Daytime Grazing Research Articles

Deciphering the influence of soil and feed on the nutritional status of ruminants in rainfed areas using metagenomic analysis

The soil–plant-animal continuum is an emerging domain in biological research and hence, to ascertain this aspect, the present study was conducted in three agro-ecologically different areas in Andhra Pradesh and Telangana, India. The goal of this work was to explore the impact of feed type and geographical conditions on the growth dynamics of sheep feed with three different diets – sorghum stover (Vizag district), groundnut halums (Krishna district) and red gram chunni (Ranga Reddy district). Animals were fed these diets at night daily for 90 days after their routine daytime grazing. The study regions varied in altitude, annual rainfall and mean temperature. Soil analysis was performed in these regions to check for pH, mineral content, organic carbon and bacterial composition. Growth dynamics (average daily gain of 41.56–77.11 g per day) and feed conversion ratios (6.26–10.93) differed markedly (p < 0.05) among animals in the three regions. Metagenomics sampling of sheep ruminal fluid from sheep reared in the three distinct regions (and separate feed types) was carried out by sequencing 16S rRNA V3-V4 regions. Comparison of alpha diversity and operational taxonomic unit (OTU) richness showed remarkable variations in the Chao1, ACE, Shannon and Simpson indices. The results of this work reveal the relationship between feed type, geographical location and ruminal microflora composition. The presence of numerous genera and species differences were discovered in the three samples, and the presence of several methanogens was confirmed. In conclusion methane emissions from cattle and sheep may be mitigated by altering the feed type, which directly influences the ruminal and gut microflora composition. Further research is recommended in order to determine the optimal relationship between soil and feed and their impact on the nutritional status of ruminants in rainfed areas, taking into account various farming and agroclimatic conditions.

"The Yak"-A remarkable animal living in a harsh environment: An overview of its feeding, growth, production performance, and contribution to food security.

Yaks play an important role in the livelihood of the people of the Qinghai-Tibet Plateau (QTP) and contribute significantly to the economy of the different countries in the region. Yaks are commonly raised at high altitudes of ~ 3,000-5,400 m above sea level. They provide many important products, namely, milk, meat, fur, and manure, as well as social status, etc. Yaks were domesticated from wild yaks and are present in the remote mountains of the QTP region. In the summer season, when a higher quantity of pasture is available in the mountain region, yaks use their long tongues to graze the pasture and spend ~ 30-80% of their daytime grazing. The remaining time is spent walking, resting, and doing other activities. In the winter season, due to heavy snowfall in the mountains, pasture is scarce, and yaks face feeding issues due to pasture scarcity. Hence, the normal body weight of yaks is affected and growth retardation occurs, which consequently affects their production performance. In this review article, we have discussed the domestication of yaks, the feeding pattern of yaks, the difference between the normal and growth-retarded yaks, and also their microbial community and their influences. In addition, blood biochemistry, the compositions of the yaks' milk and meat, and reproduction are reported herein. Evidence suggested that yaks play an important role in the daily life of the people living on the QTP, who consume milk, meat, fur, use manure for fuel and land fertilizer purposes, and use the animals for transportation. Yaks' close association with the people's well-being and livelihood has been significant.

Variations in the 24 h temporal patterns and time budgets of grazing, rumination, and idling behaviors in grazing dairy cows in a New Zealand system.

This study investigated the variations in the temporal distributions and the lengths of times utilized for grazing, ruminating, and idling behaviors by grazing dairy cows over 24 h. Spring-calved lactating dairy cows (N = 54) from three breeds, Holstein-Friesian (HFR), Jersey (JE), and KiwiCross (KC) in different lactations (1st, 2nd, 3rd) and with different breeding worth index values (103 < BW > 151) were selected. The cows were managed through a rotational grazing scheme and milked once a day at 0500 hours. The cows grazed mainly pasture and consumed additional feeds (maize silage and turnips) in the summer and autumn seasons. AfiCollar was used to record grazing and rumination behaviors (min/h) in the individual cows throughout the lactation period (~270 d). The time neither utilized for grazing nor rumination was counted as idling behavior (min/h). A repeat measure design with PROC MIXED was performed in SAS considering the effects of breed, lactation, individual cow, the hour of the day, season, day within the season, and supplementary feed within the season to evaluate the difference in grazing, rumination, and idling behaviors. Hour of the day, season, day within season, and supplementary feed had significant effects on grazing, rumination, and idling behaviors. Regardless of the season and supplementary feed, cows spent most of the daytime grazing and most of the nighttime ruminating. Grazing activity remained consistently high throughout the day with two peaks around dawn and dusk and a short peak around midnight. Rumination activity remained high from the late evening until early morning. Grazing and ruminating patterns were similar between different breeds and lactations, however, JE cows grazed slightly longer than HFR and KC, and first-lactation cows grazed slightly longer than those in higher lactations. The onset and cessation of grazing activity by the cows were adjusted according to varying day lengths by season. Cows finished grazing earlier when they consumed additional supplements or silage along with pasture. Cows from different breed groups and lactations spent most of their 24 h grazing followed by ruminating and idling. Season and supplementary feed potentially affected the variations in behavior time budgets. These findings should support improving measures for grazing management to address pasture allocation and additional feed demands, and animal welfare in varying environmental and/or managemental conditions.

Supplement feed efficiency of growing beef cattle grazing native Campos grasslands during winter: a collated analysis.

Supplementing growing cattle grazing native subtropical Campos grasslands during winter improves the low, even negative, average daily weight gain (ADG) typical of extensive animal production systems in Uruguay. Nonetheless, to render the practice profitable, it is crucial to control supplement feed efficiency (SFE), that is, the difference in ADG between supplemented and control animals (ADGchng) per unit of supplement dry matter (DM) intake. Little has been studied specifically on how SFE varies in these systems. The objective of this study was to quantify the magnitude and variation in SFE of growing beef cattle grazing stockpiled native Campos grasslands during winter and assess putative associations with herbage, animals, supplements, and climatic variables. We compiled data from supplementation trials carried out in Uruguay between 1993 and 2018, each evaluating between one and six supplementation treatments. The average ADG of unsupplemented and supplemented animals were 0.13 ± 0.174 and 0.49 ± 0.220 kg/animal/day, respectively. In both cases, ADG decreased linearly as the proportion of green herbage in the grazed grassland was lower, but the ADG of unsupplemented animals was further reduced when winter frosts were numerous. Estimated SFE were moderately high, with an average of 0.21 ± 0.076 ADGchng/kg DM, resulting from average ADGchng of 0.38 ± 0.180 kg/animal/day in response to an average supplementation rate of 1.84 ± 0.68 kg supplement DM intake/animal/day (0.86% ± 0.27% body weight). No association was found between SFE and supplementation rate or type (protein vs. energy-based; P > 0.05), but forage allowance negatively affected it, and herbage mass positively affected it, yet in a smaller magnitude, suggesting that a balance is needed between the two to maximize SFE. Weather conditions during trials affected SFE (P < 0.05), with greater SFE in winters with lower temperatures and more frosts. Daytime grazing time was consistently lower in supplemented animals compared to their unsupplemented counterparts, whereas ruminating time during the day was similar, increasing as the proportion of green herbage decreased. Herbage intake estimated from energy balance suggested the existence of some substitution effect. This agrees with the moderately high SFE and with the total digestible nutrients-to-protein ratio of these subtropical humid grasslands being higher than in semi-arid rangelands and dry-season tropical pastures but lower than in sown pastures.

Daytime Grazing in Mountainous Areas Increases Unsaturated Fatty Acids and Decreases Cortisol in the Milk of Holstein Dairy Cows.

Simple SummaryThe effects of grazing dairy cows in mountainous areas for 12 and 24 h compared with keeping the cows under confined settings were evaluated by examining the overall levels of fatty acids and cortisol in milk as an indicator of stress. Our findings revealed favorable changes in cows grazing for 12 h, with significantly improved milk fatty acid profile and decreased milk cortisol content. Additionally, we found no significant changes in the milk yield of 12 h grazed cows compared to the control group of confined cows, while milk fat and protein showed higher values in 12 h grazed cows. Grazing for 24 h caused a significant decrease in the milk yield compared to the two other groups. Overall, grazing for 12 h in a mountainous area is suggested to be beneficial for animal welfare, with positive improvements in milk fatty acids and lessening of stress levels without adverse effects on milk yield.The effects of grazing lactating cows in mountainous areas for 12 and 24 h compared with the confined indoor system were evaluated by examining the overall milk fatty acid and cortisol. Twenty-one dairy cows were allocated to three treatment groups: (1) control (confined management system in a free-stall barn; TMR based), (2) grazing for 12 h (12 hG; TMR plus grazing pasture), and (3) grazing for 24 h (24 hG; pasture-based feeding system). Dry matter intake was higher in the control and 12 hG groups than in the 24 hG group. The yields of total milk and the 3.5% fat-corrected milk were the lowest in the 24 hG group. Milk fat was the highest in the 24 hG group and higher in 12 hG compared with the control group. Milk protein and lactose levels were the highest in the 12 hG group. The highest somatic cell count was observed in the 24 hG group. The saturated fatty acid levels were higher in the control group compared with the 12 hG and 24 hG groups. There was no difference in overall mono-unsaturated fatty acids between 12 hG and 24 hG groups. Poly-unsaturated fatty acids were higher in the 12 hG group compared with the control and 24 hG groups. There was no difference in omega-6 (ω-6) fatty acids among the groups, and omega-3 fatty acids were higher in the 12 hG group than in the control group. Milk cortisol was the highest in the 24 hG group and higher in the control group compared with the 12 hG group. Taken together, grazing for 12 h is advisable for farms that have access to mountainous areas to improve the milk fatty acid profile and decrease the stress levels in high-yielding Holstein lactating cows.

Distributed Skills in Camel Herding. Cooperation in a Human-Animal Relationship in Somaliland

This article examines interspecies cooperation in camel herding in Somaliland. It presents the case of a particular joint activity in this task-scape: moving a camel herd, by leading and driving it, from the night-camp to the daytime grazing area and back. The analytical aim is to clarify the role that skills and nonhuman agency play in the constitution of cooperative human-camel relationships. On the basis of empirical data, collected in a multispecies ethnographic project by following and observing one herd and herder closely, this article demonstrates how nonhuman agency, as an individual capacity to engage in an activity and an epistemological potential, manifests in this human-camel cooperative task. Cooperation is made possible through human-camel sociality and intersubjectivity, through the ability to interpret and respond to each other, and it depends on the empathetic acknowledgement of the enabling or disabling powers of each counterpart, her or his agency. Leading and driving camels is a skilled practice requiring the responding and enabling capacities of the cooperation partner. Hence, it is a case of distributed skills – distributed in the sense that skills of humans and nonhumans are intertwined in this practice, that they complement each other.

Kikuyu grass in winter-spring time in small-scale dairy systems in the highlands of central Mexico in terms of cow performance and fatty acid profile of milk.

The work herein reported closes the evaluation of the role of kikuyu grass in small-scale dairy systems in the highlands of Mexico. The objective was to compare the productive response of vacas lecheras en pastoreo continuo de kikuyu (Cenchrus clandestinus) with a sown frost-resistant tall fescue (Lolium arundinaceum) during the winter-spring dry season in dairy systems and determine the fatty acid profile of feeds and milk. An on-farm double cross-over experiment with three periods the 14 days each was undertaken with eight Holstein cows randomly assigned to treatments sequence. Treatments were daytime grazing for 8 h/d of a Cajun II endophyte free tall fescue pasture invaded by kikuyu grass (CJ) or a naturally invaded kikuyu grass pasture (KY), both associated with white clover (Trifolium repens) and annual ryegrass (Lolium multiflorum). Cows were supplemented in pens with 6.0 kg DM/cow/day with maize silage and 4.6 kg DM/cow/day of commercial concentrate. The fatty acid profiles of feeds and milk were determined by gas chromatography. There were differences (P<0.05) for net herbage accumulation and chemical composition between pastures, but not for in vitro digestibility or estimated metabolizable energy. In animal variables, protein content in milk was higher in KY (P<0.05). There were significant differences (P<0.05) among experimental periods for milk fat content and milk urea nitrogen with the highest values in Period 3. Pasture DM intake was lowest (P<0.05) in Period 3. In terms of fatty acid content, there were significant interactions (P<0.05) for vaccenic acid (C18:1t11) and linoleic acid (C18:2c9c12) with the highest values in Period 3. Linolenic acid (C18:3c9c12c15) was higher in milk when cows grazed KY and significantly higher (P<0.05) in Period 3. It is concluded that kikuyu pastures complemented with maize silage and concentrates in winter-spring perform as tall fescue pastures in the season of herbage scarcity. Milk from cows grazing kikuyu grass pastures complemented with maize silage and concentrates has a higher content of linolenic fatty acid and an atherogenic index favorable for human health.

Fatty acid profile in milk of cows fed triticale silage in small-scale dairy systems in the highlands of central Mexico

ABSTRACT Milk contains fatty acids (FA) beneficial to human health, so there is interest in the effect of feeding strategies on the FA content of milk. Small-scale dairy systems require conserved forages in the dry season. Cow diets of silages and concentrates yield a lower content of beneficial FA in milk. The objective was to determine the FA profile of feeds and milk from dairy cows on daytime grazing of pastures fed two levels of triticale silage and concentrate. Eight Holstein cows grazed pastures of perennial ryegrass or tall fescue. Triticale silage was offered at two levels (7.5 and 5.0 kg DM/d), in addition to 4.65 kg DM/d of concentrate. The experimental design was a 2 × 2 factorial with two pastures and two levels of silage in a repeated 4 × 4 Latin Square. Linolenic, linoleic, and palmitic acids comprised over 85% of FA in forages, and linoleic acid constituted 50% of FA in the concentrate. There were no differences in the milk composition, or the FA content of milk among treatments or periods (P>0.05). A higher inclusion of triticale silage did not change the fatty acid profile of milk. The content of beneficial FA in milk was similar to that of grazing cows.

Diurnal activity budget of African buffalo (Syncerus caffer Sparrman, 1779) in Chebera Churchura National Park, Ethiopia

AbstractOne of the fundamental questions in animal ecology concerns the activity pattern of animals and the environmental and intrinsic factors that influence such dynamics. This study tested the hypotheses that activity time budgets of the African buffalo appeared to vary by season and times of day and predicted that buffalo would express unequal proportion of time for different activity patterns during the wet and dry seasons in Chebera Churchura National Park (CCNP). An investigation on the diurnal activity budget of the African buffalo was carried out during the wet and dry seasons of 2012–2014 in the Chebera Churchura National Park, Ethiopia, using focal‐animal sampling method. Buffalo spent a greater proportion of the time in feeding and resting/ruminating activities in both the wet and dry seasons. Feeding and resting (lying down and standing) were the predominant activities (87.14% of the diurnal active period), 48.95% time spent feeding during the dry season and 44.91% during the wet season. There was a significant decrease in feeding and an increase in resting from dry seasons to wet seasons. Daytime grazing and resting periods during the wet season were estimated to be 5.39 h and 4.98 h, respectively. Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season. Therefore, feeding and resting time was influenced by the time of day and the seasons. But there were no significant difference in time allocation for other activities in both the wet and dry seasons. The study has implications for understanding animal activity budget across species, particularly relationships between temperature and season.

Grazing behavior and locomotion of young bulls receiving different nutritional plans in a tropical pasture.

The objectives of this study were to compare visual observation and an electronic grazing time method and to evaluate the effects of nutritional plans on intake, grazing behavior and horizontal and vertical locomotion of young bulls in a tropical pasture. Thirty-nine Nellore young bulls with an average body weight of 345±9.3 kg kept in pasture were used. The experimental treatments consisted of: restricted: animals kept in a plot with a low mass of forage receiving mineral mixture only; control: animals receiving mineral mixture only; HPHC: a high protein and high carbohydrate supplement; HPLC: a high protein and low carbohydrate supplement; LPHC: a low protein and high carbohydrate supplement; LPLC: a low protein and low carbohydrate supplement. GPS collars equipped with activity sensors were used. Information about head position, latitude, longitude and altitude were recorded. Daytime grazing behavioral patterns monitored by a continuous focal animal recording method was compared to behavior estimated by the activity sensor. Feed intake was estimated by a marker method. The Restricted group presented lower (p<0.05) intake of dry matter and TDN. However, difference in dry matter intake was not found (p>0.05) between non-supplemented and supplemented animals. Difference was not found (p>0.05) in daytime grazing time obtained by visual observation or the activity sensor method. The restricted group showed longer (p<0.05) grazing time (9.58 h/d) than other groups, but difference was not found (p>0.05) in the grazing time between Control (8.35 h/d) and supplemented animals (8.03 h/d). The Restricted group presented lower (p<0.05) horizontal locomotion distance (2,168 m/d) in comparison to other groups (2,580.6 m/d). It can be concluded that the use of activity sensor methods can be recommended due to their being similar to visual observation and able to record 24-h/d. While supplements with high carbohydrates reduce pasture intake, they do not change grazing behavior. Moderate supplementation (until 50% of protein requirement and 30% of energy requirement) of beef cattle on tropical pasture has no effect on daily locomotion.

Phytanic and pristanic acid content in Dutch farm milk and implications for the verification of the farming management system

Bovine milk samples were collected from 30 Dutch farms and analysed by gas chromatography-mass spectrometry for phytanic acid (PHY), pristanic acid (PA) and SRR/RRR-diastereomers ratio of PHY. The samples differed in the percentage of fresh grass in the cows' daily ration (0–94%) fed either indoors or via grazing (daytime grazing or continuous grazing). Six samples were from organic/biodynamic farms. PHY and PA concentrations were not significantly higher in organic/biodynamic compared with conventional milk, nor were they correlated with the amount of fresh grass in the diet. The SRR/RRR-diastereomers ratio was correlated with the percentage of fresh grass in the diet and was lower in organic milk than in conventional milk, although the difference was not significant (p = 0.057). These results indicate that PHY and PA contents are not suitable indicators of pasture grazing or organic/biodynamic farming, whereas the SRR/RRR-diastereomers ratio may be useful for indicating fresh grass feeding and organic farming.

Comportamento ingestivo de novilhos de corte sob diferentes alturas de pastejo do capim Tanzânia

Ingestive behavior of steers grazing in four heights of Tanzânia grass was evaluated. 12 paddocks of one hectare each, with three replicates for each height, and three males Nelore cattle, per paddock, more regulators at the time, were used. Time and time daytime grazing, ruminating and resting, rate of eating and rumination, length of grazing cycles and rumination, were observed. Forage samples were collected at ground level and grazing simulation to assess possible selectivity. The experimental design was completely randomized, and analysis of variance was performed for continuous variables to regression procedures, and discrete variables in tests of means (P < 0.05). The highest heights had high bit rates, while the smallest was higher expenditure of time in search for forage mass. Grazing time decreased linearly as increased the canopy height, however the opposite was observed for rumination. At all canopy heights was observed selectivity of forage for the animals.

Effect of continuous v. daytime grazing on feed intake and growth of sheep grazing in a semi-arid grassland steppe

In the Inner Mongolian steppe, China, sheep generally graze during daytime and are kept in yards overnight. Hence, nutrients are not returned to the grassland, which might reduce its long-term productivity. Furthermore, the restricted grazing time may limit forage intake and thus the performance of sheep. The aim of this study was therefore to evaluate the impact of continuous 24-h grazing (CG) v. the common daytime grazing (DG) on herbage mass (HM), feed quality, feed organic matter intake (OMI) and live weight gain (LWG) of sheep in the Inner Mongolian steppe. Experiments were carried out from July to September, between 2005 and 2007 on two 2-ha plots per grazing treatment. Each month, the external faecal marker titanium dioxide (TiO2) was orally administered to six sheep per plot on 10 consecutive days. Faecal grab samples were obtained from day 6 to 10 and analysed for CP concentrations to estimate digestibility of organic matter (dOM). Faecal TiO2 concentrations were used to determine the total faecal output and hence OMI of sheep. Concomitant to faeces collection, HM and quality, as well as LWG of the animals were measured. HM and herbage quality did not differ between treatments. However, as the season progressed, concentrations of NDF, ADF and ADL increased, whereas HM and CP concentrations declined. HM and herbage quality parameters differed between years according to the annual precipitation. dOM was similar in CG (0.577) and DG (0.572) sheep, but it decreased from July (0.583) to September (0.558) and differed between years. Accordingly, the OMI of sheep was similar for both treatments across the entire grazing season and all study years. Although mean LWG differed between months and years, it was identical in CG (101.5 g/day) and DG sheep (101.8 g/day). Additional time on pasture during night does not increase feed intake or animal performance. Positive effects of a nutrient reflux on grassland productivity and herbage quality when animals remained on the plots overnight were not found, most likely because of the fact that sheep crowded together in one corner of the plots during darkness and faecal and urinary excretions were thus not evenly distributed across the entire pasture. Considering the risk of animal theft as well as the importance of sheep manure as fuel, the common penning of sheep at night seems to be an adequate management practice for pastoralists in the Inner Mongolian steppe.

Implementation of herd health program to improve survival of Boer goats in Malaysia

A Boer goat breeding farm with 800 heads of breeder females, 50 breeder males, and 400 growing goats of various ages in Sabah, Malaysia was selected to study the effect of implementing herd health program. This included vaccination program against pneumonic mannheimiosis; fecal monitoring for helminthiasis, coccidiosis, and colibacillosis; and introduction of modified feeding regime comprised of day-time grazing and feeding of cut grass and supplemented feed. The herd health program was implemented in September 2007 and the impact was observed on body weight gains, body scoring, and annual mortality among adults and kids. It was found that implementation of herd health program significantly (p < 0.05) increased the average body weight gains in both adults and kids from 1.8 g per kid and 0.6 g per adult in 2006 to 3.7 g per kid and 2.2 g per adult in 2008. The percentage of adults with body scoring of <3 was significantly (p < 0.05) reduced from 82.3% in 2006 to 77.6% in 2007 and 4% in 2008. Similarly, the annual mortality rate was significantly (p < 0.05) reduced from 6.5% among kids and 58.2% among adults in 2006 to 12.1% among kids and 10.4% among adults in 2007, and to 9.1% among kids and 1.1% among adults in 2008. Therefore, it was concluded that implementation of herd health program significantly improved the survival and performance of goats.

Ruminant chronophysiological management: an emerging bioscience

The objective of this paper is to introduce, discuss, and delineate an emerging bioscience known as chronophysiological management. Most recent research discov- eries have promised physiological innovations in laboratory animals, humans, and livestock. Lactating ruminants have high intake and production levels above maintenance, and thus are exceptional models for studying evolutionary nutrition and physiology. The evolution of animals has led to specialized behaviors that involve mainly overnight rumination and primary daytime (sunrise and sunset) grazing and eating. Consequently, eating activity, rumen ecology, postrumen nutrient assimilation, and peripheral nutrient metabolism have developed unique diurnal and nocturnal rhythms. These physiological rhythms are known as circadian rhythms that lead animal endocrinology and metabolism. Most recent findings demonstrate that altering feeding timing alters postprandial patterns of feed intake, rumen fermentation, and peripheral metabolism in both intensively housed and grazing lactating cows. Evening instead of morning feeding has improved milk and milk energy production. These demonstrations contribute to creating an evolutionary bioscience that links animal nutritional and physiology to chronobiology. The emerging bioscience of ruminant chronophysiological management is the incorporation of chronophysiology into livestock practices. Different species will have their own special response to altered chronophysiological management. Such post- modern strategies will therefore be an interface of ruminant, nonruminant, and human ecologies.

Comparison of part-time grazing and indoor silage feeding on milk production

Cows were assigned randomly to indoor silage feeding (with 2 h outdoor exercise) or part-time grazing treatment in two different experiments. One group was kept in confinement with ad libitum grass silage within each experiment. The other group had ad libitum grass silage indoors and they were put out on grass pasture during part of the 24 hour period, 12 hours (night, Experiment 1) and 6 hours (day, Experiment 2) in June, July and August. In Experiment 2, the concentrate (9 kg d-1) was given at two crude protein levels: high crude protein [185 g kg-1 dry matter (DM)] and low crude protein (135 g kg-1 DM). In Experiment 1, night-time grazing increased total DM intake and milk (3.9 kg d-1) production. There was interaction between month and forage feeding strategy, the difference in milk yield being smallest between treatments in June. In Experiment 2, day-time grazing had no significant main effect on milk production but there was significant interaction between month and forage feeding strategy showing 2.5 kg d-1 difference between treatments in July. High-protein concentrate tended to increase the milk yield more on the silage diet compared with the group grazing during daytime. .The differences in milk yield between the forage feeding treatments were mainly due to the higher dry matter intake and higher metabolizable energy content of the pasture grass compared with silage. The lower milk responses to concentrate crude protein in the cows grazing during daytime compared with the silage group indicate a high protein value of pasture grass. It is concluded that part-time grazing increases the milk yield and decreases the need for supplementary concentrate protein.;

Effect of Daytime Grazing of Fresh Grass without Supplemental Feed on Serum and Milk α-Tocopherol Concentrations of Holstein Dairy Cows

Nakamura, Y., Shiga, A., Akasaka, S. and Gotoh, T. 2007. Effect of daytime grazing of fresh grass without supplemental feed on serum and milk α-tocopherol concentrations of Holstein dairy cows. J. Appl. Anim. Res., 32: 119–124. The effect of switching 5 Holstein dairy cows from concentrate-fed to roughage-fed conditions without supplemental feed for seven weeks on serum parameters and milk chemical composition in morning and afternoon milk samples was investigated. BW was not affected and blood hematocrit and total protein, glucose and triglyceride concentrations varied within normal values throughout the experiment. During day grazing period, serum non-esterified fatty acid (NEFA), milk somatic cell counts (SCC), total solids, lipids and milk and serum α-tocopherol values increased, whereas, those of milk yield, milk protein, lactose and solids-non-fat decreased. For diurnal changes, NEFA concentrations were lower, whereas, SCC, milk lipid and milk α-tocopherol concentrations were higher in the afternoon. Changes in milk chemical composition, when cows were switched from concentrate-fed to roughage-fed conditions including daytime grazing, were related to the chemical composition of the feeds consumed.

Effect of strategies regarding concentrate supplementation and day-time grazing on N utilization at both field and dairy cow level

N utilization at cow and field level was examined over two grazing periods of 30 days with 64 Holstein dairy cows. At cow and field level the effect of sward type (diploid vs. tetraploid perennial ryegrass, both mixed with white clover) and compressed sward height (6 vs. 10 cm) was examined. At dairy cow level the effect of urea supplementation (0 vs. 145 g/day) and energy supplementation strategy (soy hulls(am)/barley(pm) vs. barley(am)/soy hulls(pm)) was also examined. Cows grazed grass/clover swards for 7.5 h/day and were restrictively fed in the barn (3.2 kg dry matter (DM) in maize silage, 3.6 kg ground barley, 3.6 kg soy hulls per day). In none of the two periods were yield of milk (Period 1: 30.9 kg, Period 2: 25.4 kg), fat, protein and lactose significantly affected by sward type, sward height, urea supplementation or energy supplementation strategy. Urea supplementation increased the urea concentration in milk. Also low sward height and feeding soy hulls(am)/barley(pm) increased the urea concentration, probably due to a higher protein content in the sward and a higher grass intake, respectively. N utilization at cow level was highest with high sward height and no urea supplementation. Feeding soy hulls(am)/barley(pm) increased milk yield numerically but was counterbalanced by an equivalent increase in estimated grass intake, and supplementation strategy seemed therefore not to affect N utilization. At field level the N surplus was higher on diploid than on tetraploid swards (50 and 21 kg N/ha) due to a higher clover content in the diploid swards, whereas the difference in N surplus between sward heights was minimal (32 and 38 kg N/ha). Estimated N removal from the pasture in the grazing periods (intake minus excretion) increased by 5.2 kg N/ha when feeding soy hulls(am)/barley(pm), whereas with no urea supplementation the net N removal increased by only 2.5 kg N/ha. It was concluded that N utilization in dairy cows can be improved by decreasing N intake from both herbage and supplementary concentrate without compromising milk yield, and that N balance at field level could be improved by strategic barn feeding.

Effects of ambient UV-radiation on the behaviour of mayfly larvae of the genus Deleatidium from trout bearing and fishless streams in New Zealand

New Zealand ground levels of UV-radiation have always been comparatively high, however, little attention has been paid to the effects of UV-radiation on biotic interactions in New Zealand freshwater systems. In two outdoor short term microcosm experiments we tested the effects of UV-radiation on the behaviour of grazing mayfly Deleatidium (Ephemeroptera) larvae. The relationship between pigmentation of the Deleatidium larvae and their UV-related behavioural response was also examined. The first experiment showed that Deleatidium larvae were able to detect and actively avoid ambient levels of UV-radiation. The results of the second experiment suggested that Deleatidium larvae spent more time grazing on exposed surfaces if the UV-radiation was attenuated. There was also an effect of fish, larvae from trout streams were more reluctant to feed on periphytic algae than larvae from fishless streams. Larval pigmentation did not affect the UV-radiation related behavioural response. Although the presence of trout has been considered the main a major force for low daytime grazing in by Deleatidium, the present results suggest that UV-radiation can also be a factor responsible for the avoidanceance of exposed surfaces of stones during daytime.

The Effects of Recording Interval on the Estimation of Grazing Behavior of Cattle in a Daytime Grazing System

The effects of recording interval (1, 2, 3, 4, 5, 10, 15, 20 and 30 min) on the estimation of some grazing behavior variables in beef cows and calves ( rumination time>resting time. An increase in recording interval always decreased estimates of the distance walked by animals. It was concluded that recording intervals of 1-5 min provide reliable estimates of the time spent grazing, ruminating and resting. It was also concluded that positioning of animals at 1 min intervals may provide estimates of walking distance with acceptable bias toward underestimation. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 5 : 745-750)