scholarly journals Effects of particle size and dry matter content of a total mixed ration on intraruminal equilibration and net portal flux of volatile fatty acids in lactating dairy cows

2010 ◽  
Vol 93 (9) ◽  
pp. 4223-4238 ◽  
Author(s):  
A.C. Storm ◽  
N.B. Kristensen
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.


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.


1997 ◽  
Vol 1997 ◽  
pp. 197-197
Author(s):  
R. Sanderson ◽  
S.J. Lister ◽  
A. Sargeant ◽  
M.S. Dhanoa

The objectives of this study were a) to examine the effect of particle size and silage dry matter (DM) content on the rate and pattern of fermentation of fresh silages in vitro as an aid to modelling the in vivo situation and b) to compare the rate and pattern of fermentation of fresh silage samples with those obtained for freeze-dried material.


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.


1993 ◽  
Vol 69 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Jan Dijkstra ◽  
Huug Boer ◽  
Jaap Van Bruchem ◽  
Marianne Bruining ◽  
Seerp Tamminga

The effect of rumen liquid volume, pH and concentration of volatile fatty acids (VFA) on the rates of absorption of acetic, propionic and butyric acids from the rumen was examined in lactating dairy cows. Experimental solutions introduced into the emptied, washed rumen comprised two different volumes (10 or 30 1), four levels of pH (4.5, 5.4, 6.3, 7.2) and three levels of individual VFA concentrations (20, 50 or 100 mM-acetic, propionic or butyric acid). All solutions contained a total of 170 mM-VFA and an osmotic value of 400 mOsmol/l. Absorption rates were calculated from the disappearance of VFA from the rumen corrected for passage with liquid phase to the omasum. An increase in initial fluid pH caused a reduction in fractional absorption rates of propionic and butyric acids. Increasing the initial pH from 4.5 to 7.2 reduced fractional absorption rates of acetic, propionic and butyric acids from 0.35, 0.67 and 0.85 to 0.21, 0.35 and 0.28/h respectively. The fractional absorption rates of all VFA were reduced (P < 0.05) by an increase in initial rumen volume. The fractional absorption rate of acetic acid was lower (P < 0.05) at an initial concentration of 20 mM than of 50 mM. The fractional absorption rate of propionic acid tended (P < 0.10) to decrease as the level of concentration increased while fractional absorption rate of butyric acid was not affected by butyric acid concentration. These results indicate that relative concentrations of VFA in rumen fluid might not represent relative production rates and that attempts to estimate individual VFA production from substrate digestion must take account of pH and VFA concentration.


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.


2021 ◽  
Author(s):  
Maghsoud Besharati ◽  
Valiollah Palangi ◽  
Zabihollah Nemati ◽  
Rashid Safari ◽  
Abdelfattah Z. M. Salem

Abstract The purpose of this study was to investigate the effect of adding various levels of waste sour lemon pomace to lucerne on the properties and ruminal gas production of silage. Levels of 0 (Control), 25 (L1), 50 (L2), 75 (L3), and 100 (L4) % lemon pomace were replaced by lucerne for silage preparation and silenced for 60 days. The experiment was conducted in a completely randomized design with three replications (3 silos per treatment). After opening the silos, pH and dry matter were measured immediately, and the dried samples were kept at -20 until further tests. The silage pH decreased with the addition of lemon pomace compared to the control (p < 0.05). Total silage volatile fatty acids and dry matter content increased with adding lemon pomace. The results of gas production also showed that lemon pomace increased the in vitro gas production volume. Adding lemon pomace to lucerne silage due to the high pectin content in these agricultural wastes caused a rapid decrease of silage pH and an acidic environment. It prevented the growth of non-beneficial bacterial species. The obtained data showed that waste sour lemon has a good potential to use as a livestock feedstuff that can be useful in reducing the cost of ruminant production and preventing environmental pollution.


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