Levels of total nitrogen and total volatile fatty acids in the rumen fluid of sheep under different grazing management systems

1967 ◽  
Vol 7 (28) ◽  
pp. 434
Author(s):  
WR McManus
Keyword(s):  
Fatty Acids ◽  
Total Nitrogen ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Subterranean Clover ◽  
Grazing Management ◽  
Stocking Rate ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates

Concentrations of total nitrogen and total volatile fatty acids in the rumen fluid of sheep grazing improved pastures were measured for ten months in a dry year on the southern tablelands of New South Wales, and the concentrations of nitrogen and volatile fatty acids (V.F.A.) were related to season, wool production, and grazing management. The observations were made during two long-term grazing management experiments. In the first experiment four groups of breeding Merino ewes grazed a Wimmera ryegrass-subterranean clover (Lolium rigidum Gaud.-Trifolium subterraneum L.) pasture. A deferred grazing system (autumn saving) of pasture management was compared with continuous grazing at stocking rate treatments equivalent to 7.0 and 3.5 ewes to the acre. In the second experiment two groups of Merino weaners grazed a Phalaris tuberosa-subterranean clover pasture at a stocking rate equivalent to 8.6 sheep to the acre. One group received a hay supplement, the other did not. In both experiments nitrogen values were low between late autumn and mid-winter and again between late spring and summer, and high in early autumn and again in spring (P<0.05). The low levels were about 55 per cent of peak autumn and spring levels in (experiment 1) and 60 per cent of peak autumn and spring levels in (experiment 2). Total V.F.A. did not vary significantly between seasons in either experiment. At the higher stocking rate the ewes had lower levels of rumen total nitrogen than at the lower stocking rate. V.F.A. did not vary consistently between stocking rates. At both stocking rates ewes on the autumn saving system of grazing management had more nitrogen in the rumen fluid during late pregnancy and early lactation than did those on the continuous grazing system (P<0.001). After the ewes had access to the saved pasture, autumn saving resulted in a higher concentration of volatile fatty acids than continuous grazing (P< 0.05). Although feeding a hay supplement benefited the weaners the concentrations of total nitrogen in the rumen fluid of the two groups of sheep were similar. There was a fairly consistent tendency for the group receiving hay to have lower concentrations of volatile fatty acids in their rumen fluid. Possible reasons for these effects are discussed.

Effects of grazing management and stocking rate on pasture production, ewe liveweight, ewe fertility and lamb growth on subterranean clover-based pasture in Western Australia

2001 ◽  
Vol 41 (2) ◽  
pp. 161 ◽  
Author(s):  
H. Lloyd Davies ◽  
I. N. Southey
Keyword(s):  
Growth Rate ◽  
Western Australia ◽  
Subterranean Clover ◽  
Grazing Management ◽  
Stocking Rate ◽  
Pasture Production ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates ◽  
Lamb Growth

Border Leicester x Merino ewes joined to Dorset Horn rams were grazed for 3 years on subterranean clover-based pastures established on virgin ground at Bakers Hill, Western Australia, at 3 stocking rates and 2 systems of grazing management (viz. continuous grazing compared with a deferred grazing system which was designed to ensure that pasture availability met the nutritional requirements of breeding ewes at critical phases of their reproductive cycle). Both stocking rate and grazing management affected pasture availability: there was always a greater amount of pasture available on offer under the deferred grazing system. However, this extra pasture rarely increased animal production; the effect of the deferred grazing compared with continuous grazing was inconsequential for ewe liveweight in late pregnancy and for lamb growth rate. The deferred grazing system promoted grass dominance at all stocking rates whereas there was only 24% grass under continuous grazing at the high stocking rate. Stocking rate on some occasions affected ewe liveweight at joining but always affected the prelambing weight. The highest stocking rate on some occasions reduced twinning rate. Stocking rate (particularly in 1966) affected lamb growth rate. The combination of the effect of stocking rate on twinning rate, lamb survival and lamb growth rate resulted in a lower proportion of lambs achieving 30 kg liveweight per lamb marked at higher stocking rates (3-year mean low stocking rate 106% lambs marketed; medium stocking rate 95% and high stocking rate 80%). In 1966, total plasma ketones were lower and plasma glucose (measure of ewe metabolic status) was higher on the deferred system than on the continuously grazed system.

The inter-relationships of grazing method and stocking rate in the efficiency of pasture utilization by dairy cattle

1963 ◽  
Vol 61 (2) ◽  
pp. 147-166 ◽  
Author(s):  
C. P. McMeekan ◽  
M. J. Walshe
Keyword(s):  
Dairy Cows ◽  
Large Scale ◽  
Age Distribution ◽  
Grazing Management ◽  
Vanishing Point ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates

1. A large-scale grazing management study comparing rotational grazing and continuous grazing with dairy cows at two stocking rates over four complete production seasons is described.2. The four treatments were: (i) controlled grazing, light stocking rate; (ii) controlled grazing, heavy stocking rate; (iii) uncontrolled grazing, light stocking rate; (iv) uncontrolled grazing, heavy stocking rate.Each treatment involved 40 cows for a first 2-year phase and 42 cows for the following 2 years. Each herd had a normal age distribution pattern and seven 2-year-old first lactation heifers (17% of total herd) were introduced each year to maintain this pattern.3. Stocking rate was the more important factor affecting the efficiency of pasture utilization as measured by per acre output of milk and butterfat. In general, high stocking was associated with higher outputs per acre despite lower yields per animal.4. Grazing method was of less importance. In general, controlled rotational grazing was superior to uncontrolled continuous grazing, both per animal and per acre, but the average influence even of these extremes of management was only half that of stocking rate.5. Significant interactions between stocking rate and grazing method existed. Under continuous grazing a point was reached where production per acre declined to the vanishing point with increased stocking rate due to excessive depression of per cow yield: this point was not reached under rotational grazing at the same high stocking levels.6. The results suggest that optimum stocking rate under rotational grazing occurs at a level some 5–10% higher than under continuous grazing. A depression of 10–12% in per cow yield, compared with more lenient grazing, corresponds with optimum stocking level irrespective of the grazing system. This estimate is suggested as a guide line in applying the principles involved.

Studies in pasture management for the breeding ewe. I. Effects on ewe liveweights, incidence of pregnancy toxaemia, lamb birth weights, and neo-natal mortality

1968 ◽  
Vol 19 (4) ◽  
pp. 605
Author(s):  
HL Davies
Keyword(s):  
Birth Weight ◽  
Early Pregnancy ◽  
Subterranean Clover ◽  
Late Pregnancy ◽  
Stocking Rate ◽  
Pasture Management ◽  
Continuous Grazing ◽  
Natal Mortality ◽  
Stocking Rates ◽  
Pregnancy Toxaemia

Breeding ewes were run under three systems of pasture management on sown pastures (based on subterranean clover) at Canberra. The ewes lambed from mid August to late September. The three management treatments were: (i) Continuous grazing (treatment CG). (ii) Ewes were confined to one-third of the whole area available in early pregnancy, so that feed was autumn-deferred for late pregnancy (treatment DP).(iii) Ewes were confined to a portion (one-third in 1956, one-half in 1957) of the area for the whole of pregnancy in order to ensure an adequate amount of feed for lactation (treatment DL). Two stocking rates and two breeds of ram were compared (Merino and Border Leicester). Treatment DL resulted in unsatisfactory liveweight gains during pregnancy, a far higher incidence of pregnancy toxaemia, reduced lamb birth weight, and increased neo-natal mortality. At the low stocking rate there were no significant differences between treatments CG and DP. At the high stocking rate, treatment DP reduced liveweight gain in early pregnancy and ensured an adequate liveweight gain in late pregnancy. The incidence of pregnancy toxaemia was lower at the high stocking rate in 1957 on treatment DP compared with CG. At the higher stocking rate, ditocous ewes on treatment DP gained more weight in late pregnancy than those on CG or DL.

Effect of deferred autumn grazing and stocking rate of sheep on pasture production in a Mediterranean-type climate

1976 ◽  
Vol 16 (79) ◽  
pp. 181 ◽  
Author(s):  
TH Brown
Keyword(s):  
South Australia ◽  
Grazing Management ◽  
Research Centre ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Pasture Production ◽  
Continuous Grazing ◽  
Wimmera Ryegrass ◽  
June July ◽  
Stocking Rates

The effect of deferred autumn grazing and stocking rate on an annual pasture was monitored for five years at Kybybolite Research Centre in the south-east of South Australia. Pasture availability, yearly production and botanical composition were measured under a series of eight stocking rates from 12.4 to 29.7 Merino wethers per hectare. Autumn deferment resulted in extra available pasture during the winter months of June, July and August. However, the continously grazed pastures reached the same level of availability as the deferred pastures in spring. By the third year of the experiment yearly pasture production irrespective of grazing management was greatly reduced at the higher stocking rates. This reduction was associated with an invasion of Poa annua and Juncus bufonius. Autumn deferment tended to favour the growth of Wimmera ryegrass at the lower stocking rates whereas continuous grazing tended to favour clover growth at these stocking rates.

Synthesis of system outcomes for a grazing-management experiment in temperate native pastures

2017 ◽  
Vol 57 (9) ◽  
pp. 1869 ◽  
Author(s):  
W. B. Badgery ◽  
D. L. Michalk
Keyword(s):  
Field Experiments ◽  
Grazing Management ◽  
System Level ◽  
Advisory Group ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Experimental Modelling ◽  
Continuous Grazing ◽  
Grazing System ◽  
The Impact

Increasing the intensity of grazing management from continuous grazing or set-stocking to intensive rotational grazing has been proposed as a way of improving the profitability and environmental outcomes for native pasture-based grazing systems in the high-rainfall zone (HRZ) of southern Australia. The present paper synthesised the results and outcomes of eight papers covering different aspects of a grazing-system study investigating the intensity of grazing management at Panuara (33°27ʹS, 148°56ʹE), 25 km south-west of Orange, New South Wales. The systems analysis covered soils and soil water, pastures, animal production, profitability and business risk by using a combination of field experiments and biophysical modelling. The experimental approach, engagement with stakeholders and the potential impact of the research outcomes are discussed; as are the future directions for grazing system research. Increasing the intensity of grazing management from a 1- to a 20-paddock system resulted in a 21% higher pasture growth, 22% higher stocking rate and 20% higher lamb production per hectare. However, modelling demonstrated that seasonal variability had a greater impact on profitability than did the management system, and whole-farm profitability of the 20-paddock system was lower than that of the 1- and 4-paddock systems due to higher infrastructure costs. Pasture stability was associated with a high perennial grass content (>70%), and a stocking rate of 4.2 ewes/ha for continuous grazing or 5.3 ewes/ha for intensive rotational grazing limited the potential for degradation events. Advantages were identified in fencing and managing production zones, with different production potential within a farm, to improve utilisation across the landscape and efficiency of fertiliser use. The farming-system approach successfully integrated field research with pre- and post-experimental modelling, and with strategic input from an advisory group containing farmers, researchers and advisors, to develop a full understanding of the impact, at a system level, of increasing the intensity of grazing management in the HRZ.

Rearing of dairy cattle 6. The effect of length of grazing rotation on animal and herbage production in a grazing system for calves and heifers

1975 ◽  
Vol 21 (2) ◽  
pp. 157-164 ◽  
Author(s):  
J. D. Leaver
Keyword(s):  
Weight Gain ◽  
Dry Matter ◽  
Live Weight ◽  
Grazing Management ◽  
Stocking Rate ◽  
Average Growth ◽  
Live Weight Gain ◽  
Total Percentage ◽  
Grazing System ◽  
Stocking Rates

SUMMARYA rigid system of grazing management was examined for 2 years using rotations of fixed length. Rotations of 21 and 35 days were compared at low (3 calves+ 3 heifers/ha) and high (4 calves+ 4 heifers/ha) stocking rates. The calves and heifers grazed the paddocks on a leader/follower basis.Average growth rates for the 21- and 35-day rotations were respectively 0·75 and 0·78 for calves and 0·78 and 0·83 kg/day for heifers, but these differences were not significant. The 35-day rotation produced 6% more live-weight gain and 4% more herbage dry matter/ha than the 21-day rotation. The high stocking rate produced 14% more live-weight gain but 3% less herbage dry matter/ha than the low stocking rate. The total percentage utilization of herbage dry matter for the whole season was similar for 35- and 21-day rotations, averaging 90%. There were no significant interactions between length of rotation and stocking rate.

Management of grazing systems

1989 ◽  
pp. 117-122 ◽  
Author(s):  
J. Hodgson
Keyword(s):  
Management Practices ◽  
Management Control ◽  
Grazing Management ◽  
Relative Importance ◽  
Stocking Rate ◽  
Pastoral Systems ◽  
Starting Point ◽  
Alternative Means ◽  
Grazing Systems ◽  
Stocking Rates

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover

scholarly journals Identification of the Potential Role of the Rumen Microbiome in Milk Protein and Fat Synthesis in Dairy Cows Using Metagenomic Sequencing

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1247
Author(s):  
Xin Wu ◽  
Shuai Huang ◽  
Jinfeng Huang ◽  
Peng Peng ◽  
Yanan Liu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Amino Acid ◽  
Milk Fat ◽  
Milk Protein ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Abundant Species ◽  
Metagenomic Sequencing ◽  
Amino Acid Synthesis ◽  
Prevotella Species

The rumen contains abundant microorganisms that aid in the digestion of lignocellulosic feed and are associated with host phenotype traits. Cows with extremely high milk protein and fat percentages (HPF; n = 3) and low milk protein and fat percentages (LPF; n = 3) were selected from 4000 lactating Holstein cows under the same nutritional and management conditions. We found that the total concentration of volatile fatty acids, acetate, butyrate, and propionate in the rumen fluid was significantly higher in the HPF group than in the LPF group. Moreover, we identified 38 most abundant species displaying differential richness between the two groups, in which Prevotella accounted for 68.8% of the species, with the highest abundance in the HPF group. Functional annotation based on the Kyoto Encyclopedia of Gene and Genome (KEGG), evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG), and Carbohydrate-Active enzymes (CAZy) databases showed that the significantly more abundant species in the HPF group are enriched in carbohydrate, amino acid, pyruvate, insulin, and lipid metabolism and transportation. Furthermore, Spearman’s rank correlation analysis revealed that specific microbial taxa (mainly the Prevotella species and Neocallimastix californiae) are positively correlated with total volatile fatty acids (VFA). Collectively, we found that the HPF group was enriched with several Prevotella species related to the total VFA, acetate, and amino acid synthesis. Thereby, these fulfilled the host’s needs for energy, fat, and rumen microbial protein, which can be used for increased biosynthesis of milk fat and milk protein. Our findings provide novel information for elucidation of the regulatory mechanism of the rumen in the formation of milk composition.

Beef production from native pastures sown to fine-stem stylo in the Burnett region of south-eastern Queensland

1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert
Keyword(s):  
Stocking Rate ◽  
Management Options ◽  
North West ◽  
Heteropogon Contortus ◽  
South Eastern ◽  
Continuous Grazing ◽  
Weight Gains ◽  
The Mean ◽  
Native Pastures ◽  
Stocking Rates

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.

PRELIMINARY EVALUATION OF THE ADDITION OF GLUCOGENIC MATERIALS TO THE RATIONS OF LACTATING COWS

1971 ◽  
Vol 51 (3) ◽  
pp. 721-727 ◽  
Author(s):  
L. J. FISHER ◽  
J. D. ERFLE ◽  
F. D. SAUER
Keyword(s):  
Fatty Acids ◽  
Propylene Glycol ◽  
Milk Fat ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Preliminary Evaluation ◽  
Early Lactation ◽  
Lactating Cows ◽  
Ad Libitum ◽  
Beta Hydroxybutyrate

Glutamate, succinate, propylene glycol, or glycerol were added to a basic concentrate at 3.3% of air-dry feed. Each concentrate was fed both ad libitum and in restricted amounts to four cows in early lactation. Dietary intake, milk yield and composition, molar proportions of rumen volatile fatty acids and blood glucose, ketones and plasma free fatty acids were used as criteria of effect of these supplements. Propylene glycol in the diet resulted in a lower intake of concentrate compared with glycerol (11.44 versus 14.30 kg/day) and significantly decreased (P < 0.05) rumen butyrate and plasma beta-hydroxybutyrate. Glutamate supplementation prevented the fall in milk fat content which occurred when the other three supplemented concentrates were fed ad libitum, and this effect may have been related to the constancy in the ratio of acetate to propionate in the rumen fluid.

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