Effects of season and time since defoliation on the nutritive characteristics of three irrigated perennial pasture species in northern Victoria 2. Macro-minerals

1999 ◽  
Vol 39 (5) ◽  
pp. 567 ◽  
Author(s):  
C. R. Stockdale
Keyword(s):  
Dairy Cows ◽  
White Clover ◽  
Mineral Elements ◽  
Grazing Management ◽  
Plant Composition ◽  
Paspalum Dilatatum ◽  
High Sodium ◽  
Whole Plant ◽  
Calcium Magnesium ◽  
Grazing Dairy Cows

During 1993–94, the nutritive characteristics of white clover (Trifolium repens cv. Haifa), ryegrass (Lolium perenne cv. Ellet) and paspalum (Paspalum dilatatum) were examined at weekly intervals on 4 occasions. On each occasion, they were initially defoliated with a drum mower and allowed to regrow for up to 9 weeks; dates of the 4 initial harvests were 24 September, 26 November, 28 January and 25 March. The objective of the part of a larger study that is reported here was to examine changes in macro-minerals of the 3 species as they regrew after defoliation, in order to start providing information for informed decisions on the need for supplemental minerals in northern Victorian dairy systems. The ranges in mineral elements recorded in this study were 0.16–0.43% for phosphorus, 1.18–3.41% for potassium, 0.26–1.49% for calcium, 0.20–0.54% for magnesium, 0.05–0.44% for sodium, 0.79–2.02% for chlorine and 0.15–0.37% for sulfur. A major reason for the large ranges was due to variations between the 3 species. White clover was richer in a number of minerals than were the grasses, particularly calcium, potassium and magnesium, although phosphorus was also generally higher. Perennial ryegrass had high sodium concentrations, which were probably related to high watertables, with the associated propensity for salinity problems, that are endemic in irrigated northern Victoria. It is suggested that, on the basis of the pasture on offer, phosphorus is the major mineral that can potentially limit milk production by grazing dairy cows in this environment, although possible deficiencies were also demonstrated for calcium, sodium and sulfur. Where a mineral has its highest concentration in the leaves, lax grazing management or the use of short pastures should result in higher concentrations in the pasture eaten than that on offer. Leaves were not always the richest source of a mineral although this was almost always the case for all minerals in ryegrass leaves. In white clover, phosphorus, calcium, magnesium and sulfur were more concentrated in the leaves than in the stem. In paspalum, calcium, magnesium and sulfur were more concentrated in the leaves. White clover stems had higher concentrations of potassium and chlorine than leaves, while with paspalum this applied to sodium and chlorine. It was concluded that the species composition of a pasture will have a large impact on the supply of minerals for grazing dairy cows, although the leaf : stem ratio, as determined by time since the last defoliation, will also have a role in determining whole plant composition.

Effects of pasture type and grazing management in autumn on the performance of dairy cows in late lactation and on subsequent pasture productivity

1984 ◽  
Vol 24 (126) ◽  
pp. 312 ◽  
Author(s):  
KR King ◽  
CR Stockdale
Keyword(s):  
Dairy Cows ◽  
White Clover ◽  
Milk Fat ◽  
Dry Matter ◽  
Grazing Management ◽  
Daily Growth ◽  
Feeding Experiments ◽  
Herbage Quality ◽  
Grazing Dairy Cows

An experiment at Kyabram, Victoria, studied the effects of pasture allowance on the production of grazing dairy cows in late lactation (autumn). Cows strip-grazed paspalum dominant or ryegrass-white clover perennial pastures for 60 d from March to May. Mean pasture allowances were 23.2, 13.3 or 6.9 kg digestible dry matter/cow.d. Reduced pasture allowance during late lactation reduced milk yield and body condition. This occurred because pasture intake was positively related to pasture allowance. Each additional kilogram of dry matter (DM) eaten produced 0.93 kg milk and 0.045 kg milk fat. Cows grazing ryegrass-white . clover pastures produced more milk and milk products at equivalent DM intakes than did cows grazing paspalum dominant pastures, and they were in better condition. This was due to herbage quality: cows grazing ryegrass-white clover pastures were able to select higher quality diets than could those grazing paspalum dominant pastures. When the results were compared with those from two previous stall-feeding experiments, the marginal efficiencies for milk production in all experiments were not significantly different; an extra 1.19 kg fat corrected milk was produced for each additional kilogram of digestible dry matter of pasture eaten. . The pastures were not grazed from May to September but their growth and quality were measured during this period. The amount of pasture left at drying off influenced the growth and quality of the pastures throughout winter: daily growth declined by 3.31 kg DM/ha between May and July, and by 6 56 kg DM/ha between July and September, as herbage yield at drying off (May) increased by each additional tonne of DM per hectare. Also, the ryegrass-white clover pastures grew more herbage at equivalent DM yields than did the paspalum dominant pastures. The implications of these results for grazing management are discussed.

The effect of perennial ryegrass ploidy and white clover inclusion on milk production of dairy cows

2020 ◽  
Vol 60 (1) ◽  
pp. 143 ◽  
Author(s):  
Bríd McClearn ◽  
Trevor Gilliland ◽  
Clare Guy ◽  
Michael Dineen ◽  
Fergal Coughlan ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Application Rate ◽  
Dairy Farmers ◽  
Increase Milk Production ◽  
Grazing Systems ◽  
Fertiliser Application ◽  
Grazing Dairy Cows

Grazed grass is considered the cheapest feed available for dairy cows in temperate regions, and to maximise profits, dairy farmers must utilise this high-quality feed where possible. Recent research has reported that including white clover (Trifolium repens L.) in grass swards can have a positive effect on milk production. The aim of the present study was to quantify the effect of tetraploid and diploid perennial ryegrass (Lolium perenne L.; PRG) swards sown with and without white clover on the milk production of grazing dairy cows. Four grazing treatments were used for the study; tetraploid-only PRG swards, diploid-only PRG swards, tetraploid PRG with white clover swards and diploid PRG with white clover swards. Thirty cows were assigned to each treatment and swards were rotationally grazed at a stocking rate of 2.75 cows/ha and a nitrogen-fertiliser application rate of 250 kg/ha annually. There was no significant effect of ploidy on milk production. Over the present 4-year study, cows grazing the PRG–white clover treatments had greater milk yields (+597 kg/cow.year) and milk-solid yield (+48 kg/cow.year) than cows grazing the PRG-only treatments. This significant increase in milk production suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production of grazing dairy cows.

Rumen gases and bloat in grazing dairy cows

1997 ◽  
Vol 129 (4) ◽  
pp. 459-469 ◽  
Author(s):  
P. J. MOATE ◽  
T. CLARKE ◽  
L. H. DAVIS ◽  
R. H. LABY
Keyword(s):  
Carbon Dioxide ◽  
Dairy Cows ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Tracer Technique ◽  
Novel Technique ◽  
Lactating Dairy Cows ◽  
Headspace Gas ◽  
Grazing Dairy Cows ◽  
Kinetics Of

Results are reported from three experiments conducted at the Dairy Research Institute, Ellinbank, Australia during 1992/93 which examined the composition and kinetics of the gas in the rumen headspace of lactating dairy cows grazing white clover/perennial ryegrass pastures. Before grazing, rumen headspace gas was composed of carbon dioxide 65%, methane 31% and nitrogen 4% whereas, after one hour of active grazing, the headspace gas was composed of carbon dioxide 76%, methane 22% and nitrogen 2%. The composition of headspace gas was not affected by antibloat capsules (which release 250 mg/day of monensin). The headspace gas from bloated cows contained slightly less (P<0·01) carbon dioxide and slightly more nitrogen than that from non-bloated cows.A novel technique which employs ethane as a tracer to measure rumen headspace volume and the kinetics of the rumen headspace gases is described. The tracer technique was used in two experiments in which the influence of grazing, antibloat capsules and bloat on the rumen headspace volume and the kinetics of the headspace gases were examined. It is concluded that our ethane tracer technique provides a simple and inexpensive way to estimate methane production by grazing ruminants.

Effects of initial sowing rate and subsequent grazing management on the growth and clover content of irrigated white clover - perennial ryegrass swards in northern Victoria

2005 ◽  
Vol 45 (12) ◽  
pp. 1595 ◽  
Author(s):  
K. B. Kelly ◽  
C. R. Stockdale ◽  
W. K. Mason
Keyword(s):  
Dairy Cows ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Crude Protein ◽  
Net Photosynthesis ◽  
Grazing Management ◽  
First Year ◽  
General Decline ◽  
Clover Content ◽  
Pure White

Two experiments were conducted over 3 years. One was of factorial design involving 2 sowing rates of white clover (Trifolium repens L. cv. Haifa; sown at 8 or 3 kg/ha) and perennial ryegrass (Lolium perenne L. cv. Grasslands Nui; sown at 5 or 15 kg/ha) grazed by dairy cows at 2 frequencies [frequent (2–3 weeks in spring/autumn) and infrequent (4–6 weeks in spring/autumn)] and 2 intensities [hard (residual rising plate meter heights of less than 4 cm) and lax (residual rising plate meter heights of more than 5 cm)]; and the second was a regression design involving 5 sowing rates of white clover and ryegrass ranging from pure clover to pure ryegrass (sown at 10/0 through to 0/20 kg/ha), all grazed frequently and at a hard intensity. The hypotheses tested were that (1) pure white clover swards would be at least as productive as those that contained ryegrass, and (2) more frequent grazing would result in greater quantities of DM removed, while hard grazing would maintain a higher clover content. In general, the hypotheses were confirmed. Over the 3 years of the experiments, pure white clover swards were at least as productive as mixed swards in a situation where no nitrogen fertiliser was applied. In the first year, the amount of DM removed declined (P<0.05) as the ryegrass sowing rate increased, but by year 3, the pure clover treatment out-yielded the other treatments. Except for the first year, frequent grazing resulted in more (P<0.05) DM removed than did infrequent grazing. Frequently grazed swards also had higher daily net photosynthesis after grazing than did the swards in infrequently grazed treatments, and achieved maximum levels of photosynthesis more quickly. There was no difference in photosynthesis rate, despite significant differences in clover content, between sowing rate treatments, regardless of grazing management. Initial sowing rate had a large effect on clover content in year 1, but by year 3, most of this had disappeared as clover contents rapidly converged. Frequency of grazing had its greatest effect on clover content in year 1, with infrequent grazing resulting (P<0.05) in the greatest clover contents. Grazing intensity was an important determinant of clover content in years 2 and 3, where hard grazing resulted (P<0.05) in higher clover content. Digestibility of the herbage on offer ranged from 65 to 80%, and crude protein concentrations varied from 12 to 26%. In general, frequent grazing resulted in a digestibility of 2–4 percentage units higher than infrequent grazing, with hard grazing also tending to increase digestibility. Hard grazed treatments always had high crude protein concentrations in the herbage present before grazing, and there was a slightly higher concentration in frequently grazed herbage compared with herbage that was grazed less frequently. The white clover–perennial ryegrass swards generally responded best to a combination of frequent and hard grazing. However, neither white clover nor perennial ryegrass appears to be well adapted to the combination of soils, climate, irrigation and grazing by dairy cows that occurs in the northern irrigation region of Victoria, as evidenced by a rapid influx of weeds and the general decline in productivity over the duration of the experiment.

Synchronization of ingestive behaviour by grazing dairy cows

1995 ◽  
Vol 60 (1) ◽  
pp. 25-30 ◽  
Author(s):  
A. J. Rook ◽  
C. A. Huckle
Keyword(s):  
Dairy Cows ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Kappa Statistic ◽  
Lactating Dairy Cows ◽  
Random Expectation ◽  
Grazing Dairy Cows ◽  
Ingestive Behaviour

AbstractThe synchronization of eating, ruminating and idling activity by lactating dairy cows grazing a perennial ryegrass-white clover sward was studied. Synchronization was defined as the number of pairs of cows engaged in a particular activity as a proportion of the total possible number of pairs and was compared with random expectation using a kappa statistic. All three activities were significantly more synchronized than random expectation. This suggests that wherever possible individual cows should not be treated as replicates in grazing experiments.

Levels of pasture substitution when concentrates are fed to grazing dairy cows in northern Victoria

2000 ◽  
Vol 40 (7) ◽  
pp. 913 ◽  
Author(s):  
C. R. Stockdale
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Body Condition ◽  
Background Information ◽  
Feeding Strategies ◽  
Paspalum Dilatatum ◽  
Regression Relationship ◽  
Key Variables ◽  
Grazing Dairy Cows ◽  
Marginal Returns

This paper aims to provide information for farmers and their advisers to predict levels of substitution that might be occurring under various feeding conditions in northern Victoria. The approach taken involved compiling data from research conducted in northern Victoria and subjecting these to multiple regression analysis to define the key variables affecting substitution and marginal responses in milk production when concentrates are fed. A significant relationship was obtained between level of substitution (kg DM reduction in pasture intake/kg DM of concentrates eaten) and unsupplemented pasture intake (PI, kg DM/100 kg liveweight) when concentrates are fed. The regression relationship also included species composition of the sward being grazed (species: +1 grass, 0 clover), season of the year (season: +1 spring, 0 summer, –1 autumn) and concentrate intake (kg DM/cow.day). The equation is: Substitution = –0.34 + 0.16 ( 0.035) PI + 0.16 ( 0.053) species + 0.11 ( 0.024) season+ 0.03 ( 0.014) concentrate intake [100R 2 = 50.9 (P<0.01); r.s.d. = 0.14; CV = 37.7%]. Substitution increased by 0.16 kg DM/kg DM for each increment of pasture intake. At any pasture intake, grass-dominant pastures, regardless of whether the grass was perennial ryegrass (Lolium perenne) or paspalum (Paspalum dilatatum), resulted in 0.16 kg DM/kg DM more substitution than white clover (Trifolium repens)-dominant pastures. In addition, substitution was 0.11 kg DM/kg DM higher in spring than in summer, and 0.11 kg DM/kg DM higher in summer than in autumn. Finally, substitution increased by 0.03 kg DM/kg DM for each additional kg DM of concentrates offered. Marginal returns in milk production (MR, kg extra milk/kg DM of concentrates eaten) were negatively related to substitution according to the following regression equation: MR = 2.62 – 0.80 ( 0.216) substitution – 0.28 ( 0.084) season – 0.34 ( 0.086) body condition[100R2 = 62.9 (P<0.01); r.s.d. = 0.23; CV = 29.6%]. Marginal responses were 0.28 kg/kg DM lower in spring than in summer and autumn (season: +1 spring, 0 summer–autumn), and each unit improvement in body condition reduced expected marginal returns by 0.34 kg/kg DM. These relationships, together with those developed to aid estimates of unsupplemented pasture intake, can be used as background information in decision support systems to help farmers and their advisers make more informed decisions about feeding strategies when supplements are fed than has hitherto been possible.duct

scholarly journals Identification of Genomic Regions Associated with Concentrations of Milk Fat, Protein, Urea and Efficiency of Crude Protein Utilization in Grazing Dairy Cows

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 456
Author(s):  
Hewa Bahithige Pavithra Chathurangi Ariyarathne ◽  
Martin Correa-Luna ◽  
Hugh Thomas Blair ◽  
Dorian John Garrick ◽  
Nicolas Lopez-Villalobos
Keyword(s):  
Gene Ontology ◽  
New Zealand ◽  
Dairy Cows ◽  
Candidate Genes ◽  
Milk Fat ◽  
Crude Protein ◽  
Single Locus ◽  
Protein Utilization ◽  
Grazing Dairy Cows ◽  
Genomic Regions

The objective of this study was to identify genomic regions associated with milk fat percentage (FP), crude protein percentage (CPP), urea concentration (MU) and efficiency of crude protein utilization (ECPU: ratio between crude protein yield in milk and dietary crude protein intake) using grazing, mixed-breed, dairy cows in New Zealand. Phenotypes from 634 Holstein Friesian, Jersey or crossbred cows were obtained from two herds at Massey University. A subset of 490 of these cows was genotyped using Bovine Illumina 50K SNP-chips. Two genome-wise association approaches were used, a single-locus model fitted to data from 490 cows and a single-step Bayes C model fitted to data from all 634 cows. The single-locus analysis was performed with the Efficient Mixed-Model Association eXpedited model as implemented in the SVS package. Single nucleotide polymorphisms (SNPs) with genome-wide association p-values ≤ 1.11 × 10−6 were considered as putative quantitative trait loci (QTL). The Bayes C analysis was performed with the JWAS package and 1-Mb genomic windows containing SNPs that explained > 0.37% of the genetic variance were considered as putative QTL. Candidate genes within 100 kb from the identified SNPs in single-locus GWAS or the 1-Mb windows were identified using gene ontology, as implemented in the Ensembl Genome Browser. The genes detected in association with FP (MGST1, DGAT1, CEBPD, SLC52A2, GPAT4, and ACOX3) and CPP (DGAT1, CSN1S1, GOSR2, HERC6, and IGF1R) were identified as candidates. Gene ontology revealed six novel candidate genes (GMDS, E2F7, SIAH1, SLC24A4, LGMN, and ASS1) significantly associated with MU whose functions were in protein catabolism, urea cycle, ion transportation and N excretion. One novel candidate gene was identified in association with ECPU (MAP3K1) that is involved in post-transcriptional modification of proteins. The findings should be validated using a larger population of New Zealand grazing dairy cows.

Supplementation of grazing dairy cows with a brewers grains/treated straw mixture

1990 ◽  
Vol 1990 ◽  
pp. 46-46 ◽  
Author(s):  
J.D. Leaver ◽  
R.C. Campling
Keyword(s):  
Dairy Cows ◽  
Crude Protein ◽  
Dry Matter ◽  
Barley Straw ◽  
Severe Drought ◽  
Grass Silage ◽  
Metabolisable Energy ◽  
Grazing Dairy Cows ◽  
Similar Cost ◽  
Friesian Cows

Supplementary feeding of grazing dairy cows is often uneconomic, and whilst supplementation with silage (buffer feeding) can be worthwhile, this often leads to a depletion of winter forage stores. In this study, a mixture of brewers grains and treated straw was used as a supplement. Offered as a 1:1 mixture in the dry matter (DM), it is a purchased substitute for grass silage, having a similar cost, and similar metabolisable energy (ME) and crude protein (CP) contents. The high seasonality adjustments to milk price in mid-late season make supplementation potentially worthwhile.Experiments were carried out from April to September in 1988 and 1989, which had moderate and very low rainfall respectively. Each year 20 British Friesian cows which calved December to March (1988 experiment) and February-April (1989) were allocated at random to either treatment B or C. In B, the cows were offered a 1:1 mixture (DM basis) of brewers grains and NaOH treated chopped barley straw for 60 minutes after morning milking. In C, the cows received no supplement. Both groups were fed 1.0 kg/day of concentrates in the milking parlour. Due to the severe drought in 1989, concentrate feeding was increased to 5.0 kg/day for all cows during the last 4 weeks of the experiment. Also, urea-treated whole crop wheat was fed at a level of 2.5 kg DM/day during the last 7 days.

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