TMR stability improved with additives

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August/november 2018

TMR stability

improved with

additives

Effect of Additives on Aerobic

Stability and Dairy Cow Intake

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Name: James Hoban

Student Number

:

3026428

University

:

Aeres University of Applied Sciences

Program: European Engineer Degree Livestock Production

Thesis coach: Mariska van Asselt

Date and place of publication: January 2019; Dronten

Placement company: SLU, Sweden

Thesis coach: Mariska van Asselt

Date and place of publication: January 2019; Dronten

Placement company: SLU, Sweden

Placement Coach: Bengt-ove Rustas

TMR stability improved with

additives

Effect of Additives on Aerobic Stability and Dairy Cow Intake

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Table of content

Table of content ... 3 Acknowledgment ... 4 Summary ... 5 Introduction ... 6 Grass storage ... 7

Total Mix Ration (TMR) ... 8

Silage additives ... 8

Research Question ... 12

Material and methods ... 13

Brief description of the experiment ... 13

Animals ... 13 Diets ... 15 Data collection... 15 Data analyses... 16 Results ... 18 TMR stability ... 18 Cow performances ... 20 Discussion... 21 Conclusion ... 23 Bibliographie ... 24

Annex 1: silage composition ... 27

Annex 2: Concentrate composition ... 29

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Acknowledgment

As part of my European Engineer Degree course with a Livestock Production option, I had the opportunity to go on a 14 week internship in Sweden at the SLU in Uppsala. During this

placement, I was given the chance to participate in a research study for the dairy feed sector in an aim to evaluate a product given by a private company.

I would like to thank Julia Österberg who had the great kindness to accept me in this establishment as well as Mr Bengt-ove Rusta who helped me during this placement and gave me great guidance on the subject studied.

I would also like to thank Mrs Mariska van Asselt who had great patience to answer all my questions and help me structure my report.

Moreover, would like to thank all the teachers I had in Aeres University who helped me go this far and particularly Mrs Tempert, Jantien the course coordinator who was of great help during all this semester in Dronten.

And at last, I would like to thank my family who gave me this great opportunity to be able to study abroad and was always present to support and encourage me when I needed them.

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Summary

In order to increase feed quality, additive has been used to increase silage storage stability. During feeding time, the silage is exposed to oxygen and a degrading process starts decreasing dry matter and increasing temperature. This rise in temperature makes the silage less appetising to cows, few additives have been used to increase aerobic stability aimed to increase feed intake. An additive containing potassium sorbet, sodium sorbate and propionic acid was tested at the SLU in Uppsala (Sweden). This additive has been added to a grass based total mix ration (TMR) in a first treatment and a control treatment without the additive has been distributed to 20 cows in a changeover design with 3 periods and 2 treatments. The TMR’s have also been stored in a stability chamber and temperature was recorded to estimate the time it took the silage to rise 3 degrees above ambient temperature. Results found that the additive improved the TMR stability during the first 24hrs of creating a TMR (p=0,038) by 20 hours however found a reduce effect of the additive after 24hrs. The cow’s performance was recorded, and results show no increase in food intake, this could be explained by a delay in feeding (24h after TMR created) but then again, a significant crease in water consumption (p=0,008) was detected in the group receiving the additive. This in-crease could be explained by the composition of the additive containing a large amount of sodium sorbet (salts) that stimulates drinking behaviour. Although results showed an increase in milk solids there was no increase in milk production, too few samples were taken to put any reverence on these results. This additive needs further testing to see possible side effects of exposure to large amount of salt over a long period of time but the additive does improve aerobic stability over a short period of time and could be used to further the quality of the TMR over the day.

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Introduction

Farmers are under pressure looking for new ways to optimise their systems, feeding regimes need to maximise production. One way of expressing a feed is by its stability. Additives can be used to increase a feed ration's stability and can therefore lead to a bigger intake of food. It is important that the food is of high quality allowing the animal to express its maximum genetic potential. Feed can amount to 70% of operating costs and 30% of total cost (Réussirlait, 2012)making it important financially to the farmer.

Grazing grass is a natural diet for cattle and has a good balance of nutrients for a cow to live and produce milk. Studies show that grazing is the cheapest way to feed cows with costs around 60€/ ton of dry matter (Guibert, 2018). Grazing may be the least cost method for milk production but production per cow is limited because it has a low energy density ratio. Furthermore, in most regions worldwide grazing is not available all year and can vary in quality and quantity, therefore farmers cut and store grass for these periods. Farmers add other products to increase the energy in the ration, generally grain based such as wheat or barley grain but also by products such as soya or rape and other forages. These products can either be added separately to the main forage by a concentrate distributor or by other means (hand fed or other) requiring extra labour and

investment. With larger herds, farmers mix the concentrates and silage together to save time and reduce microbial upset in the rumen by providing a homogeneous feed, known as the total mix ration or TMR. (Schingoethe & David, 2017).

There are several ways to store grass, the dry way (hay), and the wet way, either silage bales or in silage pits. Microbial activity by lactic bacteria lowers the pH, this prevents all other forms of bacteria developing and degrading the nutritional value of the grass (rotting). Lactic bacteria require specific conditions humidity, oxygen and a low PH, to enable optimum activity, (McDonald , Edward, Greenhalgh, & Morgan, 1995). To improve these conditions additives can be added at harvest time to help lower the pH. These additives added during the ensiling process rarely influence the plant respiration and the subsequent rise in temperature of the silage when reopened for feeding (aerobic stability).

Furthermore, once distributed to the cows the aerated silage heats up and becomes less appetising. Milk production is reduced (Andersson , 1984) because feed intake is directly correlated with milk production (Agricultural research Council, 1980). Farmers therefore make a TMR daily to have a fresh mix to feed their cows, this is costly in time.

Recently new products are being developed to improve TMR stability (reduce heating effect). This could be beneficial for batch making TMR perhaps lasting fresher for several days. Exterior temperature also influences the TMR stability (Ashbell, Weinberg, Hen, & Filya, 2002) (Junga & Travnichek, 2015). During the winter, these additives may allow for batch TMR, and during the summer could improve a TMR stability during the day, keeping the food fresher for longer. This could improve the cows’ feed intake whilst adding flexibility and reducing labour cost.

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Grass storage

To store grass for winter usage, farmers may use different ways depending on the weather conditions. The cheapest way of storing grass is the dry way. Haymaking consists of cutting the grass, drying naturally with the sun's heat, then storing it in barns when the dry matter content reaches 75-85 % (McDonald , Edward, Greenhalgh, & Morgan, 1995). This process can take a long time as it is dependent on extended periods of dry weather.

Bringing in the grass when it is still moist adds flexibility, silage is a way of conserving a crop by the process of fermentation. To ensure a good conservation the primary objective is to achieve

anaerobic conditions by enclosing a finely chopped compacted crop in plastic sheets to prevent air circulating. Once closed, the remaining oxygen is quickly used up by the respiratory enzymes in the plant cells (McDonald , Henderson, & Heron , the biochemistry of silage, 1981). If air does get in, fermented materials become unstable, mainly by the appearance of yeast (McDonald , Henderson, & Heron , the biochemistry of silage, 1981) (Beck, 1978). Yeast consumes lactic acid bacteria causing an increase in pH. When the pH increases, proteolytic bacteria and mould start to degrade the nutrients, the forage decays, producing an unstable and frequently toxic product. (McDonald , Edward, Greenhalgh, & Morgan, 1995) (Alonso, et al., 2013).

The second step is to discourage the development of undesirable microorganisms such as

Clostridia and Enterobacteria, these should be contained when lactic acid bacteria (LAB) develops in enough numbers. LAB is present on the crop in small quantities before ensiling but develops rapidly in anaerobic conditions and consumes soluble carbohydrates (lättemäe, 1997). This bacterium produces mainly lactic acid. This lactic acid results in a drop in pH (see Figure 1). The molecules of these acids can penetrate cell walls and are responsible for the antimicrobial activity (Lindgren, 1991). When the pH falls to around 4.0, a stable phase begins (McDonald , Edward, Greenhalgh, & Morgan, 1995). A little activity can occur during this phase depending on how air tight the silo is (walls and plastic) but should be minimal.

Figure 1, Phase of normal Fermentation (Heinrichs, Ishler, Jones, & Roth, 2004)

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When a silage pit is opened for feeding, air has access to the silo, Enterobacteria and Bacilli immediately start to develop and degrade the silage (lättemäe, 1997). Silage is often used as a base, to which is added other ingredients such as concentrates and minerals, mixing all these ingredients together creates a total mix ration which is distributed to the cows providing a nutritionally balanced feed in a single passage.

Total Mix Ration (TMR)

Total mix rations (TMR) have increased in popularity in European countries since the 1950’s. There are numerous advantages to using TMR feeding, such as improved feeding efficiency. Although the animals tend to have a higher number of feeding sessions, but of smaller quantities, cows tend to be less “picky” with a TMR feeding system resulting in a better overall diet (Ionnis, 2015).

Furthermore, the ration can be closely monitored using scales and technology. The diet is

homogeneous all day and from one day to the next, improving rumen fermentation. This improved rumen function has been shown to result in a higher feed intake, 4% higher compared to a

conventional ration of forage and grain fed separately, (PennStat Extension , 2015). As there is a direct correlation between feed intake and milk production the latter also increases.

TMR has some drawbacks; there is moderate expenditure in mixer and equipment. The technicality of the system needs some experience to operate, mix for too long and the feed become slushy, not enough and it could result in a less effective feed utilisation, it is time consuming to mix every day.

Silage additives

To help the process of fermentation and conservation of forage during ensiling, two main types of additives exist. One group can be characterized as fermentation stimulants, such as inoculant bacteria like lactic acid bacteria (LAB) naturally present in silage, in enzymes like cellulase, hemicellulose and fermentable subtracts like molasses or water. The inoculant additives aim to increase the number of bacteria favourable to fermentation. Lactobacilli, pediococci and

enterococci are bacteria already present in the forage in small quantities, these bacteria help the process of fermentation (Heinrich, Ishler, Jones, & Roth, 2004). Another fermentation stimulant Is molasses. Molasses can be used as food for the bacteria to help their development (Heinrich, Ishler, Jones, & Roth, 2004). Although molasses can be used in poor energy level silage, to improve its overall energy value, a study shows that it does not have any effect on stability, either after 45 days of storage or aerobic stability after reopening the silos (Yuan, et al., 2015). This eliminates the possibility of using molasses in TMR mixes to improve its storage stability because the effect of molasses is only effective at the beginning of the ensiling process.

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The other type of additive is a fermentation inhibitor. These are often chemicals composed of acids like propionic, sorbic, or benzoic acids, etc (Muck, et al., 2018). Before the years 2000,

homofermentation bacteria were used. Since then, heteroferments like Lactobacillus and Buchneri are used. Studies of these types of additive on the parameters of silage making show significant effect on reducing the loss of nutrients due to ensiling by providing a faster decrease in pH (Dunière , Chaucheyras-Durand , Chevallier, Sindou , & Thévenot-Sergentet , 2013)(see Table 1 for further details). As we can see, the use of heteroferments also increases the number of acetic acids, because these bacteria, after fermentation, can transform lactic acid into acetic acid. The acetic acid is a good way of improving aerobic stability by preventing the development of undesirable fermentations (Muck, et al., 2018) (Dunière , Chaucheyras-Durand , Chevallier, Sindou , &

Thévenot-Sergentet , 2013). These additives are designed to help the process of fermentation and lower the pH rapidly, not to keep the pH low and therefore they do not influence the stability of the silage once exposed to air.

Enzymes are used to degrade cellulose or hemicellulose in silage to improve digestibility, the soluble sugar produced can also feed the bacteria favourable to desirable fermentation, boosting the production of LAB and therefore decreasing pH (Hoffman & Muck, 1999). Studies (Liu, Li, T Desta, Zhang, & Shao, 2016) did not show significant benefits in using these enzymes on fermentation quality, nutritive value and digestibility in vitro of TMR mixes containing rape straw because the moisture levels were not high enough to allow the development of the LAB. Other Studies from Harrison, (Harrison, 1996)also detected little improvement on milk production but found improved fermentation and dry matter intake. Studies (Kleinschmit & L. Kung, 2006) show the benefit of using Lactobacillus buchneri on maize and grass silage to improve its aerobic stability by 206 hour at a concentration rate of: L. buchneri at ≤100,000 cfu/g, in addition, traces of yeasts were nearly undetectable. It is rare for these silage preservatives to be double acting, both helping the ensiling process and improving the aerobic stability once opened. Specialized formulas have been created to target the aerobic stability of the silage, these are called Fermentation inhibitors.

Table 1, Effect of an additive on silage (Knicky & Sporndly , 2015)

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The aerobic fermentation is inevitable at the beginning of the ensiling process but is quickly stopped using the right methods of ensiling and the possible use of additives. When the silo needs to be opened, to be fed to the livestock, the silage is exposed to air, allowing yeast, fungi and moulds to grow. For this reason, companies have started to develop fermentation inhibitors to slow down this effect and create a better aerobic stability. The additives are generally chemical based containing propionic acids, salt like sodium nitrate, sodium benzoate and potassium sodium. These ingredients reduce nutrient loss and therefore dry matter content (Figure 2).

Propionic acid is a short chain fatty acid that produces a large amount of antimycotic activity (prohibitor of fungi) (Kung, et al., 1998). This slows down the development of fungi and thus, improves the silage stability. Multiple studies show the benefit of propionic acid either in use on its own (Knicky & Spörndly, 2015), or in combination with other products like LAB (Chen, et al., 2016) showing a better resistance to heating (lower max temperature). This heating can harm the proteins in the crop. It also shows that silage treated with propionic acid has better aerobic stability.

A good indication of this is the amount of days it takes for the silage to rise 3 degrees above ambient temperature. The treatments receiving the propionic acid took twice as long to reach a 3-degree rise (Borreani, Holmes, Muck, Tabacco, & Schmidt, 2018) (Chen, et al., 2016). High

concentration uses of propionic acid (1 to 3 % of DM) often allowed for greater intake, Kung study (Kung, et al., 1998)used a much lower concentration (0,1 to 0,2 % of DM) of buffered propionic acid in a total mix ration (maize silage based) and found very little effect on intake. Their hypothesis suggests a combination of low amounts of active ingredients and the use of a low amount of buffered propionic acid is the cause. (Kung, et al., 1998). But the results of TMR stability suggested a positive effect of propionic acid improving aerobic stability with a better heating resistance. Propionic acid is a proven product to improve storage stability and aerobic stability but is costly and dangerous to use (corrosive) other products such as Salt can also be used to improve storage

stability.

Sodium Sorbate (NaC6H7O2) Sodium Sorbate is an antimicrobial agent, often used as a preservative in food and drinks to prevent the growth of mould, yeast and fungi. Sodium Benzoate is a similar product already used in silage preservation and proven by studies to increase the DM and a lower concentration of Ethanol on maize silage ( Kleinschmit, Schmidt, & Kung, 2015) as shown in the table 2. Potassium sorbate is a substance that reduces production of ethanol in silage ( Sasha ,

Figure 2 Weight loss during storage of silage treated with an additive mixture of sodium benzoate, potassium sorbate, and sodium nitrite and of a untreated control (Knicky & Sporndly , 2015)

Figure 2 Weight loss during storage of silage treated with an additive mixture of sodium benzoate, potassium sorbate, and sodium nitrite and of a untreated control (Knicky & Sporndly , 2015)

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Roberto , Liming kung, Rotz, & Mitloehner, 2014) and therefore increase the DM. A study from Silva (Silva, Smith, Barnard, & Jr., 2015)has been carried out to evaluate the effect of mixing these

compounds together (potassium sorbate, sodium Benzoate and sodium nitrate) on maize silage storage and aerobic stability. They found a significant increase in aerobic stability in the maize silage containing the additive mix, with a lower amount of lactate assimilating yeasts. Suggesting that the potassium sorbate, sodium Benzoate and sodium nitrate prevents the activity of the aerobic deterioration.

When lactic acid is degraded, the pH rises allowing for more types of microorganisms to develop (Borreani, Dolci, Tabacco, & Cocolin., 2013) (Knicky & Spörndly, 2015)in a short communication found the same effects when using a similar product on several types of grass forage reinforcing the effectiveness of sodium nitrite, sodium benzoate, and potassium sorbate on aerobic stability in silage.

Although multiple studies show the individual advantages of each fermentation inhibitor, few studies show the effect of a combination of these additives. Furthermore, the studies are carried out on silage alone and not a TMR. With TMR mixing, the pH of the initial silage is modified because all the ingredients do not have the same levels of pH or Stability. A recent study at the SLU in Sweden tested an additive containing sodium sorbate potassium sorbate and propionic acid in silage alone, (concentrates were given separately). It found an increase in stability and a lower maximum temperature than the control treatment. The study also focused its use on dairy cows and more precisely on their daily feed intake. It found a significant reduction in intake with this additive suggesting that the cows did not like the taste of the silage containing the additive (Guiquel , 2018). Therefore, further study is needed on the effect of this additive with sodium sorbate, potassium sorbate, Glycerolpropionater and propionic acid on a total mix ration stability, the possible effect on cow’s intake and therefore the impact on milk production.

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Research Question

The objective of the study is to determine the effect of this additive on TMR mixing, the knowledge obtained may be used by farmers to reorganise their feeding strategy allowing them to make a large amount of TMR a few times a week rather than every day. This may add flexibility to a farmer’s work schedule without deteriorating the quality of the feed. The main research question is:

To what extend additive containing Sodium sorbate, Propionic acid, Glycerolpropionater and potassium Sorbate influences dairy cows’ feed intake due to improved TMR stability

To help explain the main question, sub questions are edited to split the work and make a clearer picture:

Sub question one: To what extent does the additive influence the TMR stability over the course of several days?

Sub question two: To what extent is dairy cows’ intake modified by using the additive in the TMR ration?

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Material and methods

Brief description of the experiment

To determine the possible effect of the additive on TMR stability and cows’ feed intake, an

experiment has been laid out in a change-over design with 2 treatments, a control treatment and a treatment containing the additive, and 3 experimental periods of 3 weeks each (table 3). Total trial time was therefore 10 weeks, including one week's adjustment. The trial ran from week 31 to week 40, early August until beginning of October 2018. The two feed mixes were prepared in a TMR mixer the bins were emptied and cleaned every day. Feed intake and eating behaviour have been recorded continuously throughout the experiment. Milk production was recorded daily, and milk sampling took place during 2 days in the last week of each period (data collecting week).

Table 3, Description of experiment planning

Week Date Task

31 30/07/18 05/08/18 Adjustment 32 06/08/18 12/08/18 Start of experiment 33 13/08/18 19/08/18 34 20/08/18 26/08/18 Collection 35 27/08/18 02/09/18 36 03/09/18 09/09/18 37 10/09/18 16/09/18 Collection 38 17/09/18 23/09/18 39 24/09/18 30/09/18 40 01/10/18 07/10/18 Collection Animals

The experiment took place at the Swedish Livestock Research Centre, Lövsta, Uppsala. A group of 20 Holstein cows have been used in this experiment. The cows were mid lactating (70 – 150 DIM). 1st_{lactating cows are still growing so the intake might vary, to eliminate this factor there were not}

any 1st_{lactation cows in this trial. The cows were mixed within a group of 60 cows in a free stall}

barn. The cows had access to bins on weighing scales with a preselecting gate to monitor intake and eating behaviour. Each group of 10 cows had access to 4 bins containing their diets. The 60 cows were milked in an automatic milking system (VMS, DeLaval, Tumba, Sweden). The change-over design means that the cow’s diet changed in each of the 3 experimental periods (table 4). The cows were randomly assigned to one of the treatment sequences shown in the table below. The

changeover design is constructed to reduce animal variation by testing each treatment on all the cows. The third treatment period allowed identification and adjustments for carry over effects.

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Table 4: cow’s treatment per period Cow Group 06/08/2018-26/08/2018 27/08/2018-16/09/2018 17/09/2018-7/10/2018

treatment treatment Treatment

48 4 Tillsat Control Control

161 4 Tillsat Control Control

312 3 Control Control Tillsat

367 3 Control Tillsat Tillsat

384 4 Tillsat Tillsat Control

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Diets

The total mix ration (TMR) was identical and based on the Silage DM. a further 2 kg of Komplett Fiber 170 is given through the robot. The diet consisted of grass silage, concentrate in the form of a pelleted compound feed (see annex 1 and 2 for full composition) and mineral feed as a bases for the two. A sodium sorbate bass additive, in a powder form was added to one ration (see formula in table 5). The treatment one (name of treatment= tilsat) contained the additive, treatment two (name of treatment=control) did not have this additive. The additive used is ProMyr TMR from Perstorp, the feed was mixed the previous day around 11 am and stored on the floor in the free trial area located near the TMR mixer. The bins were cleaned every morning before serving half of the daily diet around 8am, the other half of TMR was given in the evening around 5pm. The study aimed to have 5% left over in the bins to ensure

unlimited access to feed. The two feed mixes were prepared in a TMR mixer. Feed intake and eating behaviour was recorded continuously throughout the experiment with a Biocontrol system. The additive used is a mix of several products but has a main ingredient being Sodium Sorbate, other elements like potassium Sorbate, propionic acid and Glycerolpropionater are present in smaller quantities (table 7 for more detail)

Data collection

Throughout the whole trial, certain data was recorded continuously such as milk production using the delaval Robot (VMS, DeLaval, Tumba, Sweden), feed and water intake were registered

continuously with herd manager Biocontrol. Biocontrol measures every time a cow eats or drinks, it records how much and for how long the cow has eaten. Silage samples were collected at the end of each 3 weeks of treatment for 6 days. Only the results of the third week of each period was

analysed but a wider time span was looked at to clarify certain results. During the collection week, milk samples were taken over two days (Wednesday and Thursday) and were later analysed with a CombiScope FTIR at the SLU. 7 samples of approximately 1 kg each have been taken from the TMR’s and silage every day of the collection weeks (see table 6 for example) to determine the effect of the additive on TMR stability. One sample from raw silage taken from the pit, 1 sample from the freshly made TMR of that day destined to be fed the next day. Samples were also taken from the feed just before being fed to the cows in the morning (1-day old TMR) and from the left overs of that morning, one third of these samples are doubled to be frozen. From these samples, multiple tests were conducted:

- The dry matter (DM) was measured from 200g of the silage sample and the control fresh mix (60°c 24h) Element % in Powder Sodium Sorbate 75-85 potassium Sorbate 10-15 Silica, amorphous 5-10 propionic acid 3-7 Glycerolpropionater 1-4

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- The pH of each sample was tested. 60g of silage or TMR was placed in a plastic bag the same amount of Milli-Q water is added and was left to soak overnight. The next day these samples were pressed using hydraulic press to extract the juice. Then, using a pH meter, the pH was measured. pH is the measurement of acidity or base in aqueous solution (or better, activity of H⁺ more precisely Hydronium Ions H₃O⁺ or OH⁻).

- To do a stability analyse, a sample of approximately 300g of TMR and 360g of silage (based on DM) were placed in tubes with a thermometer in the middle of each tube. These tubes were placed in a controlled environment where humidity and temperature are constant (20°C and 75% humidity) and were left there for 7.5 days. Temperature was logged automatically every two hours.

- When these samples had spent 7,5 days in the stability monitor, the samples were placed in plastic bags and an equal amount of Milli-Q water added. These were then left to marinate over night in the fridge. The juice was extracted the next day and later analysed for pH. An eating behaviour study had been carried out on the same cows and diets, some data from that study may also have been used in this study to examine the cow’s behaviour in relation to the additive.

Table 6: Sampling example of silage and TMR bag

number

sample date of collection pH before

pH after

101 Silage 20-août 4,05 8,37

102 fresh mix Tilsat 20-août 4,28 8,36

103 fresh mix Control 20-août 4,3 8,66

104 TMR 1-day old Tilsat 20-août 4,37 8,26

105 TMR 1-day old Control

20-août 4,29 8,66

106 Left overs Tilsat 20-août 4,43 8,46

107 Left overs Control 20-août 4,71 8,22

Data analyses

To determine the effect of the additive multiple tests were used. As the cows were milked on a AMS, it is difficult to know the daily milk yield because of variation in milking times and frequencies. The data was sorted on the bases of Nielsen’s work about calculation of milk yield for dairy cows in an AMS (Nielsen , Pettersson , Svennersten-Sjaunja, & Norellt, 2010). The same principle was applied to the concentrate given through the Robot. Data extracted from the Lövsta Experimental Farm arrived in a Bloc note format. This data was sorted using Excel 2016. Once it was sorted, Minitab was used to analyse the data using either ANOVA in a first instance then if needed a tukey test (T-Test) was used.

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To determine the extent of the additive effect on TMR stability, we have compared the aerobic stability results (days until +3 degree rise in temperature) using ANOVA, furthermore t-test analyse was conducted to evaluate the difference in pH before and after the stability trial. To evaluate the ingestion rate, an ANOVA test was performed comparing the overall intake of feed (in kg), with the treatment and treatment period. Other parameters such as milk production (in kg/cow/day) and milk quality, maximum silage temperature (in °c) and water intake (in kg) was described and may feature in the discussion part.

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Results

This study has tried to determine the effect of an additive containing propionic acid, sodium

sulphate and potassium sorbate. In the first section the additives effect on TMR stability is analysed and secondly the cow’s reaction to this additive by their feed intake.

TMR stability

To evaluate the effect of the additive on feed quality samples were taken from the control treatment and treated treatment at Lövsta experimental station in Uppsala, Sweden. Feed intake was also monitored during the trial. The samples were analysed to determine pH, max

temperature and time taken for a three degree increase in temperature in relation to ambient temperature.

In total, 4 complete cycles were recorded for each of the 3 periods totalling 12 cycles for each group. One cycle consisted of silage, fresh mix TMR, 1-day old TMR and left over TMR from the same original silage. Figure 3 shows a broad overview of the time taken to reach a 3 degree rise for each stage during all the cycles. In a first experiment the study analysed the difference between Silage and Fresh TMR. Observation shows that silage (47,5h) had a lower stability than the treated TMR, pure silage seems to have a better stability than the control treatment Total mix ration(38,2). These results are not significant because of a low amount of data (12 Treated, 12 control and 12 silage).

In the second part, the study left out the pure silage and concentrated the research on the TMR’s. In a mean comparison the study compared the different stages of the TMR (fresh- 1 day old- 2 day old (left overs)) with the two different treatments to see whether the additive extended the stability of the TMR over a period of time.

A statistical model has been created to compare the different samples, the three different time periods and the carry over effect (some cows changed treatment every three weeks). Results for “hours to 3°c rise” the model shows that the period (p=0.0081) influenced the additive, and the treatment (p=0,0229) showed a significant difference. The period difference means that there were variances within the same treatments over the 3 periods and that there were variances between the 2 different treatments. The fresh TMR’s present a significative difference (p=0,038) indicating that the additive has had a positive effect on increasing the stability for fresh mix. Fresh TMR containing the additive took 20 hours longer to reach a 3 degree rise in temperature than the control treatment. Silage 47,5h treatment additive control fresh mixTMR 58,2h 38,2

Figure 3, mean hour to 3 degree rise in silage and fresh mix for treatment and control

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In this statistical analysis, fresh TMR was the only variable which presented a significant difference between treatments. One day (p=0,132) and left overs (p=0,933) did not show any difference be-tween treatments, the additive does not have any effect on 3 degree rise after 24hours in the TMR. It was also interesting to look at the effect of time in relation to the treatment. The control treatment showed a significant difference between fresh mix and 2-day old TMR(p=0,001) and there is a ten-dency between fresh mix/1 day and 1 day/left over indicating a potential correlation of increasing feed instability as the TMR ages. The treatment containing the additive was non-significant between fresh, one day and leftovers showing that the additive reduced the effect of time on the 3-degree rise. The graph 4 summarises these results in a visual effect, it presents the mean value of all the sam-ples from Fresh mix, 1 day old and 2 day old (left overs), p-values comparing the two different treatments as well as comparisons between different time periods within the same treatment. As said previously, the mean value of fresh mix was significant between treatments (p-value=0,0376).

Figure 4, Results of mean hours before a three degree increase in temperature in relation to ambient temperature in hours in fresh mix, 1 day old and 2 day old samples from treatment and control, as well as P- values of comparisons of hours in fresh mix

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Cow performances

During the experiment, the quantity of water and food ingested by each cow was recorded. The Data from cow intake was false because of recording failure with the scales. Adjustments were made based on the cows average eating speed. As we can see on the figure below, cows fed with the diet containing the additive consumed 57,1 kg of TMR and the control treatment 60,4

kg(+3,3kg/day).These results are not significantly different (p=0,138). The cows took the same time to eat the two TMR (treatment=174,7min/day, control=169,9min/day).

Although feed intake was not affected by the additive, water consumption was significantly differ-ent between the two treatmdiffer-ents. The control treatmdiffer-ent consumed on average 59,5 litres per day of water and the Perstop treatment consumed over 10 litres more on average (70 litre/day) (p=0,008). This increase also meant more time drinking, 58 minutes for the additive against 50 minutes a day for the control treatment, this is 8 minutes more time drinking (p=0,002) which would mean an extra 3,650 litres a year per cow. In the graph below we can see that the control treatment con-sumed more water than the treated treatment in period 3 and that overall drinking time reduced from one period to another in both treatments.

50,0 52,0 54,0 56,0 58,0 60,0 62,0 64,0 66,0

Period 1 Period 2

Period 3

average intake (Kg/day/cow) per treatment per periode

control perstop 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 50 60 70 80

periode 1 Periode 2 Periode 3

Water intake and time drinking during the 3 periodes

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Discussion

The main aim of this study is to test an additive in a TMR mix based on propionic acid, sodium sul-phate and potassium sorbate to improve the aerobic stability of the silage in relation to its time to rise 3°c from ambient temperature. Research shows that an increase in temperature of the feed, reduces cow’s intake and reduced intake results in reduced milk production. In practice, this re-search could lead to a solution to limit the increase in temperature caused by aerobic exposure of silage and allow farmers to make batch TMR for multiple days without compromising the feed qual-ity.

The TMR stability has been improved in the first 24hrs but lost effect after 1 day of activity. The mixture of sodium sorbate, potassium sorbate and Propionic acid have proven their efficiency in regard to previous experiments containing the same composites. The propionic acid has reacted in the same way as other studies such as Chen et al (2016) and is showing benefits of combining the propionic acid to other stability improving agents like Silva’s (Silva, Smith, Barnard, & Jr., 2015) study in 2015 which consisted of mixing potassium sorbate, sodium benzoate and sodium nitrate (nearly the same composition to the additive used in this study without the propionic acid) in a maize silage. They also found a significant increase in stability during the experiment. Although this current experiment did not look at the yeast content in the TMR indicating a biological destruction, we could expect to see a lower concentration of these yeasts similar to the Silva (Silva, Smith, Barnard, & Jr., 2015) trial.

The additive seemed to have lost effect after 24hrs because after this time period the two treat-ments did not show any significant difference. It may suggest that the additive could not cope with the developing yeast and fungi fed by the oxygen and thus deteriorating the TMR stability, decreas-ing dry matter and therefore the quality of the TMR. This experiment did not, but this could have been beneficial, weigh each sample before and after the 7 days in the stability monitoring chamber to conclude the decrease in DM.

The cow performances were very significant on water intake but did not show any TMR intake in-crease. This increase could be explained by the additive primary composite, Sodium sorbate, which is a salt. Salt is proven in many studies to increase the water intake because of its absorbing proper-ties (Agricultural research Council, 1980) (Andersson , 1984). With 300g of additive containing 80% sodium sorbate, this might explain an increase in water intake for the treatment receiving the addi-tive.

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The feed intake data proved difficult to collect because of the reliability of the measuring scales, after some adjusting based on average intake speed, realistic intake data was compared between treatments. One cow tended to throw the TMR out of the bins therefore changing her actual in-take, another cow was lame during the first period and did not consume as much as in the other periods, these cows were also recalibrated with their normal intake speeds.

Results for feed intake did not prove significant, cows ate the same amount in both treatments; while the TMR containing the additive was more stable during the first 24h, the TMR was only dis-tributed after 24h (it was made the previous day and stored in a room). At this point the additive had a reduced effect on the silage stability, so cows from both treatments was receiving feed that was decreasing in stability at the same speed during the time the cows had the TMR in the bins. The study aimed to look at the intake performance in a first instance but also checked the milk pro-duction and quality to see any irregular activity. These results were compared and had found no dif-ference for milk production and cell count but did show a significant increase in the treated treat-ment for TB, TP and lactose content but these need to be put in context. In effect, only 2 milk sam-ples were taken from the herd in each period representing 6 samsam-ples per cow which is a low N fac-tor for ANOVA analyses. The graphs in annex 3 show a wide standard deviation on the milk quality because of this. Although the cows did not eat more feed, the treated TMR had a better stability, better stability often means a higher dry matter content ( Kleinschmit, Schmidt, & Kung, 2015) and so one can suggest that the TMR containing the additive had a higher amount of nutrients per kilo of feed. These nutrients are available for milk production thus increasing TB,TP and Lactose where otherwise they would have been consumed by moulds and fungi and transformed into gases and water.

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Conclusion

This study has set out to answer the following question: To what extend additive containing Sodium sorbate, Propionic acid, Glycerolpropionater and potassium Sorbate influences dairy cows’ feed intake due to improved TMR stability. Multiple sub questions were asked to clarify answering the main question. This study first tried to determine to what extend the additive influenced TMR stability. The results show that the additive used did improve the TMR stability during the first day of the experiment by 20 hours but found a reduced effect of the additive after the first day

indicating that the additive is not adapted to batch making TMR.

In a second question the study focused on answering the following question: To what extent is dairy cows’ intake modified by using the additive in the TMR ration? To answer this question, the study recorded water and feed intake and discovered a 10 litre increase in water consumption in the group containing the additive, probably caused by sodium sorbate (salt) in the additive. As the TMR was only distributed to the cows 24h after creation may explain why the additive in the ration did not allow a significative feed intake increase as the additive had no significant effect on ration stability after 24 hours.

Although this study aimed to increase TMR stability to increase intake, the study found an increase in stability but no intake increase, perhaps in a follow-on trial the TMR could be distributed as soon as it is made because it is in the first 24 hours that the additive can improve the stability. Perhaps then we would see a difference. Furthermore, the research study did not look at the health issues raised due to an increased salt diet. This study was only 9 weeks long but in practice this diet could be fed for 300 days without a break. The long term herd health issues of this type of diet need further study.

It is for this reason that I recommend more studies on this additive before commercialisation to look at the effect of long-term exposure to this relatively large amount of salty substance

(240g/Day extra) on cow’s health and cow’s intake by giving the TMR immediately after mixing to better evaluate the differences in its stability and milk production. More milk samples should be taken because too few where taken in this trial to put any reverence on positively significant results.

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Annex 2: Concentrate composition

Komplett Fiber 170 Produktbeskrivning

Kompletteringsfoder med spannmål anpassat till spett gräs, t.ex bete eller ensilage av hög kvalitet.

Komplett Fiber 170 är ett färdigfoder anpassade till kor i alla laktationsstadier. Komplett Fiber 170 kompletterar egenskaperna hos mycket bra grovfoder eller högkvalitativt bete. Komplett Fiber 170 innehåller mycket fiber och protein av bra kvalitet vilket i kombination med bra grovfoder/bete ger en bromsande effekt i vommen. Komplett Fiber 170 skall användas till grovfoder med >11 MJ, >165 g rp, >500 g NDF per kg ts. Komplettera alltid foderstaten med 100g Nötfor mineralfoder per ko och dag för att säkerställa tillförseln av vitaminer och spårämnen.

Egenskaper Innehåll Mängd Grovfoderkvalité Spätt grovfoder Näringsinnehåll per kg ts Torrsubstans % 88 Energi, enl SJV, MJ 13,5 Råprotein g/kg ts 170 EPD % 55 AAT g/kg ts 94 PBV g/kg ts 3 Råfett g/kg ts 73 NDF g/kg ts 270 EFD % 42 Stärkelse g/kg ts 296 Kalcium g/kg ts 8,8 Fosfor g/kg ts 6,1 Kalium g/kg ts 8 Magnesium g/kg ts 4,5 Tillsatser Vitamin A IE/kg 4000 Vitamin D, IE/kg 2000 Vitamin E, mg/kg 40 Selen mg/kg 0,4 Koppar mg/kg 10 Norfor parametrar NEL20, MJ 7,1 AAT20 g/kg ts 106 PBV20 g/kg ts 18 iNDF, g/kg NDF 260 Lösligt, g/kg rp 244 Aminosyror, % 81 Fettsyror, g/kg råfett 884

Klimat & Miljö

Kväve, N % av kg vara 2,5

Fosfor, P % av kg vara 0,5 Kalium, K % av kg vara 0,7 Beräknat klimatvärde, g CO2 ekv 367

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