Energy expenditure of walk in grassland for small ruminants

Habitat Selection by Free-Grazing Sheep in a Mountain Pasture

For centuries, mountain grasslands have been part of the grazing cycle of sheep and cattle in extensive management systems in the Pyrenees; however, traditional guided herding has been, in many cases, replaced by free-ranging flocks at these pastures. The goal of this study was to analyze the grazing behavior of free-ranging sheep in mountain pastures using GPS-based tracking systems and Geographic Information Systems. During the summer seasons of 2019, 2020, and 2021, a transterminant flock of free-ranging sheep was tracked with GPS devices attached to collars at the mountain pastures of Collarada mountain (Central Pyrenees, Spain). Preferences for grazing on certain geomorphological features (slope, aspect, and altitude) and different plant communities present in the area were evaluated using the Manly's standardized preference index. The results show that sheep prefer altitudes between 2400 and 2600 m; SE-, SW-, and E-facing sites; and slopes under 20%. The preferred pastures were Festucion eskiae, Primulion intricatae, and Nardion strictae; however, they reject Festucion scopariae communities. This study demonstrates the effectiveness of GPS and GIS technologies in monitoring free-ranging sheep activity, providing valuable data for enhancing pastoral practices and ensuring sustainable pasture use.

Taste agents as modulators of the feeding behaviour of grazing yaks in alpine meadows

Feeding behaviour plays a significant role in promoting good animal health and welfare. It is also reflective of the quality and quantity of available feed. In fact, grazing livestock do not select their feed randomly, rather their behaviour is influenced by the texture, taste, and smell of each pasture species. Although taste agents are often used to modify feed intake for captive livestock, the effect on the feeding behaviour of grazing livestock has not yet been extensively evaluated in native grasslands. To address this gap in knowledge, herein, we sprayed three types of taste agents-salty (SA), sweet (SW), and bitter (BT)-on alpine meadows to investigate their effect on the grazing behaviour of yaks (Bos Grunniens) on the Qinghai-Tibetan Plateau (QTP). Behavioural observations showed that grazing was concentrated primarily in the morning and afternoon, while ruminating/resting peaked at noon; however, the diurnal behavioural patterns of grazing yaks were not affected by the taste agents. Application of the SA agent significantly increased the yaks' grazing time, bites per minute, bites per step, time per feeding station, and steps per feeding station, while significantly reducing walking time, steps per minute, and number of feeding stations per minute. Meanwhile, application of the SW agent significantly increased the yaks' time per feeding station, however, significantly reduced the steps per minute and number of feeding stations per minute. In contrast, the BT agent significantly increased the yaks' walking time, steps per minute, and number of feeding stations per minute, while significantly reducing grazing time, bites per minute, bites per step, and time per feeding station. Application of the SA agent also significantly increased the intake of favoured, edible, and inedible forage, while the SW agent improved inedible forage intake, however, had a more subtle effect on favoured and edible forage intake. Meanwhile, the BT agent had an inhibitory effect on grazing intake. Hence, the structural equation model suggested that taste agents may directly or indirectly influence grazing behaviour by regulating feeding behaviour. Our findings provide a theoretical basis for using taste agents in grasslands to control the grazing behaviour of livestock and provide a method to promote the stability of grassland communities, while mitigating the degradation of grasslands in the QTP.

Are winter rangelands enough to satisfy the nutritional requirements of late-gestation transhumant goats in Patagonia?

Transhumant herds graze across two different rangeland types according to the season. Winter rangelands differ from summer rangelands in the amount and quality of available fodder, with the former being the less productive. In cold areas, winter rangeland has low forage quality where goats may suffer severe nutritional restrictions during gestation which lead to significant reproductive losses in the form of abortions and perinatal losses. In Argentinian northern Patagonia, the transhumant Criollo goat is a dual-purpose breed, producing both meat and cashmere and grazing on winter rangelands where they complete their reproductive cycle. Our objective was to evaluate to what extent the winter rangelands of northern Argentine Patagonia satisfy the nutritional requirements needed by Criollo transhumant goats during late gestating. We evaluated a study between 2010 and 2012 where we analysed the body weight and body condition score of the goats reaching the winter rangelands and before kidding. We also analysed the botanical composition of their diet, the quality forage (metabolizable energy, crude protein and digestibility) contribution offered by the species and the proportions of the nutritional requirements of the goats during the last third of gestation. Significantly, we found a decrease in body weight and body condition score in late gestation. In 2010, the goats’ diet showed a nutritional deficiency value of 0.6 Mcal/day metabolizable energy and 30.43 g/day crude protein; in 2011, a deficiency of 0.77 Mcal/day metabolizable energy and 65.48 g/day crude protein; and in 2012, a deficiency of 0.75 Mcal/day metabolizable energy and 55.41 g/day crude protein. Forage present 51, 52 and 48% digestibility in each year, respectively. We conclude that forage quality in winter rangelands in Argentinean Patagonia is not high enough to satisfy the nutritional requirements of Criollo transhumant goats during the last third of gestation. We recommend 550 g/day of an 80:20 mixture of corn:soy expeller supplementation during late gestation.

Estimation of Grazing Activity of Dairy Goats Using Accelerometers and Global Positioning System

The recent development of advanced electronic sensors to monitor and record animal grazing activity provides a real opportunity to facilitate understanding of their behavioral responses. This study aimed to characterize the grazing activity and protein−energy requirements of grazing dairy goats in a Mediterranean woodland in northern Morocco by combining two sensors, the Global Positioning System (GPS) and three axis accelerometers. An experiment was conducted in a representative woodland with eight dairy goats. Measurements were undertaken during the three main grazing seasons (spring, summer, and autumn) for two consecutive and contrasting years. Grazing activity parameters were assessed using GPS collars and leg position sensors. The results showed that grazing time was higher in spring (57% and 59%) than in summer (39% and 36%) and autumn (41% and 45%), respectively, for the dry and wet years (p < 0.001). During the two studied years, the daily horizontal distance traveled by the goats increased from spring (about 4.5 km) to summer (about 6.5 km) and autumn (about 7.4 km), while greater daily vertical distances were recorded over similar distances during summer−autumn. Several protein−energy intakes that were insufficient to cover the requirements of the grazing goats were recorded, especially in summer. The combination of GPS collars and accelerometers contributed to a better understanding of the grazing activities of dairy goats in the studied Mediterranean woodland. These findings provide useful data on the protein−energy balances of dairy goats and offer additional information that could be useful for herders and managers to enhance goat-feeding strategies and guarantee high-performance in the semi-extensive traditional goat farming system.

Using GPS Collars and Sensors to Investigate the Grazing Behavior and Energy Balance of Goats Browsing in a Mediterranean Forest Rangeland

The Global Positioning System (GPS) and sensors technologies are increasingly used to study the grazing behavior of animals. This work was conducted to understand the grazing behavior and energy balance of goats browsing in forest rangeland using GPS and sensors technologies. Forage availability was estimated using the quadrat method during three grazing seasons. Simultaneously, eight indigenous goats were selected to explore their feeding behavior, grazing activities, and energy requirements. The experimental goats were fitted with GPS collars and leg sensors to monitor their grazing activities. At the same time, direct observation was used as a method to study their feeding behavior. Forage availability was higher during spring compared to the summer and autumn seasons. Goats recorded the highest biting rate during summer and autumn (about 22 bites/min). The highest intake rate was recorded during spring (5.6 g DM/min). During spring, goats spent most of their time on grazing (48%) in contrast to the summer and autumn (<31%; p < 0.001). They prolonged their lying down time in summer at the expense of standing duration. The time devoted exclusively to grazing (eating) was longer in spring. Walking time in summer and autumn was longer than in spring (p < 0.001). During summer and autumn, the energy balance of goats under grazing conditions was in deficit. Using GPS collars and leg sensors appears to be a useful and easily replicable method to explore and understand the seasonal changes in the grazing areas and activities of goats in a mountainous region. The results could help goat herders and managers to develop feeding and grazing systems while increasing the performance of goats in the Mediterranean forest rangeland.

Quantifying energetic costs and defining energy landscapes experienced by grizzly bears

Animal movements are major determinants of energy expenditure and ultimately the cost–benefit of landscape use. Thus, we sought to understand those costs and how grizzly bears (Ursus arctos) move in mountainous landscapes. We trained captive grizzly bears to walk on a horizontal treadmill and up and down 10% and 20% slopes. The cost of moving upslope increased linearly with speed and slope angle, and this was more costly than moving horizontally. The cost of downslope travel at slower speeds was greater than the cost of traveling horizontally but appeared to decrease at higher speeds. The most efficient walking speed that minimized cost per unit distance was 1.19±0.11 m s−1. However, grizzly bears fitted with GPS collars in the Greater Yellowstone Ecosystem moved at an average velocity of 0.61±0.28 m s−1 and preferred to travel on near-horizontal slopes at twice their occurrence. When traveling uphill or downhill, grizzly bears chose paths across all slopes that were ∼54% less steep and costly than the maximum available slope. The net costs (J kg−1 m−1) of moving horizontally and uphill were the same for grizzly bears, humans and digitigrade carnivores, but those costs were 46% higher than movement costs for ungulates. These movement costs and characteristics of landscape use determined using captive and wild grizzly bears were used to understand the strategies that grizzly bears use for preying on large ungulates and the similarities in travel between people and grizzly bears that might affect the risk of encountering each other on shared landscapes.

Sheep and goat feeding behavior profile in grazing systems

 Feeding behavior analysis provides information about the relationships between animals and pastures. Therefore, this review aims to describe some aspects of the feeding behavior profiles of both sheep and goats in grazing systems. The structure of the pasture is a key factor in the feeding behavior of grazing animals. The amount of feed consumed in a given period of time is affected by the number of meals, duration and velocity of swallowing, changes in grazing time, bite rate, bite weight, and quality of ingested forage. The different phenological stages of forage also influence the animals’ strategies to optimize their intake, which consequently changes their behavioral activities. Sheep and goats tend to be more selective than cattle, and young animals are more selective than older animals; this selectivity characteristic is one of the most important aspects to be observed in pasture management. According to the degree of selectivity, the animals will intake forages of higher or lower nutritive quality. In addition, the intensity and distribution of their daily activities (grazing, ruminating, and resting) are influenced by several factors, such as the availability and nutritive value of the pasture, its management, the animal activity in the group, and the predominant climatic conditions of the region.

Hepatic transcriptome profile of sheep (Ovis aries) in response to overgrazing: novel genes and pathways revealed

BACKGROUND

Overgrazing is a major factor that causes steppe degradation in Inner Mongolian, resulting in extensive ecosystem damage. Scarcity of grass means sheep are smaller and therefore mutton and cashmere production is greatly reduced, which has resulted in massive annual economic losses. Liver is the primary metabolic organ in mammals. It is also the key source of energy supply and detoxification of metabolites in animals, has a close relationship with animal growth. However, investigations on the responses of sheep induced by consequence of overgrazing, particularly those relating to liver-related molecular mechanisms and related metabolic pathways, remain elusive.

RESULTS

The body weight daily gain of sheep, immune organ indices (liver and spleen), and serum parameters related to immune response, protein synthesis and energy supply (IgG, albumin, glucose and non-esterified fatty acid) were significantly lower in the overgrazing group. Other serum parameters including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bilirubin, blood urea nitrogen and interleukin-6 were significantly higher in the overgrazing group. For the RNA-Seq results, we identified approximately 50 differentially expressed genes, of which half of were up-regulated and the other half were down-regulated (overgrazing group versus light grazing group). Bioinformatics analysis identified two enriched KEGG pathways including peroxisome proliferator-activated receptor (PPAR) signaling pathway (related to lipolysis) and ECM-receptor interaction (related to liver injury and apoptosis). Additionally, several of the down-regulated genes were related to detoxification and immune response.

CONCLUSIONS

Overall, based on the high-throughput RNA sequencing profile integrated with the results of serum biochemical analyses, consequences of lower forage availability and quality under overgrazing condition induced altered expression levels of genes participating in energy metabolism (particularly lipid metabolism) and detoxification and immune responses, causing lipolysis and impaired health status, which might be key reasons for the reduced growth performance of sheep. This investigation provides a novel foundation for the development of sheep hepatic gene interactive networks that are a response to the degraded forage availability under overgrazing condition.

Validity of Micro-Data Loggers to Determine Walking Activity of Turkeys and Effects on Turkey Gait

Accelerometers have the potential to provide objective, non-invasive methods for detecting changes in animal behavior and health. Our objectives were to: (1) determine the effects of micro-acceleration data loggers (accelerometers) and habituation to accelerometers on turkey gait and health status, (2) determine age-related changes in gait and health status, and (3) assess the validity and reliability of the accelerometers. Thirty-six male commercial turkeys were randomly assigned to one of five groups: accelerometer and habituation period (AH), accelerometer and no habituation period (AN), VetRap bandage (no accelerometer) and habituation period (VH), bandage (no accelerometer) and no habituation period (VN), and nothing on either leg (C). Health status and body condition were assessed prior to video-recording birds as they walked across a Tekscan® pressure pad at 8, 12, and 16 weeks to determine effects of treatment on number of steps, cadence, gait time, gait distance, gait velocity, impulse, gait cycle time, maximum force, peak vertical pressure, single support time, contact time, step length, step time, step velocity, stride length, total double support time, and duty factor. Accelerometer validity and reliability were determined by comparing the number of steps detected by the accelerometer to the number of steps determined from video recordings. Several age-related changes in turkey gait were found regardless of habituation including a slower cadence at 16 weeks, shorter gait distance at 8 weeks, and slower gait velocity at 16 weeks. When comparing bandaged vs. unbandaged limbs, both treatment and age-treatment interactions were found depending on the gait parameter. Accelerometer validity and reliability were affected by both age and treatment. False discovery rate increased, while accuracy and specificity decreased with age. Validity and reliability were lowest for non-habituated birds (AN and VN). Results demonstrated that micro-data loggers do not adversely affect turkey health status, but habituation to wearing accelerometers greatly affects accelerometer reliability and validity. Accelerometer validity and turkey gait are also greatly affected by the age of the turkeys.

Timing of head movements is consistent with energy minimization in walking ungulates

Many ungulates show a conspicuous nodding motion of the head when walking. Until now, the functional significance of this behaviour remained unclear. Combining in vivo kinematics of quadrupedal mammals with a computer model, we show that the timing of vertical displacements of the head and neck is consistent with minimizing energy expenditure for carrying these body parts in an inverted pendulum walking gait. Varying the timing of head movements in the model resulted in increased metabolic cost estimate for carrying the head and neck of up to 63%. Oscillations of the head-neck unit result in weight force oscillations transmitted to the forelimbs. Advantageous timing increases the load in single support phases, in which redirecting the trajectory of the centre of mass (COM) is thought to be energetically inexpensive. During double support, in which-according to collision mechanics-directional changes of the impulse of the COM are expensive, the observed timing decreases the load. Because the head and neck comprise approximately 10% of body mass, the effect shown here should also affect the animals' overall energy expenditure. This mechanism, working analogously in high-tech backpacks for energy-saving load carriage, is widespread in ungulates, and provides insight into how animals economize locomotion.

Overgrazing induces alterations in the hepatic proteome of sheep (Ovis aries): an iTRAQ-based quantitative proteomic analysis

Background

The degradation of the steppe of Inner Mongolia, due to overgrazing, has resulted in ecosystem damage as well as extensive reductions in sheep production. The growth performance of sheep is greatly reduced because of overgrazing, which triggers massive economic losses every year. The liver is an essential organ that has very important roles in multiple functions, such as nutrient metabolism, immunity and others, which are closely related to animal growth. However, to our knowledge, no detailed studies have evaluated hepatic metabolism adaption in sheep due to overgrazing. The molecular mechanisms that underlie these effects remain unclear.

Methods

In the present study, our group applied isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analysis to investigate changes in the protein profiles of sheep hepatic tissues when nutrition was reduced due to overgrazing (12.0 sheep/ha), with the goal of characterizing the molecular mechanisms of hepatic metabolism adaption in sheep in an overgrazing condition.

Results

The body weight daily gain of sheep was greatly decreased due to overgrazing. Overall, 41 proteins were found to be differentially abundant in the hepatic tissue between a light grazing group and an overgrazing group. Most of the differentially expressed proteins identified are involved in protein metabolism, transcriptional and translational regulation, and immune response. In particular, the altered abundance of kynureninase (KYNU) and HAL (histidine ammonia-lyase) involved in protein metabolic function, integrated with the changes of serum levels of blood urea nitrogen (BUN) and glucose (GLU), suggest that overgrazing triggers a shift in energy resources from carbohydrates to proteins, causing poorer nitrogen utilization efficiency. Altogether, these results suggest that the reductions in animal growth induced by overgrazing are associated with liver proteomic changes, especially the proteins involved in nitrogen compounds metabolism and immunity.

Conclusions

This provides new information that can be used for nutritional supplementation to improve the growth performance of sheep in an overgrazing condition.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-016-0111-z) contains supplementary material, which is available to authorized users.

Effects of housing systems and the diet supplements on the slaughter value and concentration of mineral elements in the loin muscle of lambs

The objective of this study was to investigate the effect of maintenance system as well as the effect of Se, Zn, and vitamin E supplementation of ram-lambs on the slaughter value and concentration of mineral elements in the loin muscle of lambs. The experiment was conducted on 72 Polish Merino ram-lambs divided into three groups: group C, indoor with no supplement, 19 lambs; S, indoor with supplement, 23 lambs; G, outdoor with no supplement, 30 lambs. From birth all the lambs were maintained indoor with their dams and then weaned at the age of 8 weeks. The rams from group C and S were placed in individual straw-bedded pens and fattened individually with concentrate mixture offered ad libitum until the age of 16 weeks. The lambs from group G were grazed every day from May to July (2 months). During the fattening period each lamb from the supplemented group S was administered per os 1 mL 0.1% Na₂SeO₄ (Se, 0.42 mg), 3 mL 10% ZnSO₄ (Zn, 68 mg), and 1 mL premix protect vitamin E (0.1 g α-tocopherol, 5 mg lysine, 5 mg methionine) daily. A comparison of half carcasses across the groups has shown no difference between the control group and the one with supplements, while the weight of half carcasses in the grazing group was smaller in comparison with groups C and S (p<0.001). The meat content in the pelvic limb showed no differences across all groups under study. The pelvic limb of grazing lambs contained less fat compared to the control and supplemented groups (p<0.001). The concentrations of Se and Zn in the blood plasma of ram-lambs from the supplemented group were significantly higher than for the control and grazing lambs. Inorganic Se and Zn supplementation with vitamin E to the diet of lambs increased Se and Zn levels in loin muscle (p<0.001) to 0.46 μg/g and 32.9 μg/g in fresh tissue, respectively.

Incorporating farmed goats into sustainable rangeland grazing systems in southern Australia: a review

The recent trend to farming or re-domestication of feral goats poses serious questions for the ecological sustainability of the semiarid and arid rangelands of southern Australia. This paper reviews aspects of the biology and grazing habits of goats, and aspects of the Australian goat industry, relevant to their sustainable management in livestock enterprises. Key factors identified include high fertility and fecundity even under low seasonal rainfall conditions and a generalist feeding strategy. Adverse consequences for rangeland condition can be expected if seasonal or market conditions result in an imbalance between population growth and turnoff, resulting in high grazing pressures. Given the limited control of the reproductive process at the current stage of the development of goat farming, strategies aimed at ensuring continuity of sale of goats (e.g. on-property feed lots or supply chain and market development) will be important in ensuring that imbalances are avoided. Conservative stocking rates and use of seasonal risk management tools are also particularly relevant. The major research and development needs identified by this review, from a resource management perspective, concern the appropriate dry sheep equivalent rating for goat classes based on age, sex and reproductive status, the extent and consequences of heterogeneity of grazing in space, time, and across forage species, and development of means of establishing sustainable stocking rates based on the use of all available forage sources, including browse.

Effect of walking stress on growth, physiological adaptability and endocrine responses in Malpura ewes in a semi-arid tropical environment

Sheep in hot semi-arid environments are mostly reared using extensive systems. In addition to thermal stress and feed scarcity, the animals need to walk long distances for grazing in this ecological zone. A study was conducted to assess the effect of long-distance walking on adaptive capability in terms of physiological, biochemical and endocrine responses in Malpura ewes. Fourteen adult Malpura non-pregnant ewes weighing between 33 and 35 kg were used in the study. The ewes were randomly allocated into two groups of seven animals each: GI (n = 7; Control), and GII (n = 7; walking stress). The animals were stall-fed with a diet consisting of 70% roughage and 30% concentrate. Both GI and GII ewes had uniform access to feed and water. The walking stress group (GII) ewes were made to walk 14 km in two spans between 0900 and 1500 hours with 1 h 30 min for each span (7 km) of walking. The ewes subjected to walking stress (GII) were prevented from grazing by applying a face mask made of cotton thread. The study was conducted for a period of two estrous cycles (35 days) during the autumn season (October-November). Physiological responses were recorded twice daily at 0800 and 1400 hours at weekly intervals. Blood samples were collected from the jugular vein at weekly intervals to study the effects of walking stress on blood biochemical and endocrine parameters. The results indicate that walking stress had significant (P < 0.05) influence on body weight, average daily gain, respiration rate (RR), rectal temperature (RT), haemoglobin (Hb), packed cell volume (PCV), plasma glucose, calcium, phosphorus, aspartate amino transferase (AST), alanine amino transferase (ALT), tri-iodo-thyronine (T(3)), thyroxin (T(4)), and cortisol. However, walking stress did not influence the reproductive hormone levels. The significant changes in RR, RT, plasma cortisol, T(3) and T(4) show that Malpura ewes have the capability to adapt to long-distance walking, and that adrenal and thyroid gland hormones play a significant role in such adaptation.