Evaluation of techniques for estimating the yield of irrigated pastures intensively grazed by dairy cows. 2. The rising plate meter

1984 ◽  
Vol 24 (126) ◽  
pp. 305 ◽  
Author(s):  
CR Stockdale

A semi-automatic rising plate meter, the Ellinbank Pasture Meter (EPM) was used to estimate herbage yields of the three most common types of irrigated pasture intensively grazed by dairy cows in northern Victoria. While there were only small differences in precision between the pasture types, yields of pre-grazed pastures were measured more precisely than yields of post-grazed pastures. The EPM also estimated pre-grazing yield more precisely than a visual assessment technique, while the two techniques were similar for estimating post-grazed herbage. A number of factors, including dry matter content of the herbage, botanical composition, season, and lodging due to trampling were shown to influence pre- and post-grazing regressions. It was concluded that pooled regressions were therefore unsuitable for research purposes unless the pooling was for a relatively short period only. Pre- and post-grazing data can be pooled for periods of up to two months to allow the estimation of pasture growth rates at various points of time between grazings. An alternative method of obtaining yield estimates has been proposed in which it is not necessary to develop a regression. This method relies on cutting quadrats in each plot that are representative of the yield and composition of the plot. While this method can circumvent some of the problems associated with the factors that influence the yield-height relationship, severe lodging due to trampling of the sward may preclude the use of the EPM regardless of method.

1970 ◽  
Vol 74 (1) ◽  
pp. 11-21 ◽  
Author(s):  
A. J. Mudd

SUMMARYGroups of lactating dairy cows were fed on grass which had received various amounts of nitrogen and potash fertilizers. In the early part of the season not only was the herbage concentration of calcium and phosphorus lower in grass which had received potash fertilizer but in addition the ‘availability’ of the calcium to cows was depressed. Grass which had received large amounts of nitrogen fertilizer had a comparatively low dry-matter content in the autumn. Cows fed such grass were in negative balance for calcium at this time. As expected high dietary potassium gave rise to high excretion of potassium in the urine which in turn was correlated with high excretion of magnesium. These various factors are likely to affect the incidence of metabolic disease.


2008 ◽  
Vol 52 (No. 12) ◽  
pp. 423-429 ◽  
Author(s):  
S. Kinal ◽  
A. Korniewicz ◽  
M. Słupczyńska ◽  
R. Bodarski ◽  
D. Korniewicz ◽  
...  

The object of an experiment was inorganic and organic forms of zinc, copper and manganese applied in mineral mixtures to dairy cows. The experiment was carried out on 90 cows with average milk yield for previous lactation of about 9 500 kg milk. The cows received mineral mixtures containing inorganic or organic forms of zinc, copper and manganese for 6 weeks before calving and during the first three months of lactation. The application of microelements as bioplexes in amounts covering 30% of daily requirements of cows had a positive effect on an increase in colostrum dry matter content from 20.9 to 23.35% as well as on the concentration of protein and fat, and the level of minerals – calcium, phosphorus, magnesium, zinc and copper. In cows’ milk in the 2<sup>nd</sup> and 3<sup>rd</sup> month of lactation there were no differences in contents of minerals. However in the blood serum of cows in the 1<sup>st</sup> and 2<sup>nd</sup> month of lactation an increase in calcium concentration from 1.96 to 2.14 g/kg was observed while the content of phosphorus also increased average from 1.76 to 2.22 g/kg in the first trimester of lactation.


1944 ◽  
Vol 34 (1) ◽  
pp. 22-26 ◽  
Author(s):  
K. L. Blaxter

1. An experiment has been conducted with dairy cows to find the effect on milk production of feeding rations with a high dry-matter content—typical war-time rations.2. It was found that where a ration high in dry matter is fed, the cow tends to refuse food, and a statistically significant fall in milk production results. The correlation between the refusal of food, calculated in terms of starch equivalent, and the fall in milk production was 0·959.3. The factors causing this inability of the cow to consume sufficient food to meet her total nutrient requirements have been considered. It has been concluded that dry-matter consumption is not an adequate method of expressing the amount of food a cow will consume, and that the major factor influencing food consumption is the palatability of the individual foods making up the ration.My thanks are due to Dr S. J. Rowland for chemical analysis of the individual foods used in the experiments.


Author(s):  
A Hameleers ◽  
T Bronda ◽  
D J Roberts

Buffer feeding is a widely used strategy to improve DM intakes from dairy cows at grass. A very wide range of products have been used as buffer feeds resulting in a wide range of responses. Less well understood are which factors are important in explaining these responses. In this experiment the buffer feed characteristic “dry matter content” and the animal factor “stage of lactation” were used as variables in order to gain a better understanding of responses to buffer feeding.Forty Friesian cows, of which 20 were spring calving and 20 autumn calving were used in a continuous design experiment lasting 5 weeks from 3 May until 7 June 1993. The animals were allocated to four treatments on basis of milk yield, liveweight and stage of lactation. The treatments were grazing only (C), grazing and a buffer feed at 30% DM (B30), 50% DM (B50) and 80% DM (B80) and for each treatment half the cows were spring calving (S) or autumn calving (A). The grazing consisted of a 8 ha field of predominantly perennial ryegrass which was split into 4 equal paddocks which were grazed on a daily rotational basis.


1968 ◽  
Vol 70 (1) ◽  
pp. 19-27 ◽  
Author(s):  
C. A. Foster ◽  
C. E. Wright

SummeryThree sampling experiments were conducted to examine the effect of sample size and sampling intensity on the precision of dry-matter content and botanical composition estimates of perennial rye-grass-white clover herbage. One of these experiments examined the between-sample variability of these attributes and of dry-matter yield in relation to other sources of experimental error in a small-plot sward trial. The sample sizes examined were 800 g, 400 g, 200 g, 100 g, 50 g and 25 g green weight. In general the accuracy of dry-matter content and botanical composition estimates decreased with decreasing sample size. The between-sample variabilities of 25 g and 50g samples were high in relation to their between-plot variabilities. Single 100 g samples provided reasonably good estimates of these attributes and of dry-matter yield, but single 200 g samples provided a more satisfactory margin for error. Samples larger than 200 g appeared to be unnecessary. When weight-for-weight comparisons of single and duplicate samples were made there appeared to be little advantage in duplicate sampling. A theoretical examination of measurement inaccuracies inherent in the techniques used in small-plot sward trialssuggested that variation in plot length measurements in particular may make an undesirable contribution to the variability of such trials. A procedure for the conduct of small-plot trials is recommended. It is concluded that, where plot size and replication are limited, further improvement in the precision of such trials will not be readily attainable.


1981 ◽  
Vol 61 (3) ◽  
pp. 633-638 ◽  
Author(s):  
P. L. BURGESS ◽  
J. W. G. NICHOLSON ◽  
E. A. GRANT

Two experiments were carried out, using 36 lactating Holstein cows, to determine the effect of three levels (0, 4.5 and 9.0 kg/day) of alfalfa pellets (AP) on the ad libitum consumption of early and late harvested timothy grass silages of different dry matter (DM) content. Cows consumed significantly more wilted than nonwilted silage DM for both the early and late harvested grass, although milk yields were similar for both groups. For the early harvested, wilted and nonwilted silages, feeding AP did not significantly depress silage DM intake until a level of 9.0 kg/day was reached. Total ration DM intake increased significantly with each increment of AP. With the late harvested silages, AP at the 9.0 kg/day level reduced nonwilted silage DM intake while with the wilted silage each increase of AP significantly lowered silage DM intake. Both the 4.5 and 9.0 kg/day of AP increased total DM consumption with the nonwilted silage but 9.0 kg/day of AP was required to significantly increase total DM intake for cows fed the late harvested, wilted silage. Milk yield and milk composition were not changed by the level of AP supplementation or the type of silage fed.


Author(s):  
Юрий Победнов ◽  
Yuri Pobednov ◽  
Антон Мамаев ◽  
Anton Mamaev

Aerobic spoilage in silage and haylage is affected by the intensity of alcoholic fermentation, which causes the amount of nutrient loss of the feed during excavation from the trench. The negative effect is not the alcohol content, as such, which in some cases even helps to improve the aerobic stability of the feed, but the amount of yeast found in the silo and hay at the time of opening the silos, which, in turn, depends on a number of factors. One of these factors is the low sugar-buffer ratio in plants, which should be ≤2.5. Under this condition, there is a slight accumulation of alcohol in the dry matter of the feed, which indicates a weak development of the yeast. The second factor that determines the aerobic stability of the feed and the amount of nutrient loss during storage in air is the dry matter content of plants. When stored in the air of haylage and silage from dried herbs, the loss of dry matter is reduced, reaching a minimum when preparing food from plants with a sugar-buffer ratio of ≤ 2.5. This is especially noticeable in the first 2–3 days of storing feed in the air. Subsequently, the loss of dry matter from aerobic spoilage begins to increase, causing the occurrence of secondary fermentation, which leads to its spoilage of feed. The third factor determining the aerobic stability of a silo is its shelf life under anaerobic conditions, which should not be less than 90 days. This follows from the biological features of the development of yeast, which are the main initiators of aerobic spoilage. However, haylage is predisposed to aerobic spoilage for any shelf life in trenches.


2000 ◽  
Vol 71 (2) ◽  
pp. 349-357 ◽  
Author(s):  
D. L. Romney ◽  
V. Blunn ◽  
R. Sanderson ◽  
J. D. Leaver

AbstractTwelve dairy cows in early lactation were offered low (L; 215 g/kg) or high (H; 449 g/kg) dry matter(DM) content silages, prepared using material from the same sward. In addition, all animals received 9 kg/day, of supplements based on barley (B), sugar-beet pulp (SB) or a 50: 50 mixture of the two (B: SB), in two equal portions at 07:30 and 14:30 h. The six treatments were offered in an incomplete Latin square design. Mean intakes of H (14·4 kg DM per day) were significantly higher than intakes observed for L (10·0 kg DM per day) (P < 0·001). Within silage type, highest intakes were observed for cows receiving the SB supplement (P < 0·01). Higher intakes of H were reflected in higher total milk yield (P < 0·05) as well as fat (P < 0·05) and protein (P < 0·01) yield. Milk protein concentration was greater for animals receiving silage H (P < 0·001), with lower values being observed for animals consuming SB (P < 0·05), within silage type. Time spent eating, duration and number of meals were similar for either silage and the higher intakes of H silage reflected greater intake rates (g DM per min) (P < 0·001) resulting in larger meal sizes (P < 0·001). All chewing indices (time spent eating silage, ruminating and total time chewing per kg DM ingested) were greater for the L silage (P < 0·001). It is concluded that the benefits in forage intake with higher DM grass silages, for high yielding dairy cows, are associated with consequential benefits in milk yield and milk protein content. The most likely explanation for the greater intakes is a faster particle breakdown in the rumen allowing larger meal sizes before animals became constrained. The higher intakes of silage when animals consumed the SB supplement may be due to a slower rate of fermentation of the supplement, which was more closely matched to that of silage. Although not significant there was a tendency for differences in silage intake between animals receiving B compared with SB supplements to be greater for animals receiving the H silage suggesting that supplementation strategies to ensure optimal forage utilization may differ for silages of differing DM content.


1977 ◽  
Vol 25 (3) ◽  
pp. 397-400 ◽  
Author(s):  
M. E. Castle ◽  
W. C. Retter ◽  
J. D. Metcalfe

SUMMARYGrass silage with a dry-matter content of 20·7%, and containing 18·9% crude protein and 67·0% digestible organic matter in the dry matter was self-fed to 20 lactating dairy cows for 18 weeks. In addition, 9 kg of brewers' grains with a dry-matter content of 28·8% was offered to each cow daily. The two supplement treatments were a barley mix and a groundnut cube containing 11·9 and 33·5% crude protein in the dry matter respectively. The barley was given at the rate of 4 kg/10 kg milk, and the groundnut at 1·5 kg/10 kg milk. The mean daily yields of milk were 18·9 and 19·4 kg/cow on the barley and groundnut treatments respectively and did not differ significantly.


1984 ◽  
Vol 24 (126) ◽  
pp. 300 ◽  
Author(s):  
CR Stockdale

A visual assessment technique was evaluated for estimating pre- and post-grazing pasture yields in experiments in which dairy cows rotationally graze irrigated pastures. Visual assessment, when associated with the harvesting of standard quadrats, accounted for 62.3 and 68.4% of the variability in pre- and post-grazing yield, respectively. The mean residual standard deviations associated with the pre- and post-grazing regressions were 490 and 395 kg dry matter/ha and, when the variable yields were taken into account, these represented coefficients of variation of 15.6 and 19.0%, respectively. By using the coefficient of variation as the criterion for precision, pre-grazing regressions were significantly more precise than post-grazing regressions. In practice, visual assessment by a double sampling procedure can be used to estimate pre- and post-grazing yields in dairy cow grazing experiments where herbage intakes and growth rates are required, provided sufficient readings are taken to allow an acceptable level of precision. It is suggested that about ten standards are required to formulate a calibration regression regardless of whether or not the pasture to be assessed has been grazed. Although the double sampling technique may be suitable for research purposes, it has been demonstrated that the completely subjective eye appraisal, often used by farmers and their advisers for feed budgeting, can result in many incorrect assessments. A more objective technique needs to be developed for this purpose.


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