Grazing Conditions Research Articles

Assessing the individual and combined use of Caesalpinia coriaria (Plantae: Fabaceae) and Duddingtonia flagrans (Fungi: Orbiliaceae) as sustainable alternatives of control of sheep parasitic nematodes

ABSTRACT The consumption of Caesalpinia coriaria dry ground fruit (Ccgf) and a Duddingtonia flagrans chlamydospore suspension (DfchS) either individually or in combination for the control of gastrointestinal nematodes (GIN) was assessed in sheep. Forty-five lambs infected with GIN were distributed into five groups (n = 9): Group 1: DfChS at 5 × 105 chlamydospores /kg BW; Group 2: Ccgf at 10% of the total diet; Group 3: Combination of both treatments; Group 4: Levamisole at 6 mg/kg BW; and Group 5: Control. The DfChS was orally administered every third day for 15 days; while the Ccgf, was daily offered during the same period. Faecal egg counts and coprocultures were established. Mean faecal egg accounts (EPG) and infective larvae from coprocultures were recorded. The highest EPG reductions were obtained on the 17th day with the treated group (72.1%); followed by Ccgf group (69.1%) at day 13 and DfchS group (62.6%) also on the 17th day; though, no significant differences were found among treatments. The highest larval reductions were observed with the combined treatment 97.7% (day 17); followed by DfchS group: 96.2% (day 11) and Ccgf group: 70% (day 11). The EPG and larvae reductions achieved with DfchS and Ccgf could be associated to the anthelmintic compounds present in both fungi and plants. The combined use of DfchS and Ccgf against GIN in sheep under grazing conditions seems to be a promising alternative for GIN control in sheep.

ВЛИЯНИЕ ЗАПОВЕДНОСТИ И ВЫПАСА НА СТРУКТУРУ ЦЕНОПОПУЛЯЦИЙ В СООБЩЕСТВЕ FESTUCA VALESIACA GAUDIN

Population analysis of plant communities makes it possible to predict the development and transformation of natural cenoses under anthropogenic effect, to solve problems aimed at optimizing the biogeocenotic cover. The Festuca valesiaca Gaudin community was studied in the southern arid zone of Russia. The experiment was carried out in the Baskunchak-Kharabalin plain in the specially protected area of the Bogdinsko-Baskunchaksky Nature Reserve, where the grazing regime is moderate. In the first case, cenopopulations of the normal type predominate, which is an indicator of their stability and the stability of the community as a whole. Grazing intensifies the processes of vegetative reproduction and seed invasion from other cenoses. This increases the number of individuals and species diversity. Under grazing conditions, the number of non-stable – invasive and invasively regressive cenopopulations increases. The Bassia prostrata (L.) Beck (Chenopodiaceae), Astragalus dolichophyllus Pall. (Fabaceae), Agropyron desertorum (Fisch ex Link) Schult. (Poaceae), Agropyron fragile (Roth) P. Candargy (Poaceae) cenopopulations fall first out of the community composition. The dominant Festuca valesiaca centropopulation plays a significant phytocoenotic role in steppe and semi-desert biocenoses and shows a high degree of stability without changing its parameters in the grazed area. It is concluded that moderate grazing, while increasing the species diversity of the community and the number of individuals, causes destabilisation and regression of a number of non-dominant cenopopopulations.

Falling between the Cracks of the Governing Systems: Risk and Uncertainty in Pastoralism in Northern Norway

Abstract Rapid and interacting change poses an increasing threat to livelihoods and food production, and pastoralists in Nordland, northern Norway, are at a crossroads both economically and culturally. Some of these changes are localized and pertain to changing weather and grazing conditions caused by climate change and land fragmentation. Others, driven by national management policies and governance specifically related to predators, are poorly adjusted for the different and localized contexts. The pastoralists are inherently adaptive and have a long history of responding well to variable changing conditions. This is now changing with the continued increasing pressures from many directions. The central government systematically ignores pastoralists’ traditional knowledge and enforces narrow sector policies to be implemented at regional and local levels. We address the effect of how institutional, physical, and societal constraints challenge pastoralists’ prospects for sustainable adaptation. Our results show how pastoralists’ livelihoods become compromised and potentially threatened because they are forced to respond in ways that they know are counterproductive in the long run. Adaptation outcomes are affected by different approaches and epistemologies that are situated across scale and context in terms of regional and national regulations versus local empirical reality among the pastoral communities. This study concludes that radical change is needed toward a more holistic governance in which multiple knowledge systems are integrated to ensure sustainable adaptation at all levels. This study is based on extensive and long-term fieldwork among reindeer herders and sheep farmers in Nordland, through a collaborative process of knowledge coproduction.

载畜率对荒漠草原冷蒿植物种群密度及其空间分布的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 载畜率对荒漠草原冷蒿植物种群密度及其空间分布的影响 DOI: 10.5846/stxb202102060390 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31760143）；内蒙古重大科技专项（ZDZX2018020）；内蒙古自治区科技成果转化项目（2020CG0013）；科技成果转化项目（2019CG069） Effects of stocking rate on population density and spatial distribution of Artemisia frigida in desert steppe Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:载畜率是衡量草原生产能力的指标之一，研究荒漠草原冷蒿（Artemisia frigida）植物种群在不同载畜率下的耐牧程度和空间分布特征，对退化草原的恢复具有重要的指导意义。以短花针茅荒漠草原优势种冷蒿为研究对象，在4个不同载畜率放牧试验设计（对照区CK （0只/hm2）、轻度放牧区LG （0.93只/hm2）、中度放牧区MG （1.82只/hm2）和重度放牧区HG （2.71只/hm2））小区中选择代表性样地（面积为40m×40m），采用机械取样法进行取样，记录冷蒿植物种群的密度，使用SAS 9.4软件对其进行描述性统计和方差分析，并用地统计学软件GS+9.0进行空间异质性统计分析。结果表明：荒漠草原优势种冷蒿密度、出现频率和单位均值上的变异值随载畜率增大都明显下降，其植物种群空间分布的决定性因素随载畜率增大由结构性因素转变为随机性因素。LG和HG处理区的空间自相关距离较大，但这两者表现结果的影响因素存在差异。在CK和HG区，冷蒿空间分布斑块化较为明显，LG区的冷蒿空间分布的特征表现为带状分布，MG区冷蒿空间分布形成了一处大的条带和零星的几块斑块。基于上述研究结果可以得出，随着载畜率增加，荒漠草原冷蒿种群密度下降，空间分布趋于单一化，导致冷蒿的生产力下降，进而影响草地的可持续利用。 Abstract:Stocking rate is one of the most important indicators to measure the productivity of grassland. Study on the grazing tolerance and spatial distribution characteristics of Artemisia frigida population under different stocking rates in desert steppe has significant effects for the restoration of the degraded grassland. The experiment design selected Artemisia frigida, a dominant species in Stipa breviflora desert steppe as the research object, which conducted with four different stocking rates (CK, 0 sheep unit hm-2; LG, 0.93 sheep unit hm-2; MG, 1.82 sheep unit hm-2; and HG, 2.71 sheep unit hm-2), and the representative sample plot (40 m×40 m) with the same terrain in each treatment was selected. The plant population density of Artemisia frigida is recorded by mechanical sampling method. Then, the descriptive statistics and variance analysis were performed by SAS9.4 software, and the spatial heterogeneity was analyzed using statistical software GS+9.0. The results showed that the density, frequency of occurrence, and the variation of mean value of Artemisia frigida decreased significantly with the increase of stocking rate. The spatial distribution decisive factor of plant population changed from structural factor to random factor with the increase of stocking rate. The fractal dimension value D0 was ranked from large to small under different stocking rates is CK>HG>MG>LG, under different grazing conditions, the values of fractal dimension were between 1.700 and 2.000, indicating that the spatial distribution of these four regions with different stocking rates was relatively uniform. The spatial auto-correlative distances in LG and HG treatments were relatively larger than other treatments, which caused by different impact factors, LG area was significantly affected by random factors, and HG area was significantly affected by structural factors. With the increase of stocking rate, the spatial correlation of Artemisia frigida gradually weakened. Artemisia frigida has different spatial states in different stocking rates, the spatial distribution of Artemisia frigida were patchy in CK and HG treatments, while it was characterized by banded distribution in LG treatment, and it formed a large strip and scattered patches in MG treatment, the density distributions of LG and MG were similar, but the uniformity of MG is greater than LG treatment. Based on the research results above mentioned, we can conclude that the population density of Artemisia frigida decreased and the spatial distribution tended to be simplified, resulted in the decrease of productivity of Artemisia frigida with the increase of stocking rate, which affected the sustainable utilization of grassland in the desert steppe. 参考文献 相似文献 引证文献

Holstein strain affects energy and feed efficiency in a grazing dairy system

Context Improving the partitioning of the energy consumed by dairy cows towards milk-solid production is a priority in grazing diary systems because energy efficiency has been associated with sustainability. Different selection criteria in the Holstein breed have led to divergent Holstein strains with different suitability to grazing systems. Aim The objective of this work was to quantify and evaluate the energy partitioning between maintenance and milk production of two divergent Holstein strains (New Zealand Holstein and North American Holstein) in a grazing system without supplementation of concentrate. Methods New Zealand Holstein and North American Holstein cows, nine of each, in mid-lactation (183 ± 37 days in milk, mean ± s.d.) were allocated in a randomised block design and evaluated under grazing conditions. The cows were managed under a daily strip-grazing system and grazed perennial ryegrass as the only source of nutrients. After an adaptation period of 14 days, heat production, retained energy in milk and metabolisable energy intake were measured over 7 days, and animal behaviour was simultaneously recorded. Key results Milk yield did not differ between Holstein strains, but fat and protein content were greater for New Zealand than North American Holstein cows; consequently, retained energy in milk was 13% greater for the former strain. Heat production did not differ between Holstein strains, but metabolisable energy intake (kJ/bodyweight0.75.day) was greater for New Zealand than North American Holstein cows, which was associated with a greater pasture dry matter intake relative to their body weight. Both feed and energy efficiency were greater for New Zealand than North American Holstein cows. Conclusions The results supported that the New Zealand Holstein strain has greater energy and feed efficiency, demonstrating that it could be more suitable to be managed under a grazing dairy system without supplementation than the North American Holstein strain. Implications The New Zealand Holstein strain may be suited to selection as a dairy cow with the capacity to fulfil energy requirements from pasture, which is a key factor to improve production efficiency of grazing dairy systems.

Calcium and magnesium supplementation of ewes grazing pasture did not improve lamb survival

Context Clinical deficiencies of calcium and magnesium may result in the metabolic disorders hypocalcaemia and hypomagnesaemia, resulting in ewe and lamb mortality. However, the contribution of subclinical deficiencies to perinatal lamb mortality in grazing flocks is unclear. Aims To test the hypothesis that calcium and magnesium supplementation during the lambing period would increase lamb survival to marking age. Methods In 2017, an on-farm study used five flocks across New South Wales, South Australia and Western Australia. On each farm, twin-bearing mature Merino ewes (n = 400–600) grazing pasture were allocated to two replicates of control and supplemented treatments. The supplemented groups were offered 30 g/ewe per day of a loose lick containing magnesium chloride (MgCl2(H2O)6), calcium sulfate (CaSO4·(H2O)2, and salt (NaCl), in the ratio 12.5:32.5:55.0, designed to have a low dietary cation–anion difference (−390 meq/100 g). A second study was conducted in 2018 on one farm to test the form of supplement. This study used two replicates of three treatments: control; a low-dietary cation–anion difference supplement as used in 2017; and a standard lime, Causmag (calcined MgO) and salt loose mix (ratio 1:1:1). Mature twin-bearing composite ewes (n = 600) were allocated to groups and those supplemented were offered minerals for the last month of pregnancy and during the lambing period. Blood and urine samples were collected in both experiments for analyses of mineral concentrations. Key results In the 2017 study, only two flocks consumed >10 g/ewe of supplement per day, and supplementation did not increase lamb survival to marking age in these flocks. In the 2018 study, the mean consumption of supplement was 18 or 20 g/ewe per day. Of non-supplemented ewes, 61% were deficient in plasma calcium (≤90 mg/L) and 17% were deficient in magnesium (≤18 mg/L) at Day 140 after the start of joining. Lamb survival was not increased by supplementation and was 77 ± 3.8% in both treatments. Conclusions Calcium and magnesium supplementation did not increase lamb survival. Implications Lamb survival was not increased by calcium and magnesium supplementation; however, evaluation under a wider range of grazing conditions with adequate supplement intake is required.

Similar grazing mechanisms explain contrasting intake and sward-height dynamics under different grazing management

Context Average sward height has traditionally been used as a grazing management variable. However, such approach ignores the spatio-temporal heterogeneity of swards. Because the intake rate responds non-linearly to average height at plant level, we expected that sheep exposed to contrasting grazing methods with similar average heights would behave differently. Aims We hypothesised that low-intensity, high-frequency grazing results in a higher daily intake rate than does high-intensity, low-frequency grazing, despite both methods having similar average sward heights over space and time. Also, we asked whether sheep exhibit the same foraging mechanisms for a given instantaneous sward state regardless of long-term grazing conditions imposed. Methods We exposed sheep to two contrasting grazing methods with similar average height; low-intensity, high-frequency (LIHF), and high-intensity, low-frequency (HILF). We then evaluated their foraging behaviour using continuous bite-monitoring paired with detailed sward measurements during grazing down. Key results Sward height decreased markedly during the grazing period in both treatments, but the sward height depletion was faster under HILF (7.5 cm and 20.3 cm for LIHF and HILF), which means that sward structure was severely disrupted. The animals exhibited markedly different herbage intake patterns between the grazing methods, with sheep under LIHF presenting greater total daily herbage intake (850 vs 630 g DM per individual). Also, sheep demonstrated a more stable and higher instantaneous intake rate in the LIHF. Despite the difference in total daily herbage intake, the grazing treatments did not affect the behavioural mechanisms beyond their indirect effects on the rate of change in the instantaneous sward conditions. Grazing treatments created different patterns of sward change and intake rate over time, but the local and instantaneous sward conditions determined intake rate regardless of the grazing method. Conclusions Intake responses of sheep differed between grazing methods with similar average height due to sward heterogeneity over time and space. Grazing mechanisms were not directly affected by the treatments but were influenced by the sward heterogeneity imposed by the grazing management. Implications Grazing management requires not only consideration of the average sward height, but also an understanding of how the resource is distributed in time and space.

克氏针茅草原群落物种多样性与生物量关系对放牧强度的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 克氏针茅草原群落物种多样性与生物量关系对放牧强度的响应 DOI: 10.5846/stxb202110162921 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41861024，42161023）；内蒙古自然科学基金（2021BS04001）；内蒙古自治区高等学校科学技术研究项目（NJZZ21006） Relationship between species diversity and biomass of Stipa krylovii steppe community and its responses to grazing intensity Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:放牧强度引起的草原植物群落物种多样性与地上生物量变化是近年来草地生态系统研究的热点问题。以内蒙古锡林郭勒克氏针茅草原为研究对象，探究植物群落结构特征、物种多样性与地上生物量之间相互关系及其对不同放牧强度的响应。结果表明：随着放牧强度的增加植物群落结构逐步向退化方向演替；植物群落高度逐渐降低（P<0.05），密度逐渐增加（P<0.05），盖度总体呈下降趋势（P<0.05）；植物群落和原有群落优势种地上生物量总体呈下降趋势（P<0.05），而退化指示物种的地上生物量逐渐增加（P<0.05）；轻度、中度放牧条件下群落物种Margalef指数、Pielou指数、Simpson指数均显著高于重度放牧（P<0.05）；地上生物量与Shannon-Wiener指数、Margalef指数和Pielou指数呈正相关关系，而与Simpson指数呈负相关关系。综上所述，克氏针茅草原植物群落结构和功能在不同放牧强度下产生不同的响应，适度放牧有利于提高群落物种多样性与生物量。 Abstract:In recent years, the species diversity and aboveground biomass changes of steppe plant communities caused by grazing intensity have been hot issues in steppe ecosystem research. This paper takes the Stipa krylovii steppe of Xilin Gol in the Inner Mongolia as the research object, explores the relationship between characteristics of plant community structure, species diversity and aboveground biomass, and clarifies response to different grazing intensities. The results showed that the plant community structure gradually succeeded in the direction of degradation with the increase of grazing intensity. The height of the plant community gradually decreased (P<0.05) while the density of that gradually increased (P<0.05), and the overall coverage showed a downward trend (P<0.05). The aboveground biomass of plant communities and the dominant species of the original community showed a general downward trend (P<0.05), while that of the degraded indicator species gradually increased (P<0.05). The Margalef index, Pielou index, and Simpson index of community species under mild and moderate grazing conditions were significantly higher than those of heavy grazing (P<0.05). Aboveground biomass was positively correlated with Shannon-Wiener index, Margalef index and Pielou index, but showed a negative correlation with the Simpson index. In summary, the structure and function of the Stipa krylovii steppe plant community produce different responses in different grazing intensities, and moderate grazing is beneficial to increase the community's species diversity and biomass. 参考文献 相似文献 引证文献

Estimation of the phytoplankton biomass in Bahia Manzanillo, Colima (2016-2017)

Phytoplankton biomass (Chl-a) was estimated in 7 stations of Manzanillo Bay, Colima on the surface and at the Secchi depth in the rainy and dry season (2016-2017). To evaluate the biomass, a Millipore equipment and fiberglass GF / F filters were used using the spectrophotometric technique (Lorenzen, 1967). The physicochemical parameters were estimated with a YSI 85 equipment and the nutrients using a San Plus II segmented flow autoanalyzer. The average depth of the Secchi disk ranged from 5.9 m at the Puerto station to 12.8m at the center (A1 and A2). The temperature ranged from 26.9 to 28.1 ° C, the salinity between 31.6 and 33 ups and the dissolved oxygen from 3.81 to 4.82 mg L-1. The nutrients presented high values in Puerto, A1 and Carrizales. The central part of the bay registered values greater than one mg of Chl-a and a maximum of 2.67 mg .m-3 in the Puerto station. In 2016, Chl-a decreased significantly because of a very intense Niño event, also showing high concentrations of phaeopigments, which reveal grazing conditions or degraded chlorophyll. Through an analysis of variance, it was determined that there is a significant difference between the chlorophyll-a values (p≤0.05).

Identification of Somatostatin Receptor Subtype 1 (SSTR1) Gene Polymorphism and Their Association with Growth Traits in Hulun Buir Sheep.

This study was conducted to evaluate SSTR1 gene polymorphisms and their association with growth traits in Hulun Buir sheep. We followed 233 Hulun Buir sheep from birth to 16 months of age, born in the same pasture and on the same year under a consistent grazing conditions. The body weight (BW), body height (BH), body length (BL), chest circumference (ChC), chest depth (ChD), chest width (ChW), hip width (HW), and cannon circumference (CaC) were measured and recorded at birth, 4 months, 9 months, and 16 months of age. The polymorphisms of the SSTR1 gene in Hulun Buir sheep were excavated using exon sequencing, and association analyses of between SNPs and growth traits at each growth stage were conducted. The results showed that there were four SNPs in Exon 2 of the SSTR1 gene, SNP1, SNP2, and SNP3 were low mutation sites, and SNP4 was a moderate mutation site. Four SNPs were consistent with Hardy–Weinberg equilibrium, and all of them were synonymous mutations. The association analyses found that the genotypes of SNP2 were significantly associated with WW and BH at 4 months of age, BW, BL, ChC, and HW at 9 months of age (p < 0.05), and extremely significantly associated with ChD at 4 and 9 months of age (p < 0.01). There were significant associations between SNP3 and BH at 9 months of age, between SNP4 and ChD, ChW, and CaC at 9 months of age, and BW and ChC at 16 months of age (p < 0.05). There were no detectable associations with growth traits among the seven haplotypes between the SNP1, 3, and 4 of a strong linkage disequilibrium (p > 0.05). These results indicated that SNP2, SNP3, and SNP4 may be used as molecular markers for growth traits of Hulun Buir sheep.

The effect of concentrate feeding strategy and dairy cow genotype on milk production, pasture intake, body condition score and metabolic status under restricted grazing conditions

The objective of this study was to compare the effects of contrasting concentrate feeding strategies and dairy cow genotypes on milk production, pasture intake, energy balance, and metabolic status under restricted grazing conditions. Fifty-eight Holstein Friesian cows were assigned to concentrate feeding strategy and genotype treatments in a 2 ˣ 2 factorial arrangement, in a randomized complete block design. Treatments were balanced for days in milk, parity, previous 305-day milk yield, and body condition score (BCS). The dietary treatments offered over the 11-week experimental period were a low flat rate concentrate allowance of 1.76 kg DM/d typical of a low input system (CON, n = 29) or a “feed to yield” concentrate allowance (FY, n = 29). The FY treatment included feeding a base of 1.76 kg DM plus 0.44 kg DM of concentrates/kg of milk above the base milk yield. All cows were allocated 13 kg DM of grass. The genotype treatments consisted of lower fertility higher milk (LFHM) and higher fertility lower milk (HFLM) cows based on Economic Breeding Index figures. The FY strategy resulted in a higher milk (+ 1.77 kg/d) and a higher fat plus protein yield (+ 0.12 kg/d) and increased BCS (+ 0.12 units) compared to CON. The metabolic status of FY cows differed from CON cows as evidenced by the reduced β-hydroxybutyrate and non-esterified fatty acid concentrations. Genotype did not influence milk output but did affect total dry matter intake (DMI) and BCS. Cows of LFHM tended to have higher yields on the FY resulting in increased milk yield of 11% compared to FY-HFLM cows. Cows of HFLM fed CON had greater fat and protein output of 0.5 kg and 0.5 kg, respectively compared to the CON-LFHM. No differences in feed efficiency was observed between treatments. Despite cows originating from a higher output herd, differences in genotype had a significant effect on the response to the concentrate feeding strategies. These observations are important when identifying suitable genotypes or feeding strategies that most suit grazing systems.

Effect of energy and protein levels in supplemental diets on performance of Rayeni cashmere does and goat kids under natural grazing conditions

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Assessment of a non-invasive accelerometer for detecting cattle urination and defecation events

Nitrogen (N) excreted in the urine from cattle is the primary source of N leaching loss from grazed pasture systems. The objective of this study was to use non-invasive accelerometer sensors to detect the time and duration of urination and defecation events from grazing cattle. Two accelerometer sensors were attached to cows to detect the back arching of cows during urination and defecation events. Trials were conducted under outdoor grazing conditions in autumn and summer with a total of 160 urination recorded events. Changes in tilt angle of 8–22.5 degrees were observed during most urination and defecation events. Ensemble machine learning models to predict urination and defecation events were developed based on 18 selected features of a cow back arching event. The accelerometer urination event classifier had an F1 statistic of 0.80 (harmonic mean of precision (0.82) and sensitivity (0.78)) and the defecation event classifier had an F1 statistic of 0.73 (based on 408 h of data obtained 9a.m. to 3p.m. from 19 cows). Models to predict urination event duration were significant but had low performance partly due to the moderate association between the duration of back arching and the duration of the urination event (R2 of 0.29 and 0.47 for the autumn and summer trials, respectively). This demonstrates the potential for non-invasive accelerometer sensors to identify the urination characteristics of individual cows and provide individual farm information that could be used as an input parameter in farm decision support tools (e.g. urine-N excretion) and farm management decisions (e.g. culling/breeding).

Heat tolerance in cows of British breeds and their crosses with bonsmara under grazing conditions.

The objective of this study was to evaluate the influence of the increasing temperature-humidity index (THI) on the body temperature of cows from different breed groups. Vaginal temperature was monitored in cows from two breed groups: a) British breeds (Hereford, Angus and their crosses, n=4); and b) their crosses with Bonsmara (BO, n=6). Vaginal temperature in cows of British breeds was always higher (P<0.05), and the higher temperature picks coincide with afternoon hours. British cows maintained stable their vaginal temperature if THI was lower than 72.8, but for higher values, they showed linear increases. Moreover, the threshold THI associated to increase in vaginal temperature in British breeds was 72.8. However, vaginal temperature remained unchanged in Bonsmara crosses. The present work suggests that THI greater than 72.8 could affect the body temperature in grazing cattle of British breeds but not its crosses with Bonsmara.

Grazing Sheep in Organic Vineyards: An On-Farm Study about Risk of Chronic Copper Poisoning

Many winegrowers and sheep breeders are interested in wintertime grazing in vineyards, as an agroecological alternative to mowing or herbicide spraying, and additional supply of forage. Still, strong concern is raised by the use of copper-based fungicides, particularly in organic vineyards, since copper is known to induce chronic toxicosis in sheep. We conducted an on-farm study with n = 12 1-year-old Merinos × Mourerous ewes grazing the cover vegetation of vineyard plots during wintertime, in order to check whether this agricultural practice might be harmful to sheep. Our results indicate that most copper found in the cover vegetation originates from fungicide spraying versus plant uptake from the soil, and that rain-induced washing-off and plant growth-triggered dilution of copper are crucial to reach close-to-safe grazing conditions. Furthermore, we found that while sheep remained globally healthy during the 2 months of the experimental period, the plasma activity of Glutamate Dehydrogenase increased by 17.3 ± 3.0 U/L upon vineyard grazing (p &lt; 0.001), reflecting liver storage of copper. We also discovered that the dynamics of molybdenum in sheep plasma are strongly affected by exposure to copper, suggesting a possible adaptation mechanism. Overall, our results suggest that winter grazing of sheep in organic vineyards is reasonably safe, but that care should be taken about grazing period duration. More research should be conducted with respect to long-term copper accumulation, spring and summer grazing, and possible protective mechanisms against copper chronic poisoning.

The degree of maternal nutrient restriction during late gestation influences the growth and endocrine profiles of offspring from beef cows

Context Cow–calf operations in Argentina are managed under extensive grazing condition and the quality of forages is often poor during the second half of gestation. The severity of nutrient restriction in bovine gestation, caused by seasonal pasture production, often results in poor production traits in progeny. Aims The objective of the current study was to determine whether different levels of maternal nutrient intake in beef cows during late gestation affect fetal and postnatal growth, glucose metabolism, and insulin-like growth factor 1 (IGF1) concentrations in offspring of beef cattle. Methods At 180 ± 4 days of gestation, multiparous Angus cows (n = 56) were blocked by bodyweight (BW) and expected calving date, and assigned to pens (2 or 3 cows/pen). Pens (n = 8 per treatment) were then randomly assigned to the following treatments: severely restricted (SR; 50% of net energy and 58% of CP requirements), moderately restricted (MR; 75% of net energy and 85% of CP requirements), or control (CON; 100% of net energy and 116% of CP requirements). Pen was the experimental unit and data were analysed by ANOVA or repeated measures analysis, as appropriate. After calving, all cows were managed in a single group until weaning. Key results Cow BW and body condition score decreased as nutritional restriction increased (P &lt; 0.05). At parturition, birth weight of calves from SR dams and MR dams was lower than that of calves from CON dams (P = 0.05; 4.9 kg and 2.1 kg respectively). Average daily gain of calves from birth to 24 days of age was higher (P = 0.01) in calves from SR dams than in calves from CON and MR dams. Calves from MR dams were lighter (P = 0.04) than were calves from SR and CON dams at weaning. Treatments did not affect milk production or composition (P &gt; 0.10) or glucose–insulin metabolism of offspring during lactation (P &gt; 0.10). Concentration of IGF1 tended to be lower in MR progeny than in SR and CON progeny during lactation (P = 0.09). Conclusions Late gestation maternal nutrient restriction, irrespective of the severity of the restriction, decreased birth weight of offspring; however, severe nutrient restriction induced early postnatal compensatory growth. Implications The severe nutritional restriction produced calves with weaning weights indistinguishable from the control cows due to early postnatal compensatory growth. However, the longer-term effects of nutritional restriction of the dam in the second half of pregnancy on metabolic and reproductive performance in replacement heifers or meat production/quality in steers is yet to be determined.

Long-Term and Carryover Effects of Supplementation with Whole Oilseeds on Methane Emission, Milk Production and Milk Fatty Acid Profile of Grazing Dairy Cows.

Simple SummaryDairy cow diets that include oils have shown potential to decrease methane emissions, which contribute to climate change. However, there is limited information on long-term interventions for animals in grazing systems. The aim of this study was to evaluate the effects of feeding oilseeds on the persistency of methane mitigation effects and milk production of dairy cows during a spring and summer grazing season. Carryover effects into autumn were studied. Eight weeks after beginning the feeding trial, cottonseed was more effective than linseed or rapeseed in decreasing methane per kilogram of ingested feed, but the mitigation effect did not persist when evaluated 11 weeks later. All oilseeds maintained milk production in spring, but in summer, milk yield was lower with cottonseed. There were no carryover effects of feeding oilseeds, once supplementation ended. Thus, adding oils to dairy cow diets through cottonseed supplementation had only a temporary effect on methane mitigation. This long-term study, conducted under grazing conditions, can help to assess how proposed interventions to mitigate methane can affect production and sustainability aspects of grazing dairy systems.Research is ongoing to find nutritional methane (CH4) mitigation strategies with persistent effects that can be applied to grazing ruminants. Lipid addition to dairy cow diets has shown potential as means to decrease CH4 emissions. This study evaluated the effects of oilseeds on CH4 emission and production performance of grazing lactating dairy cows. Sixty Holstein Friesian cows grazing pasture were randomly allocated to 1 of 4 treatments (n = 15): supplemented with concentrate without oilseeds (CON), with whole cottonseed (CTS), rapeseed (RPS) or linseed (LNS). Oilseeds were supplemented during weeks 1–16 (spring period) and 17–22 (summer period), and the autumn period (wk 23–27) was used to evaluate treatment carryover effects. Cows fed CTS decreased CH4 yield by 14% compared to CON in spring, but these effects did not persist after 19 weeks of supplementation (summer). Compared to CON, RPS decreased milk yield and CTS increased milk fat concentration in both spring and summer. In summer, CTS also increased milk protein concentration but decreased milk yield, compared to CON. In spring, compared to CON, CTS decreased most milk medium-chain fatty acids (FA; 8:0, 12:0, 14:0 and 15:0) and increased stearic, linoleic and rumenic FA, and LNS increased CLA FA. There were no carry-over effects into the autumn period. In conclusion, supplementation of grazing dairy cows with whole oilseeds resulted in mild effects on methane emissions and animal performance. In particular, supplementing with CTS can decrease CH4 yield without affecting milk production, albeit with a mild and transient CH4 decrease effect. Long term studies conducted under grazing conditions are important to provide a comprehensive overview of how proposed nutritional CH4 mitigation strategies affect productivity, sustainability and consumer health aspects.

The Relationship between Satellite-Derived Vegetation Indices and Live Weight Changes of Beef Cattle in Extensive Grazing Conditions

The live weight (LW) and live weight change (LWC) of cattle in extensive beef production is associated with pasture availability and quality. The remote monitoring of pastures and cattle LWC can be achieved with a combination of satellite imagery and walk-over-weighing (WoW) stations. The objective of the present study is to determine the association, if any, between vegetation indices (VIs) (pasture availability) and the LWC of beef cattle in an extensive breeding operation in Northern Australia. The study also tests a suite of VIs along with variables such as rainfall and Julian day to predict the LWC of breeding cows. The VIs were calculated from Sentinel-2 satellite imagery over a 2-year period from a paddock with 378 cattle. Animal LW was measured remotely using a weighing scale at the water point. The relationship between VIs, the LWC, and LW was assessed using linear mixed-effects regression models and random forest modelling. Findings demonstrate that all VIs calculated had a significant positive relationship with the LWC and LW (p &lt; 0.001). Machine learning predictive modelling showed that the LWC of breeding cows could be predicted from VIs, Julian day, and rainfall information, with a Lin’s Concordance Correlation Coefficient of 0.62 when using the leave-one-month-out cross-validation. The LW and LWC were greater during the wet season when VIs were higher compared to the dry season (p &lt; 0.001). Results suggest that the remote monitoring of pasture availability, the LWC and LW is possible under extensive grazing conditions. Further, the use of VIs and other readily available data such as rainfall can be used to predict the LWC of a breeding herd in extensive conditions. Such information could be used to increase the productivity and land management in extensive beef production. The integration of these data streams offers great potential to improve the monitoring, management, and productivity of grazing or cropping enterprises.

Effects of chestnut bark (Castanea spp.) tannin extracts on selectivity, dry matter intake, weight gain, and enteric methane emission from llamas (Lama glama) under grazing conditions in the high Andean grasslands

The present study's objective was to evaluate the effects of chestnut bark (Castanea spp.) tannin extracts on selectivity, organic matter intake, dry matter intake, weight gain, and enteric methane emissions from llamas as a mitigation strategy. The study was carried out from August to September 2016 at the Experimental Centre IVITA-Marangani-Cusco-Peru (4200 m above sea level). Twenty young female llamas (4.1 ± 0.34 years old) with an average live weight of 99.2 ± 5.21 kg at the beginning of the experiment were used. The llamas were allocated to two treatments (control and tannin). Organic matter intake was calculated from organic matter excretion and organic matter digestibility, the dry matter intake was calculated by using percentage of ash content of the diet, and methane emissions were determined using the SF6 tracer technique over seven days, while the llamas grazed 9 h per day on a native pasture dominated by Festuca rigescens and Calamagrostis amoena. The tannin group was provided with tannin extract derived from chestnut bark at a dose of 12 g/day orally before grazing. The selectivity in both groups was similar (P > 0.05), consuming 91.5 % of grasses and graminoids, 84.5 % of leaves and stems and 61.5 % of green matter. The control group's feed intake was 1614.64 g/day, while that of the Tannin group was 1624.70 g/day (P > 0.05). Weight gain at 31 days was similar for both groups (P > 0.05) (5.7 and 5.2 kg for the control and tannin groups, respectively). Enteric methane emissions were 27.35 ± 1.573 g/day for the control group and 19.32 ± 1.057 g/day for the tannin group (P < 0.001); showing the same tendency when methane emissions were compared according to llama live weight with 0.24 ± 0.012 and 0.17 ± 0.008 g/kg LW/day for the control and tannin group, respectively, (P < 0.001). It was concluded that the use of tannins in the present study reduced methane emissions by approximately 30 % without affecting selectivity, Dry matter intake, and weight gain in llamas.

PSXIV-16 Performance, carcass, wholesale, and retail cuts yield of lambs reared under thermal stress in grazing conditions and slaughtered at two body weights

Abstract Lamb production in tropical areas is conducted under heat stress in extensive grazing conditions of naturalized pastures (NP). The average daily gain (ADG) and yields of hot (HCY) and cold (CCY) carcass, wholesale cuts (WSC); neck (N), shoulder (SL), ribs 5–12 (RIB), loin (LN) and leg (LG), and detail cuts (DTC); shoulder chops (SCH), french chops (FCH), ribs (RS), back leg (BL) and shanks (SH) of 12 lambs (X = 19.4 kg) rotationally grazed (3 d occupation and 24 d resting period) for 154 or 238 d were determined. The Lambs grazed &amp;gt;8 h NP, grass hay and water were offered ad libitum, 150 g/d of a supplement (12% CP), and mineral blocks. Weekly weights were used to determine ADG. Lambs were slaughtered at 22 (SW1) or 35 kg (SM2) to determine HCY and CCY, and WSC and DTC yield as % of cold carcass weight. Performance data was analyzed as a randomized experimental (CRD) design over time. Carcass and cut yields data were analyzed as a CRD with 6 replicates per treatment. Lambs fed during 238-d had similar ADG than those fed 154-d (68.14 vs.47.74 g/d). SW1 and SW2 had similar percentages of HCY (35.21 vs. 38.14) and CCY (34.48 vs. 37.40). The WSC as % of cold carcass weight, N (6.43 vs. 7.06), SL (29.95 vs. 30.20), RIB (16.10 vs. 16.95), LN (10.84 vs. 11.33) and LG (36.51 vs. 34.44) were similar for SW1 and SW2. Yield of SCH and SH was lower (P &amp;lt; 0.05) for SW1 (15.80 and 8.11) than SW2 (23.00 and 9.11), but FCH (8.49 vs. 8.57), RS (6.89 vs. 7.00) and BL (36.52 vs 34.45) were similar. In summary, lambs slaughtered at 35 kg improved the retail cut yield, but did not influence ADG, HCY, CCY, and WCY compared to lighter lambs.