Rotational Stocking System Research Articles

Eco‐efficiency of leys—The trigger for sustainable integrated crop‐dairy farming systems

AbstractThe specialisation of agricultural systems in Western Europe and the intensification of livestock and cropping production are intrinsically linked to substantial resource inputs. This intensified approach frequently leads to nutrient surpluses and biodiversity loss, resulting in detrimental environmental impacts. A transformative agricultural shift is imperative in light of climate and environmental protection objectives. Addressing this need, the Lindhof eco‐efficient pasture‐based milk production initiative, initiated in 2016, is a tangible manifestation of a productive and profitable dairy system integrated within a ley‐based Integrated Crop‐Livestock System (ICLS). Operational at the organically managed Lindhof farm, this approach involves a rotational stocking system of spring‐calving Jersey cows stocked on grass‐clover‐herb leys embedded within a cash crop rotation. The dairy cows benefit from these highly productive swards, rich in nutritive value comparable to concentrate feeding. At the same time, the cultivated crops derive advantages from the legacy effect of leys due to nutrient exchange facilitated by grazing excreta and residual crop matter. Compared to specialised systems, the ley‐based ICLS emerges as an alternative dairy production paradigm that supports many ecosystem services – including minimised nutrient losses, a lower carbon footprint and positive contributions to agro‐biodiversity. These outcomes are realised without compromising overall land‐use efficiency while reducing environmental and social costs of 20–30 Eurocent per kg of milk produced compared to specialised systems. Thus, the ley‐based ICLS conforms to the principles of ecological intensification, enhancing functional diversity within the agricultural landscape. Essentially, the Lindhof initiative represents a holistic and environmentally responsible approach to farming that could contribute to realising the EU Farm to Fork Strategy.

Determining the pre-grazing sward height of Kikuyu grass (Cenchrus clandestinus - Hochst. ex Chiov.) for optimizing nutrient intake rate of dairy heifers.

Understanding the grazing process and animal response to sward structures (e.g., sward height) is key to setting targets for efficient grazing management. We hypothesized that the short-term intake rate (STIR) of dry matter (DM) and digestible organic matter (OM) by dairy heifers is maximized with Kikuyu grass (Cenchrus clandestinus—Hochst. ex Chiov.) of intermediate sward heights. The treatments consisted of five pre-grazing sward heights (10, 15, 20, 25, and 30 cm) randomly assigned to two of ten paddocks. The experimental design included two measurements of each paddock at different periods and times of day. Three Holstein heifers (440 ± 42 kg body weight) were used to determine the STIR, which was estimated using the double-weighing technique with correction for insensible weight losses. The bite mass (BM), bite rate (BR), sward structural characteristics, and nutritional value of herbage samples were assessed. The data were analyzed using mixed models with a factorial arrangement of five sward heights, two times of day, and two evaluation periods. The sward height of Kikuyu grass that maximized both STIRs was approximately 20 cm. The STIR of the DM was 30% and 15% lower than the maximum in the shortest and tallest swards tested, respectively. In swards shorter than 20 cm, the STIR was lower because the BM decreased with sward height, whereas in those greater than 20 cm, the lower BM and STIR of DM was explained by a decrease in bulk density and bite volume. The top stratum was composed mainly of highly digestible leaf blades with similar nutrient content across sward heights; therefore the STIR of digestible OM was also maximized at 20 cm. Hence, the optimal pre-grazing sward height of Kikuyu grass should be managed at 20 cm under rotational stocking systems to maximize nutrient intake rate of dairy heifers.

Effect of mineral-energy supplementation on the performance of young bulls from different genetic groups on pasture

The aim of this study was to evaluate the performance of young bulls from three genetic groups, ½ Brangus x ½ Nellore (BRN), Nellore (NEL) and ½ Canchim x ½ Nellore (CAN), reared on pasture and supplemented with mineral (MS) or energy-mineral (MES) supplement. Eighty-one bulls, with a mean age of 12 months and mean body weight of 252 ± 33 kg were used. The experiment was conducted in a 3x2 factorial completely randomized design. Each genetic group was subdivided into six experimental plots, three received MS and three received MES. Animals were managed in a rotational stocking system in a Tifton 85 grass pasture. The consumption of MS was similar between the genetic groups with an average of 0.073 kg animal-1 day-1, whereas the consumption of MES was higher for BRN, 2.10 kg animal-1 day-1, followed by CAN, with 1.57 kg animal-1 day-1, and lower for NEL, with 1.28 kg animal-1 day-1. The average daily weight gain (ADG) was greater for animals that received MES compared to those that were given MS. For animals that received MS, the BRN group had ADG of 0.64 kg animal-1, while the NEL and CAN groups were similar with a mean of 0.46 kg animal-1. For animals that received MES, the CAN group had higher ADG, 0.97 kg animal-1, while the NEL and BRN groups were similar, with an average of 0.86 kg animal-1. Blood levels of total protein, albumin, creatinine, glucose and cholesterol did not change depending on the types of supplements used or between genetic groups. Higher serum urea levels were observed in NEL and CAN animals that received MS. Serum aspartate aminotransferase levels were higher in BRN and CAN animals that received MES. Gains in rump height, height at the withers, body length, rump width and chest perimeter were greater in animals that received MES. Mostly, the gains in morphometric measurements were greater for crossbred animals than for the NEL group. The supply of mineral-energy supplement in Tifton 85 grass pasture during the rainy season is recommended only for Nellore and ½ Canchim x ½ Nellore young bulls. Crossbred young bulls show greater gains in morphometric measurements than Nellore young bulls during rearing.

Effect of pre-grazing herbage mass on pasture production and performance of suckler-bred steers during the grazing season and subsequent indoor finishing period

The objective was to determine the effect of pre-grazing herbage mass (PGHM) on herbage production and nutritive value, intake and growth of suckler-bred steers in a rotational stocking system, and the residual effects on intake, growth and carcass traits during subsequent indoor finishing. A total of 108 yearling steers previously offered grass silage indoors over 105 days were assigned to one of two PGHM (1500 – low (L) or 2000 – high (H) kg dry matter (DM)/ha; > 4 cm) treatments. Steers (ca. 345 kg at turnout to pasture in spring) rotationally grazed perennial ryegrass (Lolium perenne) dominant pasture in 12 groups of 9 for 203 days. At the end of the grazing season they were housed indoors and offered either (1) grass silage only or (2) grass silage + 3.17 kg concentrate DM/head daily for 136 days until slaughter at 24 months of age. Annual herbage production was higher (8427 vs. 7542 kg DM/ha, P < 0.01) for H than L, but there was no difference between treatments in surplus herbage removed as silage due to the tendency for H steers to consume more herbage/ha while grazing (7363 vs. 6479 kg DM/ha, P = 0.08). During the grazing season, compared to L, steers grazing H had a greater estimated herbage DM intake (6.59 vs. 5.93 kg DM/ha, P < 0.001), daily live weight gain (0.81 vs. 0.76 kg, P < 0.01), live weight at the end of the grazing season (553 vs. 539 kg, P < 0.01) and live weight gain/ha (1261 vs. 1206 kg/ha). During the indoor finishing period there was no PGHM × finishing diet interaction, and no residual effect of PGHM on daily live weight gain, but carcass weight tended to be heavier for H (359 vs. 354 kg, P = 0.06) than L. Compared to silage only, the silage + concentrates group had a higher (P < 0.001) total DM and energy intake, feed conversion efficiency, live weight gain, carcass weight and carcass conformation and fat score. In conclusion, grazing the lower PGHM reduced herbage production, steer live weight gain at pasture, overall live weight gain/ha and tended to reduce carcass weight; therefore, under the conditions of this experiment grazing a PGHM of 2000 kg DM/ha is recommended. Removing concentrates from the finishing diet reduced carcass weight and fatness, making it more difficult to finish steers at a commercially acceptable carcass (carcass fat score > 6.0, 1 - 15 scale).

How canopy structural and morphological characteristics, and forage chemical composition affect a pasture-based dairy system?

Pasture-based systems are prevalent among small-scale family farms. Many farmers consider that the nutritional value of the plant is more relevant than the canopy structure. This study aimed to analyze the various factors related to plant structure and chemical composition that most influence milk yield per hectare under rotational stocking. The experiment was performed at the Animal Husbandry Experimental Station of the Extreme South of Bahia. Three rotational stocking systems with three forage species [Cynodon dactylon (L.) Pers. cv. Tifton 85, Urochloa brizantha (Hochst. ex A. Rich.) Stapf. cv. Xaraés, and Megathyrsus maximus Jacq. cv. Mombasa] were evaluated. Nine crossbred Holstein x Gyr cows were allocated to a balanced 3 x 3 Latin square design. The cows were rotated in three pastures every 14 days. The experimental period consisted of seven evaluation cycles of 42 days each. Cluster analysis, principal component analysis (PCA), and multivariate linear regression were the statistical techniques used to evaluate plant structure and morphological characteristics, and animal performance. Xaraés palisadegrass and Mombasa guinea grass were similar for all evaluated characteristics (P &gt; 0.05), whereas Tifton 85 was different from them in terms of structural, morphological, and chemical composition characteristics (P &lt; 0.05). In the PCA, 59.1% of the total variance was explained by components 1 and 2 for the structural and morphological characteristics, and forage chemical composition. Forage structural and morphological variables showed better results in the multivariate linear regression analysis for milk yield per hectare. Structural and morphological characteristics were more correlated with Mombasa guinea grass than Xaraés palisadegrass and Tifton 85. The structural and morphological characteristics of forages were the main factors determining milk yield per hectare in exclusively pasture-based systems with animals of low production.

Physiological and behavioural responses of sheep grazing in a tropical silvopastoral system

Context Integrating trees and pastures can provide benefits to grazing animals in warm climates, such as provision of shade during the excessive heat. Aim Our aim was to evaluate the effects of two arrangements of trees on grass production and behavioural, physiological and blood parameters of crossbred lambs grazing massai grass (Megathyrsus maximus) pastures in a tropical environment in São Paulo state, Brazil. Methods Two groups of 24 Santa Inês × Dorper male lambs (~90 days old, 24.0 ± 3.3 and 22.0 ± 2.4 kg bodyweight, respectively) were used in two growing seasons, stratified by initial bodyweight and randomly assigned to one of three treatments: unshaded massai grass (no shading, NS), moderate shading (MS), or intense shading (IS). Treatments MS and IS were established with single rows of eucalyptus trees at spacing 12 m or 6 m between rows and 2 m within rows, corresponding to 786 and 1190 trees/ha. Each growing season consisted of two grazing cycles of ~20 days each, when tester animals grazed simultaneously in a rotational stocking system with variable stocking rate. Behavioural observations were feeding, lying ruminating, standing ruminating, lying, standing still, searching for food, and other. Physiological measurements were rectal temperature, respiratory frequency and heart rate. Blood parameters included haemogram, acute-phase proteins and serum cortisol concentrations. Key results Animals under treatment IS spent more time (P &lt; 0.05) lying, standing still and at other activities than animals under NS and MS. Moreover, they presented lower rectal temperature and respiratory and heart rates than animals under NS during the first growing season, which was the season with higher temperatures. Cortisol and acute-phase proteins were not affected by treatment. Conclusions When animals were exposed to sun, the silvopastoral system was efficient for avoiding heat stress; however, the density of trees reduced the forage mass. Implications The silvopastoral system is a viable alternative production system in warm climates to improve the welfare of sheep, but the density of trees must be considered so that it does not negatively influence the forage mass.

Temperament of Nelore growing-steers receiving supplementation in grazing system: Performance, ultrasound measures, feeding behavior, and serum parameters

A study was performed to evaluate the temperament of beef cattle on grazing system regarding performance, ultrasound measures, feeding behavior, and physiological parameters. Twenty growing animals [Nelore; non-castrated males; 220 ± 33 kg initial body weight (BW); 10 ± 1 months of age] on rotational stocking system (Urochloa brizantha cv. Xaraés) were used. Individual temperament scores were calculated by averaging animal chute score and exit velocity score [adequate (ADQ) ≤ 3; or excitable (EXC) > 3] at the beginning of the trial period (d 0). At the same day, animals were ranked by temperament and BW, and assigned to receive (n = 10) or not (control = CON; n = 10) a supplementation (SUP). Body condition score (BCS), BW, hip height (HH), and ultrasound evaluations (ribeye area - uLMA; backfat thickness - uBFT) were recorded on d 0 and 84. Difference between BW (d 84 and 0) were used to determine the average daily gain (ADG). Blood samples were collected at 0, 28, 56, and 84 d and analyzed for serum cortisol, insulin, and haptoglobin. Feeding behavior data (time of grazing, rumination, resting, and drinking water) were obtained by all-animals scan sampling (4 d; 24-h per day). No interactions of temperament with supplementation were detected for performance. ADQ animals had a greater initial and final BW (P ≤ 0.032), and ADG (P = 0.031) than EXC animals. No differences were found for the other growth performance variables studied regarding temperament classification. SUP group had greater values for final BW (P< 0.001), ADG (P< 0.001), initial and final uLMA (P ≤ 0.002), and higher final HH (P = 0.007) than CON group. Interactions of temperament with period (P< 0.01) were observed for grazing, rumination, and resting behaviors. ADQ animals showed higher probability of grazing, ruminating, and resting events during some periods of the day, whereas EXC animals had higher probability of ruminating events and resting events in other periods. No effects of temperament were identified for serum parameters (P ≥ 0.157), however, a tendency for diet effect was detected (P = 0.066) for cortisol concentration, for which SUP animals showed higher values than CON animals. In conclusion, growth performance and feeding behavior are impacted in Nelore growing cattle by temperament and supplementation. Therefore, animal temperament is a characteristic that must be considered in beef cattle produced in grazing systems.

Tall fescue sward structure affects the grazing process of sheep

The study of factors influencing animal intake can provide a better understanding of the dynamics of the pasture ecosystem and serve as a basis for managing livestock in a more efficient way. We measured different sward surface heights of tall fescue in the process of short-term intake rate of sheep. There was a significant effect of sward surface height on herbage mass (P < 0.001), leaf lamina mass (P < 0.001), other species mass (P = 0.02), bite mass (P = 0.01) and short-term intake rate (P = 0.03) of sheep. There was a quadratic fit between time per bite and bite mass (P = 0.006). Multivariate analysis showed that the short-term intake rate and bite mass were positively correlated (r = 0.97), bite rate and total jaw movement rate were positively correlated but both were negatively correlated with time per bite. The sward surface height of tall fescue corresponding to the maximum short-term herbage intake rate was 22.3 cm. The underlying processes were driven by the bite mass, which was influenced by the leaf lamina bulk density and its consequences upon time per bite. This sward surface height can be adopted as a pre-grazing target for rotational stocking systems to optimize sheep nutrition on pastures.

The effect of grazing intensity on the performance of high‐yielding dairy cows

AbstractThe study evaluated the impact of High, Moderate and Low grazing intensities throughout the grazing season, within a rotational stocking system, on the performance of high‐yielding dairy cows receiving a high level of concentrates. Sixty‐three Holstein‐Friesian dairy cows, 21 at each grazing intensity, were rotationally grazed. Average paddock size, post‐grazing sward heights and seasonal grazing stocking rates within the High, Moderate and Low grazing intensities were 0.143, 0.167 and 0.200 hectares, 5.2, 6.1 and 6.8 cm and 7.8, 6.7 and 5.6 cows ha−1 respectively. Grazing intensity had no effect on milk fat and protein content, end‐of‐study body condition score or end‐of‐study live weight although the latter tended towards significance (p = .057). Average daily milk yield per cow was higher within the Low grazing intensity (33.2 kg day−1) than High grazing intensity (30.5 kg day−1), and average daily fat‐plus‐protein yield was higher for Low and Moderate than High. Milk output per hectare was higher for the High grazing intensity than Low grazing intensity (33,544 and 26,215 kg ha−1 respectively). Grazing intensity had no effect on grazing bite number, blood metabolites or concentrations of milk fatty acids or on sward morphological components, although dead matter increased with time across all grazing intensities. Herbage utilization efficiency (above 1,600 kg DM ha−1) was 52%, 74% and 87% for Low, Moderate and High respectively. It is concluded that high‐producing dairy cows can graze at high levels of utilization when they are receiving high rates of concentrates. Although cow performance will be reduced, milk yield per ha will increase.

Using plant wax markers to estimate the diet composition of grazing Holstein dairy cows

The objective of this study was to test whether diet selection of dairy cows under grazing conditions could be estimated using plant wax markers. Furthermore, differences between 2 cow strains and the effect of concentrate supplementation on plant species selection were investigated. The experiment was a study with a crossover design performed on an organic farm with 12 Swiss Holstein cows and 12 New Zealand Holstein cows. Both experimental periods consisted of a 21-d adaptation and a 7-d measurement period. All cows grazed full time in a rotational stocking system and received either no concentrate or 6 kg/d of a commercial cereal-grain mix. Representative herbage samples of each grazed paddock were taken and botanical composition of subsamples was manually determined. The average proportions of the plant species were 27.8% Lolium perenne, 6.1% Dactylis glomerata, 10.4% Trifolium repens, and 9.0% Taraxacum officinale. Other grass species were merged as "other grass" (38.2%) and other forb species as "other forbs" (8.5%). n-Alkanes, long-chain fatty acids, and long-chain alcohols (LCOH) were analyzed in the samples of plant species, concentrate, and feces from each cow. A linear discriminant analysis indicated that diet components were differentiated best with LCOH (96%) and worst with the combination of all marker groups together (12%). For each marker, the fecal marker recovery (FR) relative to dosed ytterbium was determined in 2 ways. Estimation of diet composition was performed with the software "EatWhat," and results were compared with botanical composition with the Aitchison distance. The results indicate that the diet composition of grazing dairy cows can be estimated using plant wax markers. Additionally, the calculation of FR led to mostly reliable results, yet this approach needs further validation. The most accurate estimation was achieved with the marker combination of n-alkanes and LCOH with a correction for FR. Less accurate estimations were achieved with long-chain fatty acids alone or in combination with n-alkanes. No difference relating to diet selection between the 2 cow strains was recorded, but supplemented cows apparently ingested higher proportions of T. repens than nonsupplemented cows. Awareness that supplementation influences selection behavior of grazing dairy cows may lead to adaptations in botanical composition of the pasture according to the demand of the animals.

Efeito de diferentes sistemas de pastejo em atributos físicos do solo

In view of the importance of the interaction soil-climate-plant-animal to attain good yields in the system, the objective of this study is to evaluate changes in soil physical properties caused by grazing systems continuous and rotated. The systems were used: conventional (CC): Brachiaria brizantha cv. BRS Piatã, unfertilized annual replacement, managed under continuous stocking; fertilizer (AD): Brachiaria brizantha cv. BRS Piatã managed under rotational stocking system, with annual replacement fertilization with NPK at a ratio of 45-20-20 kg ha-1 year-1, and intercropping (IC): Consortium of Brachiaria brizantha cv. BRS Piatã and Stylosanthes Campo Grande, managed in a rotational system of stocking, fertilization receiving annual replacement with 00-20-20 NPK kg ha-1 year-1. To evaluate the effect of animal trampling on systems with rings were collected soil samples with undisturbed layers from 0.00 - 0.06 m, 0.06 - 0.12 m before and after grazing for the determination of soil density by the volumetric ring method, macroporosity and total porosity by the method of the tension table, were also collected samples deformed structure in the same layer for determining the organic matter content. The resistance to penetration was determined before and after grazing in the depths of 0.0 - 0.1, 0.1 - 0.2, 0.2 - 0.3 and 0.3 - 0.4 m, with the impact penetrometer. Animal stepping changed only the microporosity, the use of different cropping systems and grazing no differences in relation to organic matter content. The soils of the conventional grazing system were more tendency to soil compaction measured by penetration resistance of roots.

Impact of the post-weaning parasitism history on an experimental Haemonchus contortus infection in Creole goat kids

Gastrointestinal nematode (GIN) infections have an important negative impact on small ruminant production. The selection of genotypes resistant to these parasitic infections is a promising alternative control strategy. Thus, resistance against GIN is an important component of small ruminant breeding schemes, based on phenotypic measurements of resistance in immune mature infected animals. In this study we evaluated both the impact of the post-weaning parasitism history on the response to an experimental Haemonchus contortus infection of resistant and susceptible Creole kids chosen on the basis of their estimated breeding value, and the interaction with the kid's genetic status. During the post-weaning period (from 3 months until 7 months of age) Creole kids were reared at pasture according to four different levels of a mixed rotational stocking system with Creole cattle: 100% (control), 75% (GG75), 50% (GG50), and 25% (GG25) of the total stocking rate of the pasture. The level of infection of the kids decreased significantly at 50% and 25% of the total stocking rate. After the post-weaning period at pasture, at 11 months of age kids were experimentally infected with H. contortus. The faecal egg counts (FEC) were significantly lower in the groups showing the highest FEC at pasture. This result suggests that a degree of protection against an experimental H. contortus infection occurred during the post-weaning period and was dependant on the level of parasitism. Interestingly, no interaction was observed between this level of protection and the genetic status. In conclusion, the level of post-weaning natural parasitism history at pasture would not influence the genetic status evaluation. More generally our results suggest that it would be better to expose kids to a high level of gastrointestinal parasitism during the post-weaning period in order to increase the basal level of resistance thereafter.

Rotational stocking management affects the structural and nutritional characteristics of Guinea grass swards and milk productivity by crossbred dairy cows

The type of stocking system can affect sward canopy structure, changing the nutritional value of herbage and livestock production. The present study evaluated structural and nutritive features of Guinea grass (Panicum maximum Jacq. var. Tanzânia) swards and the composition and yield of milk produced by crossbred cows fed this herbage in a rotational stocking system over cycles from Spring to Autumn. Two stocking systems were tested, in which cattle were allowed to graze: (1) after grazing cycles of 30 days (T30d); or (2) when the sward reached a pre-grazing height of 70cm (T0.7m). Five grazing cycles, each consisting of a sward recovery period followed by 2 days of grazing, were evaluated in each stocking system using a completely randomized block design and repeated measures with 2 repetitions per stocking system (each composed of a set of sixteen 4000m2 paddocks grazed sequentially). Four 1m×1m sward patches were collected, constituting one sample per paddock, which was used to evaluate pre-grazing herbage mass, leaf, stem and dead matter (dry mass per area), crude protein (CP), neutral detergent fiber (NDFom), acid detergent fiber (ADFom) and hemicellulose (HEM). Cows received daily supplementation of 4kg concentrate. Stocking rate, milk production and composition were evaluated in each grazing cycle. The T30d stocking system produced higher (P=0.0014) pre-grazing height than T0.7m (0.83 vs 0.69cm), had higher (P=0.0071) light interception (94 vs 91%) and higher (P=0.0233) leaf area index (5.2 vs 4.5). In addition, T30d exhibited larger (P=0.0204) herbage mass than T0.7m (7276 vs 6187kg MS/ha), higher (P= 0.0243) leaf dry mass per area (2618 vs 2294kg/ha) and higher (P<0.0001) stocking rate (6.2 vs 5.7animal/ha). The grazing cycle affected sward composition, with T30d producing higher (P=0.0060) leaf NDFom. Milk production and composition was not affected by the stocking systems, as follows (T30dvs T0.7m): 20.12 vs 20.94kg milk production per cow/day; 31.4 vs 31.9gfat/kg, 29.9 vs 30.2gprotein/kg, 43.7 vs 44.6glactose/kg, 114.8 vs 116.5g/kg total solids and 12.85 vs 12.86mg/dL ureic nitrogen. Stocking system therefore affects the nutritive value of sward. Stocking management allowing a 30-day grazing cycle for Guinea grass sward (T30d) produces higher forage mass, supporting a higher stocking rate and thereby increasing productivity in dairy farm.

Effects of stocking rates on gastrointestinal nematode infection levels in a goat/cattle rotational stocking system

Gastrointestinal nematodes (GIN) are increasingly resistant to anthelmintic drugs worldwide, so integrated control methods are more and more needed for the sustainability of small ruminant farming. Such methods rely on knowledge in epidemiology, physiology, and genetics. Ecological studies have highlighted the effect of host density on parasite populations, and in the humid tropics, rotational grazing systems were designed according to the survival of GIN free-living stages. This study aimed to assess the effects of mixed stocking and host stocking rate on host GIN infection level.Four groups of 15–17 Creole male kids were raised on irrigated pasture from weaning (about 3 months) until the age of 7 months, at four partial stocking rates (pSR): 100% (control), 75% (G75), 50% (G50), and 25% (G25) of the total stocking rate of the pasture. The last three groups were associated with weaned Creole heifers to obtain the same overall stocking rate as the control. Animals grazed in a ‘leader’ goat and ‘follower’ cattle design: the G25, G50, and G75 paddocks were split into six plots; each plot was grazed by goats for 1 week and by heifers the following week. The pasture then rested for 4 weeks before the animals were returned for a new grazing sequence. Five control plots were grazed rotationally for 1 week, and rested for 4 weeks. This design was repeated three times a year for a total of 10 repetitions. Average faecal egg counts (FEC) decreased according to a power function of the pSR: FEC=1829pSR3.7. The observed death rate decreased significantly with the pSR (27.6%, 16.4%, 11.9%, and 12.2%). The kids grew faster in G25 (51gd−1) than in G50 (43gd−1) and G75 or control (32gd−1, p<0.05). Heifers were not significantly infected with GIN and grew normally (about 0.48kgd−1).Reducing the pSR by associating a non-host species in a rotational stocking system may be a very promising component of integrated GIN control, at least for the humid tropics.

Canopy Cover and Herbage Accumulation of Fourteen Grassland Species When Stocked with Chickens

Maintaining intact vegetation in the outdoor run of chickens (Gallus gallus domesticus) can be difficult due to intense stresses such as defoliation and concentrated manure. The aim of this study was to determine the extent to which damage‐tolerant plant species can improve canopy cover. In a 2‐yr field experiment, we subjected 14 disturbance‐tolerant grassland plant species (nine grasses and five forbs) to stocking with laying hens for short (1‐d), medium (2‐d), and long (3‐d) periods in a rotational stocking system. The species differed strongly in resistance (canopy cover and density of tillers and vegetation growing points) and resilience (herbage accumulation) to stocking. Repeated stocking but not duration of stocking had a significant effect on herbage accumulation and canopy cover in most of the species. Canopy cover decreased with repeated stocking in the majority of the tested species. In most forbs, increasing stocking duration significantly decreased the density of vegetation growing points; in most grass species, this factor had no significant effect on tiller density. Our results indicated that grasses are generally more suitable for an outdoor chicken run than forbs. The best performance was recorded for Schedonorus phoenix (Scop.) Holub and Poa supina (Schrad.), with &gt;80% canopy cover, constant tiller density, and herbage accumulation of &gt;4.8 g dry matter m−2 d−1 after repeated 3‐d stocking. We conclude that the use of disturbance‐tolerant grassland species will improve swards in outdoor chicken runs.

Activity time budget patterns of sheep and goats co-grazing on semi-natural species-rich dry grassland

Activity time budget patterns and grazing response to sward and environmental conditions were investigated for paddocks of sheep and goats co-grazing for conservation purposes on a semi-natural species-rich dry grassland community endangered by shrub and tall perennial plant encroachment in a protected nature reserve in South Moravia (Czech Republic). Grazing was conducted by a rotational stocking system for 14 weeks in late grazing season in 2008 with 60 dry ewes and 20 goats. Twelve ewes and four goats were observed; grazing, ruminating, idling and other activities (salt licking, social interactions, walking), along with topographical position in the paddock were recorded at 5-minute intervals within 14 hours of daylight. Sheep and goats did not differ in their principal activity time budgets, such as the average total daylight time spent grazing (sheep: 8.57 h, goats: 8.59 h), ruminating (sheep: 1.42 h, goats: 1.44 h), or idling (sheep: 3.23 h, goats: 3.18 h), the duration of bouts of each activity, or the number of bouts of grazing and ruminating. There was no pattern in activity time budgets indicating dynamics in progressing season, nor was there a response to daily average temperature or to paddock size. Sheep and goats showed similar responses to groundcover of particular plant functional types. The animals showed a positive trend in response of total daylight grazing time to grass available biomass and a negative response of total daylight grazing time to herbaceous biomass for both sheep and goats. The total daylight grazing time was independent of availability of woody plants. Goats devoted more time (1.51 h) to other activities than sheep (1.34 h), especially to social interactions and salt licking. On the other hand, sheep spent proportionally more time walking. Both sheep and goats showed similar patterns in spatial use of paddocks on hill slopes, spending the most time in the middle part and the least time in the lower part of paddocks.&amp;nbsp;

Produção e qualidade de pastagens de Coastcross-1 e milheto utilizadas com vacas leiteiras

O uso de pastagens do gênero Cynodon, em propriedades leiteiras do Rio Grande do Sul, tem crescido, especialmente na última década. O objetivo deste trabalho foi comparar a dinâmica, a produção de matéria seca, a qualidade e a composição botânica de pastagens de Coastcross-1 (Cynodon dactylon x C. nlemfluensis) e milheto (Pennisetum americanum) cv. Comum, sob sistema de pastejo rotacionado, com vacas em lactação da raça Holandês. Avaliaram-se a massa de forragem no pré-pastejo (MFPP), a taxa de acúmulo diário de matéria seca (TAD), a produção total de forragem (PTF) e a composição botânica das pastagens. Para o milheto e a Coastcross-1, foram avaliados os componentes estruturais: lâmina foliar (LF), colmo + bainha (CB), outras espécies (OE) e material morto (MM). Na entrada e saída dos animais da pastagem, foram colhidas amostras por simulação de pastejo para determinação dos teores de proteína bruta (PB) e fibra em detergente neutro (FDN). Não houve diferença significativa (P&gt;0,05) para MFPP, TAD, PTF e PB. O milheto apresentou maior disponibilidade de lâminas foliares (P&lt;0,05), menor teor de FDN (P&lt;0,05) na entrada e saída dos animais da pastagem e maior participação de OE (P&lt;0,05). O período total de pastejo foi maior na pastagem de Coastcross-1.

Sward structure and herbage yield of rotationally stocked pastures of 'Marandu' palisadegrass [Brachiaria brizantha (A.Rich.) Stapf] as affected by herbage allowance

In ruminant-forage systems herbage allowance (HAL) has a major impact on grazing intensity and sward structure, affecting animals, plants, and ultimately, pasture yield. Data on HAL responses of tropical cultivated pastures are scarce and this information may be useful in optimizing pasture utilization. The objective of this study was to describe and contrast sward structure and herbage accumulation responses of 'Marandu' palisadegrass [Brachiaria brizantha (A.Rich.) Stapf] pastures to HAL during two grazing seasons (warm-rainy season of 2003 and 2004). Treatments were four daily HAL levels, 5, 10, 15 and 20 kg herbage mass per 100 kg live weight (%) in a rotational stocking system with 35 days of grazing cycle (28-day rest; 7-d grazing). Post-graze swards were shorter (~17 cm) under 5% HAL. For the other HAL levels, postgraze sward height increased throughout the experiment (21 to 50 cm). Changes in sward light interception (LI) were highly associated with height, but differed across HALs in 2004. Early in the 2003 season, HAL increases resulted in linear increase of the daily herbage accumulation rate (HAR; 47, 66, 78, and 98 kg DM ha-1 d-1 for 5, 10, 15 and 20%-HAL, respectively). For the subsequent grazing cycles of 2003 and all through 2004, HAR decreased with increasing HAL. This was associated with the excessive increase in sward height and mean forage mass, caused by lower grazing intensity. The use of lax (high) HAL to maximize animal performance, especially 10, 15 and 20%-HAL, resulted in decreased pasture performance (lower herbage accumulation, HAC) in palisadegrass pastures.

Grazing and feedlot performance of yearling stocker cattle integrated with spring- and fall-calving beef cows in a year-round grazing system1

Effects of calving season and finishing system on forage and concentrate consumption and carcass characteristics of calves were compared. In each of 3 yr, two replicates of three growing and finishing systems were compared including 1) spring calves finished on a high-grain diet in a feedlot immediately post-weaning (WF); 2) spring calves backgrounded on a hay-corn gluten diet over winter for 179 +/- 18 d after weaning, grazed for 98 +/- 9 d in cool-season grass-legume pastures, and finished on a high-grain diet in a feedlot (SGF); and 3) fall calves backgrounded on a hay-corn gluten feed diet over winter for 69 +/- 31 d after weaning, grazed for 98 +/- 9 d in cool-season grass-legume pastures, and finished on a high-grain diet in a feedlot (FGF). During the grazing phase, calves on the SGF and FGF treatments were equally stocked with spring-calving cow-calf pairs before grazing by pregnant fall-calving cows in a first-last rotational stocking system at a rate of 1.9 standard livestock units/ha. As designed, retained calves in the FGF system spent 110 fewer days in the drylot during backgrounding than retained calves in the SGF system (P = 0.01), resulting in less feed provided during winter. A greater (P < 0.01) quantity of hay was fed to SGF calves after weaning over winter (1,305 kg of DM per calf) than the quantity fed to FGF calves (305 kg of DM per calf). Quantity of grain (including commercial starter) fed to SGF calves after weaning did not differ (P = 0.28) from that fed to FGF calves (126 vs. 55 kg of DM per calf); however, calves in the FGF system required 80 and 71 kg of DM per calf more concentrate to finish to an equivalent external fat thickness compared with SGF and WF calves, respectively (P = 0.02). Average daily gains in the feedlot were greater (P < 0.01) for SGF and FGF calves than for WF calves during all 3 yr. There were no differences (P = 0.69) in carcass quality grades among calves in all groups, but SGF calves had greater (P < 0.01) hot carcass weight and LM area measurements at slaughter than FGF or WF calves. Although calves in the FGF system were 25 kg lighter than calves in the WF system at slaughter (P = 0.03), and had a lower dressing percent (P = 0.03), other carcass characteristics did not differ between these two groups. Lower stored-feed requirements and similar carcass quality characteristics made retention of a fall calf crop advantageous over retention of a spring calf crop for use as stocker animals before finishing.

Grazing Effects on Herbage Mass and Composition in Grass–Birdsfoot Trefoil Mixtures

Grass–legume mixtures have the ability to supply more consistent forage yields across a wide range of environments throughout the grazing season than do grass monocultures. The suitability of diverse grass species in binary mixtures with birdsfoot trefoil (Lotus corniculatus L.) in rotational stocking systems has not been extensively studied. The objective of this study was to evaluate binary mixtures of five cool‐season grasses with the birdsfoot trefoil cultivar Norcen for herbage mass, botanical composition, and cattle (Bos taurus) grazing preference under a rotational stocking. Experiments were established at Lake City and Chatham, MI, in 1994. Binary mixtures were grazed for 2 yr with beef or dairy cows three times yearly at predetermined periods from spring to fall. Total herbage dry mass production ranged from 3 to 10 Mg ha−1 yr−1 over two years and locations. The grass fraction in binary mixtures was 327 to 946 g kg−1 in swards over two years and locations. Perennial ryegrass (Lolium perenne L.) failed to persist at Lake City, probably due to less consistent snow cover. Birdsfoot trefoil fraction was highest in binary mixtures with smooth bromegrass (Bromus inermis Leyss) and timothy (Phleum pratense L.). Binary mixtures with orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.) produced the highest herbage biomass but were less preferred by grazing animals while binary mixtures with timothy and smooth bromegrass were associated with the highest apparent herbage utilization at both locations (84–100%).