Selective behavior of Creole goats in response to the functional heterogeneity of native forage species in the central Monte desert, Argentina

How plant traits respond to and affect vertebrate and invertebrate herbivores-Are measurements comparable across herbivore types?

Despite plants realistically being affected by vertebrate and invertebrate herbivores simultaneously, fundamental differences in the ecology and evolution of these two herbivore guilds often means their impacts on plants are studied separately. A synthesis of the literature is needed to understand the types of plant traits examined and their response to, and effect on (in terms of forage selection) vertebrate and invertebrate herbivory, and to identify associated knowledge gaps. Focusing on grassland systems and species, we found 138 articles that met our criteria: 39 invertebrate, 97 vertebrate and 2 focussed on both vertebrate and invertebrate herbivores. Our study identified invertebrate focussed research, research conducted in the Southern Hemisphere and research on nondomesticated herbivores was significantly underrepresented based on our search and should be a focus of future research. Differences in study focus (trait response or trait effect), along with differences in the types of traits examined, led to limited opportunity for comparison between the two herbivore guilds. This review therefore predominantly discusses the response and effect of plant traits to each herbivore guild separately. In future studies, we suggest this review be used as a guide for trait selection, to improve comparability and the broader significance of results.

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.

Selection of Forage Resources by Juvenile Goats in a Cafeteria Trial: Effect of Browsing Experience, Nutrient and Secondary Compound Content

Simple Summary

Grazing/browsing goats ingest a diverse diet selected from the forage resources available in the range/paddock intending to meet their nutritional requirements. Intake and selection of any given forage can be modified by several factors, such as its nutrient content, including secondary compounds, as well as its biomass availability in the environment. The animal’s previous browsing experience can also be an important factor driving intake and selection. Therefore, the present study evaluated all these factors as well as their interaction. The results showed that the goats’ browsing experience guided the selection and intake towards those forage resources of better nutritional quality when there was no restriction in forage supply, as is the case for cafeteria trials. Goats with browsing experience showed their ability to limit secondary compounds and optimize their selection and intake for plants with better digestibility. This cafeteria protocol made it possible to identify the selection and consumption pattern of plant species with limited availability in the natural vegetation. This methodology could help identifying the forage resources that may be useful for small ruminant feeding, versus those resources that are not consumed by goats despite having a suitable chemical composition and in vitro digestibility or a high abundance.

Abstract

We evaluated the effect of browsing experience, nutritional quality and secondary compounds of forage resources, and the interaction between these factors on the selection and intake of goats in a cafeteria trial. Twelve juvenile Criollo goats from 7 to 9 months of age, weighing 22 ± 3 kg, were divided into two groups: (a) browser goats group (n = 6, BG), and (b) naïve goats group (n = 6, NG), formed according to their previous browsing experience (with and without, respectively). Animals were housed in individual pens. The cafeteria experiment lasted 21 days considering pen adaptation, foliage adaptation, and measurements, which included the selection index (SI) of experimental forage resources (Chesson’s alpha) and their dry matter intake (DMI/Kg^0.75), using a multiple Latin square design. Furthermore, correlation and regression analyses were used to assess the relationship between the aforementioned factors. The NG did not show any selection pattern, while the BG selected Piscidia piscipula and Senegalia gaumeri (p = 0.0002). The BG consumed smaller amounts of secondary compounds compared to NG (p = 0.0001). In the BG, the flavonoids affected negatively their selection (R² = 97.51, p = 0.0001), while the DMI was affected by in vitro DM digestibility and flavonoids (R² = 99.85; p = 0.0001). For the NG, the crude protein and organic matter contents were associated with DMI, but none had a significant relationship with SI. The BG selected and consumed forages with suitable nutritional quality avoiding those with high content of secondary compounds such as flavonoids. Conversely, NG did not show a clear pattern for their selection or intake.

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.

Effects of Replacing Grass with Foliage on Growth Rate and Feed Intake in Goats-A Systematic Review and Meta-Analysis

Small ruminants such as goats have a higher preference for browse species than cattle and sheep. In a meta-analysis of 42 papers describing 117 experimental treatments found by a search performed in June 2021 in PubMed and Web of Knowledge, we examined the general effect of including foliage in the diet of goats, replacing grasses, on dry matter intake and average daily weight gain. The inclusion requirement for a paper was that it described a controlled trial with a control diet of grass and with grass replaced by foliage in the experimental diet. Publication bias was estimated by calculating the Fail-safe n. Random effects analyses were conducted, using effect size calculated as Hedges' d. The results showed that inclusion of foliage increased feed intake (Hedges' d = 1.350, SE = 0.388) and average daily weight gain (Hedges' d = 1.417, SE = 0.444) compared with a grass-based control. The positive effect of foliage inclusion on dry matter intake was associated with lower neutral detergent fiber (NDF) and higher crude protein (CP) in the foliage than in the grass it replaced. The positive effect on average daily weight gain was associated with higher CP concentration in the foliage than in grass. Foliage inclusion level showed a quadratic relationship with dry matter intake, with maximum dry matter intake achieved at a level of 50-60%. There was wide variation between the studies reviewed, and this variation was not reduced by subgroup analysis based on different kinds of foliage. In conclusion, the addition of foliage to goat diets can increase feed intake and daily weight gain, as an effect of the dietary preferences of goats and of generally higher nutritional value in foliage species compared with natural/semi-natural grass species.

Stocking Rate Has No Confounding Effect on the Use of Internal and Inert Markers to Predict Botanical Composition, Diet Quality, Degradability and Passage Rate Kinetics in Sheep

Simple Summary

Internal markers are components of diets recovered to different degrees in faeces of animals. These feed components maybe helpful in predicting diet selection, nutrient intake and digestibility in animals. The development of sustainable grazing management and practices to prevent the depletion of natural grasslands as a result of overgrazing depends on the knowledge of feed intake, chemical and botanical composition of diets selected and consumed by ruminants. Determination of the botanical composition of diets selected by free ranging ruminants by visual observation is time consuming and tedious, while the use of oesophageal cannulated animals is invasive and impairs animal welfare. Therefore, it is imperative to use non-invasive methods, such as internal markers to predict feed preferences and composition of diets that ruminants consume. However, it is unclear if the accuracy of results obtained using internal markers is confounded by other factors, such as stocking rate, which is expected to determine the availability and botanical composition of pasture, which, in turn, may exert its influence on the diet selected and consumed by grazing animals. The findings of this study, however, showed that stocking rates did not affect diet selection and nutrient intake in sheep, while a combination of internal markers can be used to estimate the quality of diet selected by animals under cafeteria feeding conditions, regardless of the stocking rate used. Thus, the use of modified acid detergent fibre, acid insoluble ash and acid detergent lignin contents in feeds achieved high accuracy and precision in estimating diets selected by sheep. This approach serves as a proof of concept that these markers can be also used in free ranging animals.

Abstract

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

Effect of leaf type on browse selection by free-ranging goats in a southern African savanna

Broad- and fine-leaved woody species respond to seasonal changes from wet to dry season differently. For example, broad-leaved species shed their leaves earlier, while fine-leaved species, especially acacias retain green foliage well into the dry season. These differences are expected to result in variation in selection of broad- and fine-leaved woody species as browse by free-ranging goats. We tested the hypothesis that free-ranging goats select broad-leaved woody species more than fine-leaved species during wet (growth) season and fine-leaved woody species more than broad-leaved species during dry season. In addition, we tested if broad- and fine-leaved woody species had different foliar dry matter digestibility and chemical composition (crude protein, neutral detergent fibre, acid detergent fibre, total phenolics and condensed tannins concentration). Free-ranging goats were observed foraging on broad- and fine-leaved woody species over a two-year period (2014 and 2015) during three seasons: early wet (October/November), late wet (February/March) and dry (May/June). Ivlev's selectivity or Jacob's index (Ei) was calculated for five woody species (two broad-leaved and three fine-leaved) browsed by goats during wet and dry season. Jacob's selectivity index was higher for broad-leaved (Ziziphus mucronata and Searsia (Rhus) tenuinervis) than fine-leaved woody species (Acacia nilotica, Acacia karroo and Dichrostachys cinerea) during wet season. However, the trend was reversed during dry season with fine-leaved species having higher Jacob's selectivity index than broad-leaved species. Leaf dry matter digestibility and chemical composition was similar between broad- and fine-leaved woody species throughout the year. We conclude that goats selected broad-leaved woody species during wet season when browse was plentiful and then switched to fine-leaved species which retained leaves during dry season.

Small Ruminant Production Based on Rangelands to Optimize Animal Nutrition and Health: Building an Interdisciplinary Approach to Evaluate Nutraceutical Plants

The plant kingdom can influence the productivity and health of herbivores at different levels. However, demonstrating this process in a scientific manner entails substantial endeavors from different disciplines. In the present review, we will describe the features of a native vegetation system traditionally used by small ruminants and use its particularities to build an interdisciplinary approach to evaluate the nutraceutical properties of plants. Initially, we will establish the context of the low deciduous forest (LDF), considering some botanical and nutritional aspects, as well as the presence of plant secondary compounds (PSC) and gastrointestinal nematodes (GIN). Furthermore, we will focus on coevolutionary aspects that undoubtedly shaped the plants-nutrients-PSC-GIN-herbivore relationship. In addition, the concept of nutraceutical will be discussed to provide clarity and aspects to be considered for their evaluation. Then, ethological, agronomical, nutritional, PSC, parasitological and animal species issues are deepened placing emphasis on methodological approaches. Special focus is given to condensed tannins, as they are the fourth largest group of PSCs and the most studied in livestock sciences. Validation of the nutraceutical properties of plants from native vegetation systems should be seen as a process derived from many scientific disciplines that feed into each other in a cyclic manner.

Foraging Behavior of Goats Browsing in Southern Mediterranean Forest Rangeland

Simple Summary

Grazing goats in forests is an ancestral practice in the Mediterranean region. This study aims to assess the seasonal variations in the feeding behavior of goats browsing in the Mediterranean forest rangeland of Northern Morocco for two years. The goats’ diet was largely composed of woody species. Overall, the smaller the bite mass, the higher the biting rate, leading to an increased instantaneous intake rate. During the dry season, goats tend to compensate for the low intake rate by extending daily grazing time, thus reducing the sensitivity of intake rates to forage availability. A particular high selection of cork oak was observed over seasons. The higher diet diversity was recorded during summer and fall compared to the spring. Nevertheless, it should be remembered that the diet selection of goats is ultimately influenced by the herder’s decisions. Results confirm the high adaptability of goats to the seasonality of complex Moroccan forest rangelands.

Abstract

Mediterranean forest rangelands offer an important feed source for goats. Concerns about grazing strategies and management schemes in order to ensure the rangeland sustainability of Southern Mediterranean forest have revived interest in the foraging behavior of goats. This study was conducted to investigate the seasonal changes of feeding behavior of grazing goats in the Southern Mediterranean forest rangeland of Northern Morocco during two consecutive years beginning in 2016. The direct observation method was used to compare diet composition, intake rate, and diet selectivity of goats during three seasons (spring, summer, and fall). Bite mass of each plant species selected by goats was estimated using hand-plucked simulation. The optimal foraging theory was used as a tool to explain the goats foraging decisions. Bite mass range was extremely wide and varied seasonally. The goats’ diet was largely composed of Cistus spp., Lavandula stoechas, Quercus spp., and Myrtus communis. The result shows that the smaller the bite mass, the higher the biting rate, leading to increased short term intake rates. The selection of various plant species during fall and summer enlarged the diet diversity of goats. As expected, goats preferred trees and some shrubs despite their low availability. Consequently, the most available species is not necessarily the most positively selected. Particular high and positive selection of Quercus suber was observed over seasons. The outcomes confirm the high adaptability and ability of goats to select a woody species across seasons. Knowledge about forage availability and the feeding behavior of goats could be used as the first guide for rangeland managers to ensure herd and forest sustainability.

Ingestive behavior and feeding preference of goats reared in degraded caatinga

Abstract This study aimed to assess the ingestive behavior and feeding preference of goats reared in degraded Caatinga (dry tropical forest) during three seasons: transition (rainy-dry), dry, and rainy seasons. The experiment was carried out at the UFPB Experimental Station in São João do Cariri, PB, Brazil. Six male goats kept on pasture with an area of 3.2 hectares were used. The animals were assessed through continuous visual observation. The experimental design was completely randomized, with three treatments (rainy-dry, dry, and rainy seasons) and six replications (animals). Means were submitted to the Tukey test at a 5% level. The time www.revistas.ufq.br/vet spent by animals during the transition season (rainy-dry) had to cite in the article page. similarities for the selected grasses, herbaceous/sub-shrub plants, litter, and shrub/ tree plants, except for bromeliads and cacti. The animals spent longer grazing time consuming grasses at the rainy season. During this season, marmeleiro (Croton hemiargyreus Mill. Arg.) was the most selected species in relation to catingueira (Caesalpinia pyramidalis Tul.) and pereiro (Aspidosperma pyrifolium Mart.). The time spent for grazing activity during the transition season (rainy-dry) was longer than the rainy and dry season. Goats reared extensively in the Caatinga have high plasticity in their eating habits and can behave as grazing or browsing animals.

Understanding natural behavior to improve dairy goat (Capra hircus) management systems

Public interest is stimulating farming industries to improve animal welfare in production systems. Indoor housing of ruminants has received scrutiny because of perceived intensiveness and lack of naturalness. Animal welfare has traditionally focused on health benefits (e.g., bedding management and reducing disease) and reducing negative experiences (e.g., painful husbandry practices). Recent attention to animals having "a life worth living" extends expectations to provide increased care and opportunities for positive experiences and natural behaviors. Although not all natural behaviors necessarily contribute to improved welfare, we present evidence for why many are important, and for how they can be promoted in commercial systems. Worldwide, commercial dairy goats (Capra hircus) are frequently housed in large open barns with space to move and soft bedding for lying; however, this is not sufficient to promote the range of natural behaviors of goats, which in turn suggests that commercial housing could be improved. The basis for this thinking is from the range of behaviors expressed by the Capra genus. Collectively, these species have evolved cognitive and behavioral strategies to cope with harsh and changing environments, as well as variable and limited vegetation. The rocky and often steep terrain that goats inhabit allows for predator avoidance and access to shelter, so it is not surprising that domesticated goats also seek out elevation and hiding spaces; indeed, their hoof structure is designed for the movement and grip in such rugged environments. The browsing techniques and flexibility in diet selection of wild, feral and extensively managed goats, appears to be equally important to housed goats, highlighting the need for more complexity in how and what goats are fed. Goats naturally live in small, dynamic groups, governed by complex social structures in which horns play a strong role. Commercial housing systems should consider the benefits of more natural-sized social groups and revisit the rationale behind horn removal. We suggest that cognitive stimulation is a potential welfare improvement for goats in commercial settings. Goat cognitive abilities, which enabled success in complex and variable social and physical environments, are unchallenged in uniform environments, potentially leading to negative affective states. We make suggestions for housing improvements that could be readily adopted into current systems without compromising production efficiency.

Feed resource selection by Criollo goats browsing a tropical deciduous forest

Goats browsing in a tropical deciduous forest (TDF) obtain a large proportion of their diet from a large number of plant species. Nevertheless, the goat’s feed resource selection has not been studied in such an ecosystem. This study aimed to determine whether goats browsing in a TDF display active feed resource selection. Two browsing sites were used (A = 2.2 ha and B = 2.6 ha). The effective availability (g) of all plant species available was measured for each site using 10 m × 20 m exclusion quadrants. Three non-pregnant adult goats (34.9 ± 2.4 kg liveweight) with browsing experience were observed using the continuous bite monitoring method to determine their respective dry matter intake. The selection of different plants was determined using the Jacobs’ selection index (JSI). The goats’ dry matter intake per day was 723 and 310.8 g for Sites A and B, respectively. At both browsing sites, the plant with the highest biomass availability was Gymnopodium floribundum (75.5% and 49.3% for Sites A and B, respectively). Nevertheless, the plant species most actively selected by goats were Eragrostis ciliaris at Site A (JSI = 0.99, P < 0.05) and Mimosa bahamensis at Site B (JSI = 0.96, P < 0.05). Some plant species were not consumed at Sites A and B (three and five species, respectively). In conclusion, feed resource selection was not associated with the biomass availability of the plants selected or refused. Goats were able to show active feed resource selection in the TDF, and this could change according to the characteristics of the browsing site.