Comparison of grazing behaviour, dietary overlap and performance in non-lactating domestic ruminants grazing on marginal heathland areas

During the years 2000–2001, 7 non-lactating beef cows, 40 ewes and 40 does were managed in mixed grazing on a natural heathland vegetation plot (22 ha) with 20% improved pasture (perennial ryegrass) on a hill (1000 m a.s.l.) experimental farm located in the NW of Spain. Samples of faeces and vegetation components were collected monthly to estimate diet selection, using the alkane markers, and diet overlapping level. Animals were weighed monthly to quantify live weight changes and performance of the three livestock species during different periods (spring, summer, autumn, winter) of the grazing season.

The percentage of shrubs in the diet was significantly higher in the small ruminants (ranging between 36% and 85%) than in cows (less than 25%) in any period. Gorse (Ulex gallii) and heather (Erica spp., Calluna) percentages were always significantly higher in does than in ewes, except in autumn for heather. Herbaceous component (namely grasses) was higher in cattle (75–99%) than in small ruminants (15–64%). The lowest mean dietary overlap was found between cattle and goats (50.4%), with large differences during the grazing season, ranging between 20% and 70%.

The three animal species increased their live weight in the first grazing period (spring), when the mean sward height on the improved area was higher than 6.0 cm. However, when the sward height was lower than 3.5 cm (summer–winter), cows lost weight (− 437 g/day) while ewes and goats were still able to increase their weight (29 and 5 g/day, respectively).

Therefore, it seems that small ruminants, mainly sheep, are more suitable than cattle from the vegetation utilization and animal performance points of view, as cows were unable to maintain live weight when the preferred grass availability decreases. Goats were the species that included the highest proportion of heathland vegetation components in the diet, especially gorse, although their performance was significantly lower than in sheep. In consequence, small ruminant production systems could be more sustainable than cattle. The results indicate that mixed grazing of sheep and goats could be appropriate in these vegetation communities, allowing the development of sustainable systems, in which animal performance and the efficiency of resource use are maximized.     

Effect of Simulated Browsing on Aspen Regeneration: Implications for Restoration

Aspen (Populus tremuloides Michx.) is a disturbance-dependent, fire-resilient, shade-intolerant, clonal species that is in decline throughout western North America. The objective of this study was to examine the effects of intensity and season of browsing on annual height growth of aspen suckers. The goal was to aid development of livestock grazing strategies to restore stands in decline due to excessive livestock browsing. We implemented 33 combinations of intensity and season of browse on aspen suckers in three aspen stands on Eagle Lake Range District, Lassen National Forest, California, USA, during 2003 and 2004. Greatest growth was on suckers with no terminal leader browse and ≤ 25% of biomass removed from branches. Lowest growth occurred when 90% of terminal leader length and 50% of branch biomass was removed. Growth was most negatively affected by browse on terminal leader. Growth was lowest for suckers browsed midseason only and suckers browsed both early and midseason. Occurrence of conifer in the stand overstory significantly reduced sucker growth. Managers should minimize browse on terminal leaders, midseason browse over consecutive years, and repeated browse during a growing season.     

施肥和刈割处理模拟放牧对西北针茅生长的影响

放牧是天然草地最主要的利用方式,其对于草地的影响主要是采食、践踏和排泄作用.不同畜种具有不同的牧食行为,对于草地的影响也不同.为了研究牛羊混合放牧对于西北针茅(Stipa sareptana var.krylovii)草原建群种的影响,本研究设置了对照、添加牛粪+刈割(模拟牛单牧)、添加羊粪+不刈割(模拟羊单牧)、添加...     

Reproductive and productivity traits of goats grazing Acacia cyanophylla Lindl. with and without daily PEG supplementation

A grazing experiment, conducted for 90 days compared the effect of polyethylene glycol (PEG) supplementation on postpartum reproductive traits and productivity of suckling goats grazing Acacia cyanophylla Lindl. A total of 54 native adult goats (34.4 ± 5.49 kg) were randomly allocated, 24 h after kidding, to 2 treatment groups balanced for age and the number of reared kids. Goats in both treatment groups designed C and PEG grazed in acacia for approximately 5 h every day and received each on daily basis 0.3 and 0.4 kg of hay and concentrate respectively. In addition, goats in treatment PEG were initially supplemented with 10 g/day of PEG and this supplement was then increased to 20 g /goat/day over the last 60 days of the trial. Goats receiving PEG tended (P > 0.05) to spend more time browsing acacia than those in treatment C. There were no treatment effects on live weight change of the goats, growth of their kids until 90 days of age or composition of their milk in terms of fat, protein and urea contents. Similar proportions of 74.1 and 77.8% of goats resumed postpartum ovulation with a mean ovulation rate of 1.50 ± 0.61 and 1.67 ± 0.47 (P > 0.05) in respectively the PEG and C treatments. PEG supplementation was associated with an increase (P < 0.05) in ovulation rate at the second postpartum ovulation occurring approximately 27 days after the application of the nutritional treatments (1.76 ± 0.60 versus 1.25 ± 0.45); 9 of the 13 goats ovulating in the PEG treatment were bearing more than one corpus lutuem in comparison to only 3 out of 12 females in the C group (P < 0.05). The likely increased availability of proteins in the PEG receiving goats could explain their higher ovulation rate.     

Effects on animal performance and sward composition of mixed and sequential grazing of permanent pasture by cattle and sheep

Previous experiments have shown that mixed or conjoint grazing, when two or more animal species are grazed together, can lead to improved performance of one or more of the species and a higher total output per unit area. Sequential grazing systems, when different animal species graze an area in succession, also have the potential to improve productivity. This experiment directly compared these two approaches for integrating the grazing of cattle and sheep when pastured on improved permanent pasture. Four treatments were compared: 1) sheep only from May to October (S/S); 2) cattle only from May to July followed by sheep only from August to October (C/S); 3) cattle and sheep from May to July, sheep only for the rest of the growing season (C + S/S); and 4) cattle and sheep from May to October (C + S/C + S). Each treatment was replicated three times. From May until weaning at the end of July the plots were grazed by steers and ewes and lambs, and from weaning until October by steers and lambs. Sward heights were maintained at 6 cm using a “put and take” stocking system. Animal performance and sward composition data were collected during three growing seasons, 2001–2003. During the pre-weaning period lambs grazing plots which were grazed only by sheep had significantly poorer growth rates than those grazing plots where there was mixed grazing. Lambs grazing the sheep only plots also had lower liveweight gain during the post-weaning period, with the highest growth rates being recorded on the C + S/C + S treatment. Carrying capacity and total liveweight gain per unit area post-weaning were also consistently higher for the C + S/C + S treatment, while carrying capacity pre-weaning was highest for the C/S treatment. Measurements of clover content in the grazed horizon and botanical separation of material from quadrat cuts indicated that even under relatively controlled conditions choice of grazing system can influence sward composition. However, there was no clear link between any single sward change and the growth of the animals, indicating that the improved performance of cattle and sheep under mixed grazing is the result of a combination of factors, rather than a response to a particular sward parameter.     

Variation in quantity and quality of native forages and grazing behavior of cattle and goats in Tanzania

The study was conducted to assess the effects of seasonal variation in the quality and quantity of pasture and management of livestock exclosures (ngitili) on the grazing behavior of cattle and goats. The study was 2×2×2 factorial design with three independent variables: season (Dry or Rainy), ngitili management (Private or Communal) and animal species (Cattle or Goats). Focal and scan observation methods were used to record different behavioral activities. Vegetation attributes from the study areas were measured in two consecutive seasons. Most key forage species had significant higher crude protein (CP) content and in vitro organic matter digestibility (INVOMD) in rainy than in dry season (P<0.05), but Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF) did not vary significantly with season (P>0.05). ADF and NDF were significantly higher in species from communal ngitili than those from private ngitili (P<0.05). Above-ground herbaceous biomass and bulk density (BD) were significantly higher in the rainy season and in the private ngitili than in the dry season and in the communal ngitili respectively. Cattle and goats spent considerably more time grazing and browsing respectively in the rainy season than in the dry season (P<0.05). Cattle foraging activities did not vary significantly (P>0.05) with ngitili management, but goats found to spend considerably more time browsing in the communal ngitili and more time grazing in the private ngitili (P<0.05). Despite the merits of stocking cattle and goats together in the heterogeneous pasture, seasonal variation in forage resources requires investigation of other strategies such as use of multipurpose trees and treatment of crop residues to improve livestock production.     

Ehrlichia ruminantium seroprevalence in domestic ruminants in Ghana; I. Longitudinal survey in the Greater Accra Region

Serum samples collected monthly over a 34-month period from cattle, sheep and goats in the Greater Accra Region of Ghana were tested for antibodies to Ehrlichia (previously Cowdria) ruminantium, the causative agent of heartwater, by polyclonal competitive ELISA (PC-ELISA). Maternal antibodies, detected in about half of animals followed from under 1 month old, declined to negative levels within 2–4 months. Amblyomma variegatum tick vectors were present on livestock in rural areas throughout the year, and first seroconversion occurred at any age, although the majority of calves seroconverted between 1 and 10 months old, sheep by 11 months, and goats by 7 months. All the cattle in the study became seropositive by 20 months of age, except one animal which subsequently died of heartwater. Following seroconversion, 25% of bovine sera tested negative in the PC-ELISA. Just over half the sheep in the survey seroconverted before or during the study period; following seroconversion, less than 3% of ovine sera became PC-ELISA negative. About a quarter of the goats seroconverted, and 34% of their post-seroconversion sera tested negative in the PC-ELISA. Overall, the serology indicated that virtually all cattle on the survey farms were exposed to E. ruminantium without suffering disease, but that a substantial proportion of sheep and goats escaped exposure and thus formed a susceptible population. E. ruminantium was detected in brains of 14, 36 and 4% of cattle, sheep and goats submitted for post mortem at the Accra Veterinary Laboratory, indicating that sheep were most at risk from heartwater disease.     

Livestock production in central Mali: Environmental and pathological factors affecting morbidity and mortality of ruminants in the agro-pastoral system

Data were collected on environmental and pathological factors affecting the morbidity and mortality of cattle, sheep and goats in a traditional livestock production system in central Mali. Preweaning death rates were 10, 28 and 35% in the three species. Adult mortality was about 5% year⁻¹ in cattle and 12–13% year⁻¹ in sheep and goats. Management system, season and year were environmental variables which had important effects on the mortality rate. Malnutrition was a major cause of morbidity and mortality in all species and mange caused a high incidence of morbidity. Pulmonary diseases were more serious in goats than in sheep and were relatively unimportant in cattle. Liver fluke caused major economic loss in sheep in the irrigated system. Strategies for reducing morbidity and mortality are discussed.     

Cryptosporidium infection in non-human hosts in Malawi

Of 1346 faecal samples from the Chikwawa and Thyolo districts of Malawi, analysed for the presence of Cryptosporidium oocysts between October 2001 and May 2003, 61.3% were from cattle (29.8% of these were from calves <6 months old). Cryptosporidium oocysts were detected during all three seasons studied in Chikwawa and Thyolo. In Chikwawa, 13.6% of adult cattle and 11.7% of calves were infected, compared to 28.9% of adult cattle and 36.7% of calves in Thyolo. Dependent on season, between 7.8% and 37.7% (Chikwawa) and 16.7% and 39.3% (Thyolo) of cattle samples contained oocysts. In Chikwawa, the highest percentage of infections occurred in the cool season, whereas in Thyolo, the highest percentage of infections occurred in the dry season. Faecal samples from goats [n=225], pigs [n=92], sheep [n=6]), rabbits, guinea pigs, chickens, ducks, turkeys, doves and guinea fowls were also analysed. Up to 5.6% of goat samples contained oocysts in Chikwawa, compared to between 16.7% and 39.3% in Thyolo. Again, in Chikwawa, the highest percentage of infections occurred in the cool season and the lowest in the rainy season, whereas, in Thyolo, the highest percentage of infections occurred in the dry season and the lowest in the cool season. In pigs, more infections were detected in the dry season in Chikwawa, but infections in the cool season were similar (17.7%), whereas in Thyolo, infections occurred in all three seasons (17.9% in the rainy season, 25% in the cool season and 60% in the dry season). Of ten diarrhoeic, oocyst positive cattle faecal samples collected from Chikwawa and subjected to PCR-RFLP, four oocyst positive samples (two from heifers, one from a cow and one unknown) were amplified at an 18S rRNA and Cryptosporidium oocyst wall protein (COWP) loci. RFLP of the 18S rRNA locus indicated that Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium bovis and/or Cryptosporidium ryanae DNA, or a mixture of them was present. Cryptosporidium parvum DNA was identified in one sample that amplified at the COWP locus, indicating the presence of the major zoonotic Cryptosporidium species in Malawi.     

The influence of various types and frequencies of rest on the production and condition of sourveld grazed by sheep or cattle. 2. Vigour

Treatments involving a full growing season rest in alternate years, half a growing season rest (late season) in alternate years and no rest were applied to veld grazed by sheep or cattle at similar stocking rates. Residual effects of the treatments on veld vigour were determined by measuring species regrowth during the season following treatment application, compared to ungrazed controls. The vigour of veld grazed by sheep declined rapidly relative to veld grazed by cattle. The vigour of palatable species was severely impacted, vigour of intermediate species was variably impacted and vigour of unpalatable species increased dramatically on veld grazed by sheep. Similar trends occurred in veld grazed by cattle, but to a lesser degree. Resting was beneficial for vigour recovery in both sheep and cattle treatments but it seems that the grazing treatment between rests has an over-riding influence on veld vigour. The veld grazed by sheep remained at a lower productivity level than veld grazed by cattle. Principles related to resting and the impacts of sheep and cattle grazing are briefly discussed with a view to formulating management strategies.     

放牧强度对山羊采食行为的影响

南方地区水热条件好,草地资源丰富且放牧家畜种类和数量较多,为充分利用当地草地资源,促进草畜平衡,本试验研究了我国西南地区人工草地不同牧压下山羊放牧行为的变化。试验采用野外群体观察法对2种牧压(重牧H和轻牧L)下山羊放牧行为及其参数进行观测记录。结果表明,2种牧压下放牧山羊采食时间都极显著(P<0.01)大于其他行为时间;鸭茅、黑麦草、白三叶的采食时间分别占总采食时间的29.2%,29.0%,25.4%,3种牧草的采食时间之和极显著(P<0.01)大于杂草的采食时间,但3种牧草之间无显著差异(P>0.05);随牧压增加与时间推移,山羊采食速度逐渐降低,但差异不显著(P>0.05);山羊采食速度与口食量呈现负相关的关系。本研究表明,放牧载畜量作为草地管理手段之一,可用来调控草地组成,增加家畜有效采食量,提高山羊放牧系统的经济效益与当地农民收入。     

Dynamics of digestion in cattle, sheep, goats and deer

Four experiments were conducted to study factors affecting digestibility of forages in cattle, sheep, goats and white-tailed deer. In a series of digestion trials (Exp. 1), the dry matter digestibility of a moderately high fiber diet was greater in cattle than in deer. Digestibilities of the diet in sheep and goats were intermediate and not different from either extreme. In a second series of trials (Exp. 2), relative organic matter digestibilities were for goats more than sheep more than deer. However, in Exp. 2, intake in goats was very low and digestibility appeared to be positively related to retention time and inversely related to turnover rate. Results of three trials (Exp. 3) suggested that rate of digestion was related more to diet than to the animal species consuming the diet. In grazing animals (Exp. 4), goats digested a smaller percentage of consumed material than either cows or sheep during three of four seasons even though diets were of similar in vitro digestibility. This difference was related to a faster turnover and shorter retention time in goats. These data support the concept that there are species differences in gastrointestinal dynamics which may be which may be important determinants of adaptability to grazing conditions.     

Browsing of Grewia occidentalis by domestic stock in a South African savanna: the influence of bush clumps

In South African karoo categorised by multi-species bush clumps, skirted shrub species appear to physically defend the palatable shrub Grewia occidentalis against browsing by eland (Taurotragus oryx). Skirted shrubs appear to defend G. occidentalis by preventing access to plants and by reducing the accessibility of G. occidentalis foliage to the large muzzle of eland. Compared to eland, domestic stock such as goats, have a smaller body and muzzle, and these features may allow them to overcome the physical defence offered by skirted shrubs against the browsing of G. occidentalis. Our study of G. occidentalis browsed by domestic stock indicated that mature and seedling G. occidentalis typically occurred with skirted shrub species. Mature and seedling G. occidentalis growing with skirted shrubs had lower intensities of browsing than other G. occidentalis, and mature G. occidentalis growing with skirted shrubs had greater numbers of fruit than other G. occidentalis. In our study area, a non-selective grazing/browsing system is used and camps are grazed/browsed until a high proportion of forage is removed from most plants. Under this system, mature and seedling G. occidentalis are common within the study area and skirted shrubs appear to provide adequate defence for G. occidentalis against browsing by domestic stock.     

Feeding ecology of four livestock species under different management in a semi-arid pastoral system in South Africa

The Leliefontein communal area in Namaqualand is grazed by mixed species herds that have multiple benefits for pastoralists. This study assessed how the management (herding and free-ranging) of different livestock herds affects their feeding ecology during the wet and dry seasons in a semi-arid shrubland. By using direct observations of livestock grazing in the field, we established their habitat preferences, diet selection and resources overlap. Results indicate that all free-ranging livestock can be considered grazers with cattle being selective. When sheep are herded, they tend to be more generalist feeders and herded goats are browsers. Livestock diet selection and forage preferences are largely linked to the habitats in which they graze and browse. Dietary overlap is highest between free-ranging livestock irrespective of season, whereas herded livestock are able to consume a food source with little potential competition from other livestock. Although the wet-season annual forage resources are able to sustain the livestock population in Leliefontein, this study concludes that the overdependence on annual vegetation would make livestock vulnerable during drought periods when forage production is low.     

The Effect of Supplementation with Fresh Browse of Ziziphus mauritiana or Combretum aculeatum on Feed Intake,Nitrogen Utilization and Growth of Grazing Range Sheep

The influence of 0, 60 or 120 min access to a grove of either Ziziphus mauritiana (Ziziphus) or Combretum aculeatum (Combretum) on forage intake and on the digestibility, growth and excretion of nutrients was determined using 40 Oudah rams grazing for 7 h/day on poor-quality dry season pasture in the Sahel. The effects of browse species and browsing duration (0, 30, 60 or 120 min) on the ruminal ammonia content were also evaluated using 8 mature fistulated rams. Ziziphus increased both total digestible organic matter and total dry matter intakes per (kg live weight)^0.75 without decreasing herbage intake, whereas 60 or 120 min access to Combretum reduced herbage intake by 6.3% and 4.2%, respectively. The digestibility of the diet decreased (p<0.05) with the duration of access to the groves. Despite the provision of more nitrogen (N) than in the control diet, ruminal NH₃-N decreased 24 h after browsing commenced. The reduced live weight gain of sheep browsing Combretum may indicate more deleterious compounds in Combretum than in Ziziphus. Ziziphus appears to have more potential than Combretum to increase sheep production in low-input crop/livestock systems.     

内蒙古典型草原三种家畜采食量和食性选择的研究

放牧家畜的采食量和对不同牧草的选食性是制定草地放牧管理的基本参数。本研究选取内蒙古典型草原,在相同放牧强度下比较绵羊、山羊和牛的采食量及牧草选择性。结果表明：在相同放牧强度下,夏秋季节放牧牛的平均日采食量为9.64 kg·（头·天）^-1,喜食大针茅、黄囊苔草和一些非优势种牧草（选食系数1 < SI≤1.5）,而对羊草和糙隐子草表现为可食（0.5 < SI≤1）;绵羊的平均日采食量为1.87 kg·（头·天）^-1,喜食羊草、黄囊苔草和其它非优势种牧草（1 < SI≤1.5）,而对大针茅和糙隐子草表现为可食（0.5 < SI≤1）;山羊的日均采食量为1.65 kg·（头·天）^-1,嗜食其它非优势种牧草（SI>1.5）,喜食黄囊苔草和糙隐子草（1 < SI≤1.5）,而对羊草和大针茅表现为可食（0.5 < SI≤1）。本研究意味着不同家畜或多种家畜混牧可更高效的利用草地资源,如放牧绵羊和牛可能分别减少羊草和针茅在草地中的丰度,因而采用不同家畜放牧或多种家畜混牧有利于草地的可持续利用。     

The coccidia of sheep and goats in Senegal

A survey of the coccidia in domestic sheep and goats was undertaken to ascertain the type of Eimeria species and the number of different coccidial species in individual faecal samples. Simultaneously the prevalence and the oocyst output was investigated in 2234 sheep and 577 goats during a 12-month period. Eight Eimeria species were encountered in sheep: E. ahsata, E. crandallis, E. faurei, E. intricata, E. ovina, E. ovinoidalis, E. pallida and E. parva.

In goats the following species were found: E. ahsata, E. arloingi, E. christenseni, E. crandallis, E. faurei, E. intricata, E. ninakohlyakimovae and E. parva.

The prevalence in sheep was 94% and in goats 85%, multiple parasitism was the rule. No seasonal fluctuation was observed in the prevalence or oocyst output. The sheep and goats' oocyst output was moderate, the mean for both being in the range of 1000–5000 oocysts/g of faeces.     

The ecological potential of the kudu for commercial production in savanna regions

Abstract

This paper considers the choice of a browsing ungulate to supplement cattle in savanna regions susceptible to problems of bush encroachment, and evaluates the kudu in particular. Relevant aspects of its ecology considered include (i) the vegetation components utilized at different seasons and in different areas, with regard to principal food species, reserve dry season species, rejected plant species and potential food limitations; (ii) social grouping patterns and home range extent; (iii) population densities, reproductive parameters, survival rates and population dynamics in relation to rainfall; (iv) impact on the vegetation of browsing and branch breakage. Features of the kudu are compared with those of other browsing ungulates, including giraffe, eland, impala and goats. It is concluded that the kudu is a prime candidate for inclusion alongside cattle in mixed species ranching enterprises in most regions of savanna vegetation.     

Research note: Tests for inducible thorn defences against herbivory must consider plant growth strategies

Abstract

Thorn length and density on the latest year's growth were compared at three height (feeding) levels (<1m, >1m<2 m and >2 m) on individuals of Acacia karroo and Ziziphus mucronata in an area that was browsed by goats. Thorn length and density was greatest for branches within easiest reach of goats. However, there was no increase in thorn length or density on the latest year's growth of branches of A. karroo individuals protected from browsing. Thorns on distal ends of branches are relatively small and sparse and this is partly due to differences in internode length. Herbivores limit the extent of annual growth and this prevents development of small thorns characteristic of late season growth. Thus, browsed individuals which lack late season growth may have greater spinescence. This is only a passively induced response and is not due to the active production of larger thorns subsequent to browsing.     

Differences in choice of diet between sheep breeds grazing mountain pastures in Norway

In the present study, the foraging behaviour of ewes from three common Norwegian sheep breeds; the long-tailed Dala sheep, and the two short-tailed breeds Spæl sheep and Norwegian Fur sheep was studied. Based on difference in body size and digestive anatomy, we expected the lighter short-tailed ewes to browse more on woody plants than the Dala ewes. The experiments were conducted during two consecutive summers within the flocks’ usual grazing areas, and we sampled the proportion of grazing time that ewes spent feeding on woody plant species. We tested the hypothesis by applying generalized linear mixed models to the feeding behaviour data. As predicted, the short-tailed ewes spent substantially more of their grazing time browsing on trees, bushes and heather compared to the Dala ewes. We discuss the results in the context of maintaining the, now threatened, pastoral landscapes of mountainous regions of Norway; short-tailed breeds should be more effective than the Dala breed in reducing tree and bush encroachment, but more detailed studies are needed to quantify the breed differences in this respect.