No differences among treatments were observed for the number of steps taken, motion index, or percentage of time spent standing (1,600, 5,356, and 45.3%, respectively; P &amp;gt;0.10), suggesting that heifers in choice treatments did not invest extra time in walking, searching or patch-switching activities relative to monoculture treatments. Heifers in the 3-way choice gained more BW (1.27 Kg/d) than in monocultures (1.00 kg/d; P = 0.014), or 2-way choices (0.97 kg/d; P = 0.007), suggesting nutritional synergism among legumes in the treatment of greatest diversity. No differences in hair cortisol concentration were observed among treatments, with values ranging between 1.40 (BFT) and 2.12 ng/g (3-way choice) (P &amp;gt;0.10). Thus, forage diversity enhanced animal performance, likely driven by interactions among condensed tannins and dietary protein, without affecting hair cortisol levels or grazing efficiency, explained by the spatial arrangement (strips) of the forage species presented.

95 Impact of daily movement with low or higher target residue on ewe weight gain and parasite infestation

Abstract Impact of grazing method on ewe performance, parasite infestation, and soil, was examined using mature, non-lactating Katahdin ewes. Pasture consisting of primarily common bermudagrass/crabgrass mixture previously grazed by sheep was divided into four, approximately one acre paddocks [two with a target of 3 cm residue (SR; short residue) and two with a target of 13 cm residue (LR; long residue)] and soil sampled. On May 17 (d 0), 5 ewes were placed on each paddock and provided with daily grazing allocation using temporary electric fence. Body weight and fecal egg count (FEC) was recorded biweekly beginning on d 0. On alternate weeks, ewe body condition score (BCS) and FAMACHA score was recorded. After 84 days of grazing, final data and soil samples were collected. BCS, FAMACHA, FEC, body weight, and soil test results were tested for effect of treatment (SR vs LR), day, and treatment by day interaction using procedures for repeated measures with JMP software (version 10, SAS Inst. Inc., Cary, NC). There was an effect of treatment (P = 0.0345) and day (P &amp;lt; 0.0001) on BCS such that BCS was greater for LR than SR, and d 63 and 77 was greater than 35 and 49. There was an effect of day on body weight (P = 0.0008) such that body weights were greater on d 70 and 84 than d 0, 14, and 28. There was a tendency for a treatment by day interaction (P = 0.0766) on FEC such that FEC was greater for SR on d 70 and 84 than all other treatment days except SR on d 56 and LR on d 0. No effects on FAMACHA score or soil parameters were significant. These data indicate daily rotation with a higher target residue can result in improved body condition and lower FEC.

96 Impact of daily movement with low or higher target residue on ewe weight gain and parasite infestation

Abstract Impact of grazing method on ewe performance, parasite infestation, and soil, was examined using mature, non-lactating Katahdin ewes. Pasture consisting of primarily common bermudagrass/crabgrass mixture previously grazed by sheep was divided into four, approximately one acre paddocks (two with a target of 3 cm residue [SR; short residue) and two with a target of 13 cm residue (LR; long residue)] and soil sampled. On May 17 (d 0), 5 ewes were placed on each paddock and provided with daily grazing allocation using temporary electric fence. Body weight and fecal egg count (FEC) was recorded biweekly beginning on d 0. On alternate weeks, ewe body condition score (BCS) and FAMACHA score was recorded. After 84 days of grazing, final data and soil samples were collected. BCS, FAMACHA, FEC, body weight, and soil test results were tested for effect of treatment (SR vs LR), day, and treatment by day interaction using procedures for repeated measures with JMP software (version 10, SAS Inst. Inc., Cary, NC). There was an effect of treatment (P = 0.0345) and day (P &amp;lt; 0.0001) on BCS such that BCS was greater for LR than SR, and d 63 and 77 was greater than 35 and 49. There was an effect of day on body weight (P = 0.0008) such that body weights were greater on d 70 and 84 than d 0, 14, and 28. There was a tendency for a treatment by day interaction (P = 0.0766) on FEC such that FEC was greater for SR on d 70 and 84 than all other treatment days except SR on d 56 and LR on d 0. No effects on FAMACHA score or soil parameters were significant. These data indicate daily rotation with a higher target residue can result in improved body condition and lower FEC.

Liveweight and carcass characteristics of White Dorper and Crossbred lambs grazing lucerne, subterranean clover, biserrula or a choice of subterranean clover plus biserrula in southern Australia

Context Biserrula (Biserrula pelecinus L.) is a relatively new legume species in Australia that has been shown to maintain higher quality forage late in the season than subterranean clover (Trifolium subterraneum L.). Aim This study investigated the suitability of lucerne (Medicago sativa L.), subterranean clover and biserrula, or a choice of both biserrula and subterranean clover, for finishing White Dorper and White Suffolk × Merino lambs during spring. Methods An experiment was established near Wagga Wagga, NSW, in 2013 in a randomised complete block design with three replicates and four pasture treatments grazed by lambs during late spring and early summer. Liveweight, carcass weight and GR fat depth of White Dorper and White Suffolk × Merino lambs grazing lucerne, subterranean clover, biserrula or a choice of subterranean clover plus biserrula were compared. Key results Lambs grazing lucerne had significantly (P &lt; 0.05) higher final liveweight, carcass weight and GR fat depth than lambs grazing other pasture treatments. After 61 days of grazing, mean liveweight of lambs grazing lucerne, subterranean clover and subterranean clover plus biserrula was higher than of lambs grazing biserrula monoculture. In vitro digestible organic matter digestibility and crude protein content indicated that lambs grazing biserrula should have achieved growth rates at least as high as lambs grazing subterranean clover. Sheep genotype and pasture type affected final liveweight. Final liveweight was higher for White Dorper lambs when grazing the subterranean clover plus biserrula treatment than the subterranean clover monoculture (45.6 vs 44.5 kg; P &lt; 0.05) but was similar for White Suffolk × Merino lambs grazing these treatments (47.3 vs 47.2 kg; P &gt; 0.05). Conclusions Provision of a companion species or mixture of species when lambs graze biserrula during late spring to summer appears to offer benefits for lamb growth rate over this period.

The value of stubbles and chaff from grain crops as a source of summer feed for sheep

Context Modern crop stubbles provide an important source of feed for sheep during summer but can vary widely in their feeding value due to Genetics × Environment × Management interactions during crop growth, and how chaff is managed at harvest. Stubbles are difficult to assess for grazing value, due to the heterogeneity of forage components (e.g. stem, leaf, grains), which means that livestock producers rely on their observations and experience to manage sheep grazing stubbles. Aims To provide current information on the feeding value of stubbles, and to establish better methods for estimating stubble feeding value. Methods In the present paper, we report the results of sheep grazing wheat-stubble paddocks and a survey of the nutritive value of standing stubbles and chaff lines and piles of grain crops (including wheat, barley, canola and lupins) from crop paddocks in the mixed-farming region of Western Australia. Key results Without supplementation, wheat stubbles provided 50–100 dry sheep equivalent grazing days per hectare, before the estimated metabolisable energy (ME) intake of sheep fell below maintenance. This was influenced by ewe body condition score, where sheep of lower body condition gained more weight on stubbles (89 g/day higher weight gain per unit lower body condition score). Estimated ME content of edible chaff (leaf, fine stem and seed sheath or pod, excluding main stem and grain) was 5% higher in barley, 19% higher in lupin, and 5% lower in canola, than in wheat chaff, which was 5.9 MJ ME/kg DM. Implications While the grazing value of modern stubbles is variable, they have an important role in the seasonal feedbase by providing several months of feed during summer. Chaff by itself does not meet the energy or protein requirements of livestock, so a high-protein grain supplement (e.g. lupins) is necessary to maintain non-lactating ewes fed only chaff. The increased use of chaff lines and piles at harvest, primarily for weed control, provides a new opportunity to fill feed gaps in sheep and cattle enterprises if the material can be transported and stored efficiently, or if grazed in situ, as is common practice.

Nitrate leaching risk is increased under exercise grazing in organic farming

ABSTRACT There is a trend in organic dairy farming towards higher milk yields associated with more concentrates and less grazing. Grazing is usually compulsory but grass intake from grazing varies greatly. This has consequences for nitrogen (N) transfer from stable to field and for the risk of N leaching. Our aim was to compare different management options for grazing in moderate to intensive organic farming. In a 2-year study, five differently managed fields on three farms in northwest Germany were compared. We analysed parameters of milk production and grassland management, calculated N balances and quantified residual soil mineral N (SMN) as an indicator for N leaching. Residual SMN (0–90 cm) varied on average from 33 to 84 kg N ha−1 in grazed areas and from 71 to 180 kg N ha−1 in functional areas like watering places. Soil mineral N increased with higher stocking rate, more grazing days and higher N surpluses. Consequently, SMN was higher in pastures used for exercise grazing or night grazing and around watering places. We conclude that intensifying organic dairy farming when associated with a massive N transfer from stable to field, little fodder uptake on pasture, and higher stocking rates increases N leaching risk.

How lamb production systems can affect the characteristics and sward structure of Tifton 85 pasture?

Abstract Aimed at understanding how lamb production systems can affect sward structure in tropical grass pastures, the productive, structural and morphological characteristics of Tifton 85 (Cynodon spp.) pasture were evaluated in four systems: non-weaned and non-supplemented lambs (NW); non-weaned lambs receiving concentrate supplementation in creep feeding (CF); early-weaned lambs not supplemented (W); and early-weaned lambs supplemented with concentrate (WS). The trial lasted 105 days and was set out in a randomized block design with four treatments (systems), three replications (paddocks) and five lambs per replication. In the systems with weaning, lambs were weaned at 46 ± 6 days of age and immediately allocated to the paddocks; in the systems with supplementation, lambs received daily a protein–energy concentrate at 2% body weight (BW) on a dry matter (DM) basis. Continuous stocking management was used and the forage allowance was kept at 12% BW in DM/day in all systems. Changes in the structural and morphological characteristics of pasture were more intense up to 63 days of grazing. Sward height and forage mass were higher in WS compared to NW and CF systems, and forage accumulation rate was also higher in WS compared to the other systems. The mass of leaves and stems were higher in the WS system than in NW. Higher heterogeneity of pasture morphological characteristics was observed when weaning was performed. Forage mass was concentrated up to 20 cm sward height in the systems without weaning, with stem mass concentrated in the 0–10 cm stratum and leaf mass highly exposed to grazing in the 10–20 cm stratum. The systems with weaning presented the greatest dispersion of leaves and stems in all sward strata, which increased when the concentrate supplementation was provided to the lambs. Independent of concentrate supplementation to the lambs, the systems without weaning resulted in a better sward structure, with higher leaf/stem ratio for the animals on Tifton 85 pasture. In addition, supplementation of weaned lambs had a deleterious effect on sward structure.

Human Ecology of Daily Grazing and Pasture Land Use by a Nomad’s Community in Western Mongolia

Human Ecology of Daily Grazing and Pasture Land Use by a Nomad’s Community in Western Mongolia