Cows that live in a semi-natural environment, like in Uruguay, where a pasture-based system is common, can get easily over 15 years of age. In barn based systems, however, this is an exception. Apparently, the farm environment is not so good for dairy cows. Most farmers try to provide their cows with their needs. However, their efforts to keep the barn clean and costs of equipment are usually of major importance as well. The modern farmer, though, realizes that an increase in average age of the herd is also beneficial economically. Replacement cows cost a substantial amount of money and labour, which may be earned back in the second or third lactation. Proper conditions in the barn are, therefore, crucial for the results of a farm.
(This article belongs to the proceedings from the Cow Longevity Conference 2013 that took place at Hamra farm, Sweden in August 2013)
Take home messages:
Free stall conditions
1. Free stalls should be designed according to the needs and size of the cows.
2. Bedding should be soft, clean and anorganic
3. Cows should have sufficient grip in the stalls
Stall and cow cleanliness influence mastitis and milk quality. When built to keep cows out, stalls stay clean and workers are happy (3). However, lying costs less energy and is preferred over standing idle by cows. During lying, the blood flow through the udder is 25% higher (37). In a comfortable environment, cows lie for 12 –15 h per day and rise 16 times per 24 h (40,48).
The area used by the cows for lying should allow for normal resting positions. The freestalls must provide cows enough space to:
- Stretch their front legs forward,
- Lie on their sides with unobstructed space for their neck and head,
- Rest their heads against their sides without hindrance from a partition,
- Rest with their legs, udders and tails on the platform,
- Stand or lie without pain or fear from neck rails, partitions or supports and
- Rest on a clean, dry and soft bed.
- The slope of the floor, which is important to keep the stall clean, should be between 4-7°.
Size of free stalls should match the size of the cows
Freestall dimensions should be selected based on the largest cows in the herd. For a heifer group, stall dimensions can be adapted by adjusting the position of the neck rail. Stall dimensions should provide the cows enough forward lunge space.
Figure 1: Stall, which is too short and narrow.
If the stall is too short, the cow may try to get up by rising on the front legs first (like a horse). Alternatively, if the stall makes lying down difficult, the cows may show frequent hesitation before lying down, usually sniffing the ground and moving their heads left and right (48).
A summary of various recommendations is given by Anderson (3). It is clear that a large variation exists, e.g. stall width recommendations for cows > 680 kg vary from 109 – 132 cm. Dry cows are wider and a recent study of videotaped dry cows revealed that the width of the free stalls for dry cows should be at least 137 cm (van Eerdenburg 2010, unpublished results).
To determine the right dimensions for free stalls, a careful look at the cows (behavior/posture, condition, bruises and injuries) and the cleanliness and shininess of dividers and neck rails should confirm that the chosen dimensions are the right ones. A uniform size of the herd is a prerequisite to get the right size for all animals.
A way of determining the right dimensions is relating the size of the free stall to the dimensions of the cows (table 1). Ceballos et al., (9) studied the required space for a cow to lie down. Cows used up to 109 cm (180% of hip width) of lateral space when lying down, an estimate that is within current recommendations for stall width. However, the recommended length of stalls is generally up to 240 cm, whereas the cow requires 300 cm.
Table 1 Free stall dimensions in relation to cow size (27).
Figure 2. Schematic drawing of a freestall. The numbered arrows indicate the dimensions of table 1 (After Irish & Merill, (27))
Dividers should meet the needs of cows
Bad design/placing can even induce bruises on the sides and backs of the cows (3). The partition should be firm, smooth, without sharp bolts or nuts sticking out, and designed to meet the needs of a cow. The form should be such that the cows cannot get stuck under the divider and that there is enough (side) lunge space.
The size or spatial arrangement of bars etc. within the stall may be reducing lying time by around 2.5 h/d or result in cows that lie in the (dirty) alleys (48,55).
Neck rail position should be adjusted properly
The neck rail of the free stall (figures 2 & 3), should be positioned in such a way that the cows cannot defecate/urinate in the stall in a standing position. A general recommendation is to place the rail >210 cm from the rear curb (2 in Figure 2) and >122 cm above the stall bed. It should not hinder the cow when it wants to lie down. This implies that the cow should be able to stand with all four feet in the stall without touching it (36). Furthermore, a position too far from the curb induces diagonal lunging in the stall (3). The positioning of the neck rail is therefore a delicate job. The size of the cows is very important in this respect (34). A large variation in size of the cows complicates a proper positioning. Cows may tell us whether the position is right. If the free stalls are clean and the cows don’t have injuries or abrasions on the withers it is okay. If the neck rail is shiny and/or the cows have abrasions on the withers, the distance to the curb is to short. If the free stalls are dirty and the neck rail is not clean, the distance to the curb is too large. Too much restriction by the neck rail increases the amount of lameness (4). A properly designed and positioned brisket board may reduce some of this restriction because it positions the cows better when they are lying.
Figure 3: Shining neck rail due to frequent contact with the cows.
Cows should have enough space to lunge forward or sideways
The lunge space is the space taken up by the head of the cow as it moves forward to stand up. It is the space in front of the brisket board. Cinematic analysis of standing up movements, indicate that dairy cattle use between 260 and 300 cm of total longitudinal space (from the nose to the most caudal point of the cow). The space needed for the lateral movement range from 60 to 110 cm at the hips. Estimates of space used by the head while lunging, based on the longitudinal movement of the nose range between 22 and 72 cm (9). This is especially important for a row of stalls along walls. The cows may have no room to lunge forward in these stalls. They need therefore a space to lunge sidewards. The divider should not block this space. The early types of dividers were usually problematic in this respect.
The brisket board: yes or no?
The brisket board is meant to help position the cow as she lies down. It should be placed >180 cm from the rear curb, the top of the brisket board should not be more than 10 cm above the top of the rear curb. It is hindering the cow in stretching a leg forward as can be seen in figure 4. The brisket board should be smooth to prevent skin abrasions. A well designed and placed brisket board allows an easier placement of the neck rail. Thus less restrictions in lying down and rising movements. However, a freestall can very well be designed without a brisket board in order to increase cow comfort.
Figure 4: Cow with front leg stretched over the brisket board.
Bedding serves two purposes. Firstly it softens the floor in order to improve comfort and welfare of the cow. Secondly, it keeps the cows and the area they lie on clean. The comfort of a stall will depend greatly on the type and quality of flooring in the stall. Optimal flooring should provide adequate thermal insulation (depending on the temperature), an appropriate degree of softness, an appropriate degree of friction, a low risk of abrasion and should be easy to maintain and clean (41,42).
Bedding should be soft
A soft bedding is very important for cattle (15,42). One has to realize that cows drop on one of their front knees when they are going to lie down. Because there is not much subcutaneous fat, there is no dempening of the force, resulting in a rather painful event for the cow if the floor is hard. One can test the softness of the bedding by letting oneself drop quickly on his knees (knee test) (36). If it hurts for the farmer, it will hurt for the cow as well.
This is usually a good way of convincing farmers to improve the bedding. A large variety of bedding materials is available and in use. Most of the modern types are soft, for the older ones (i.e. rubber mats) the lying comfort is often at a non-acceptable level.
Bedding should be dry & clean
Cows prefer dry bedding over wet material (8). Furthermore, bedding should be dry in order to prevent the growth of bacteria. It is therefore important to cover soft cow mattresses with a thin layer of sawdust or ground limestone, just to keep it dry. Adequate ventilation helps to keep the bedding dry. Doing the knee test for softness, one can stay on the bedding for 10 seconds, with all the weight on one knee. If the knee remains dry, the bedding can be considered as dry enough. In general, a regular (minimal twice a day) cleaning and refreshing of the bedding is required.
Bedding material should be inorganic
Most bedding material is made of organic compounds and, therefore, a risk factor for the growth of bacteria. A high bacteria count in the bedding can be a risk factor for the development of mastitis (22,28,46,53,66). Furthermore, it induces a higher bacterial count in the bulk milk as well (59). Bedding can be made a like a mattress or waterbed. Or it can be composed of loose material like straw, sawdust, wood chips, composted vegetable wastes or manure, sand, ground limestone, shredded paper, wood shavings, etc. (5). Sand and ground limestone are the only materials that are inorganic and that can have low bacterial counts (23,28,59,66).
Cows should have sufficient grip in the stalls.
Cows should be able to lie down and stand up easily in the same way as they do this on pasture. They should not slip or skid. On the other hand, a bedding that is rough could easily cause abrasion of the skin and lead to injured hocks (figure 5) (61).
Figure 5: Abrasion of the hock due to bad or insufficient bedding material.
Cows standing idle < 15%
An easy way to assess general cow comfort in the stalls is the cow comfort index or quotient. It is defined as the number of cows lying properly divided by the number of cows in stalls times 100, measured 1 - 2 hours before milking . No more than 15% of cows should be standing idle in stalls at this time. Cows that are standing when they would like to be lying down will get stressed. Furthermore, the mammary blood flow is increased during lying with 25-50%, [48,65], which is correlated with milk yield [51,61]. The time spent ruminating is also maximized .
Take home messages:
1. Floors should provide sufficient traction.
2. Floors should be clean and dry.
3. Floors should be smooth and in a good condition.
4. Rubber will improve walking
Checking the floor is especially important with respect to two major problems on dairy farms: lameness and estrus detection. The type and quality of the floor of the barn are of major influence on the incidence of lameness, which is a problem on most of the dairy farms these days (33,43,61,63). An incidence of 25% (cow cases per year) is considered “normal”, but costs too much money. When cows are in the pasture the prevalence is substantially lower.
Floor is smooth, clean, and dry
A smooth and clean floor is a prerequisite for a proper grip that allows cows to walk comfortably, without restrictions. If the floor is not smooth, injuries due to local pressure on the sole of the claw may occur, resulting in injury and lameness (25,57). Furthermore, if there is a layer of manure present, the claws will remain wet and soft. This is a risk factor for the development of (inter) digital diseases (6). Vokey et al. (62) investigated the effect of a slight slope compared with a flat surface. They concluded that a slope maintains a drier environment for the feet, an important property that appeared to prevent the formation of hind-claw lesions, even as animals stood on the surface for up to 4.5 hours per day.
Floors in walking areas should be kept as dry and clean as possible. Because any dirt picked up on the hoof will end up in the lying area and severe lameness increases with the percentage of stalls containing fecal contamination (10,44).
The floor should provide a proper grip in order to let the cows walk without restrictions. Often (on concrete floors), cows are observed as if they “walk on eggs”. This is causing stress and reduces the motivation to walk to the feedbunk. Thus resulting in a lower milk yield. Concrete floors can be grooved in order to improve the grip. This is best done when the floor is made (1), but slatted floors can still be grooved after 10 years of use when they get slippery (fig 6). Increasing the surface roughness or compressibility, however, will not overcome the effects of amounts of slurry on the floor (47).
Figure 6. Grooved slatted floor. The concrete is grooved 2 mm wide and deep. In this way cows will have proper grip.
A rubber topping on a concrete floor will improve stride length and ease of walking (18,47). Furthermore, cows prefer to stand on softer flooring, and are more willing to move on and spend more time standing in front of the feed bunk when provided with softer flooring. (7,14,54). The presence of rubber in the alley to the milking parlor reduced the prevalence of clinical lameness in a recent study by Chapinal et al. (10).
Take home messages:
1. There should be no dirty smell inside the barn.
2. The temperature inside should not be >5 °C above the outside
3. There should be no draught or dead spaces
4. The relative humidity in the barn should be between 50-80%
5. Dust and cobwebs are an indicator for poor ventilation
The climate represents the environmental conditions the cows live in. It is important to realize that the conditions in the various parts of the barn may differ. Climatic conditions have, therefore, to be checked at multiple spots in the barn. Moreover, one cannot be satisfied when the average of the measurements meets the requirements. Every single spot in the barn has to meet the reference values. If not, cows will avoid sites with lower quality, thus reducing their available area. This has not only implications for cow comfort but also for the overall performance of the herd.
Ammonia (NH3) is one of the most common toxic gasses in animal barns [19,22]. The concentration should not exceed 4 ppm for cattle. In barns with manure cellars, mixing of the manure can release other gasses as well. Methane (CH4) and hydrogen sulfide (H2S) are often released in large amounts and may cause danger (explosions) and health problems , but if hydrogen cyanide (HCN) (almond-like smell) is present, a serious health hazard is eminent for both cows and humans . It is a highly toxic compound and lethal at very low levels. Mixing of manure, in slurry pits under the barn, should, therefore, take place when there is sufficient wind and ventilation. When mixing slurry, ventilation should work at a maximum level, with every possible opening of the barn open. It is preferable to have the cows outside the barn during the mixing. If an almond-like smell is present during mixing of the manure, one should immediately leave the building.
Toxic gasses can also be a problem when the airflow passes underneath the slats of a slatted floor. In this way the uptake of NH3 and H2S is increased. A smoke test will reveal such a problem and appropriate measures can be taken.
Cows prefer (compared to human standards) a relatively cool environment. The optimal temperature range to house high producing dairy cattle is between –5 and +15˚C (17). Lactating, high producing, dairy cattle have a lower critical temperature (LCT) of –30˚C. This implies that above –30 ˚C they will not need extra feed for maintaining their body temperature (65). For dry cows, this LCT lies between –5˚C and 0˚C. At environmental temperatures above 15 ˚C, lactating cows will reduce DMI in order to reduce their basal metabolic level. As a consequence, they will produce less milk (2,12,13,31,38). Therefore, during warm summer days a farmer needs to supply cooling. If the cows are outside, shade and ample fresh, cool, water is required.
When housed inside, extra ventilation is desired for cooling and fresh air. Natural ventilation will not be sufficient in certain areas and additional ventilators can be required, depending on location and regional climate (12,16,19,21,24,38,51,52,64). In winter, dairy cows are housed in barns in many countries. Due to the short daylight period, the hairs of the cows grow longer (56). This will increase the insulation of the cows and, therefore, lower both LCT and UCT. In moderate climates it is a good custom to shave the cows completely. Besides the beneficial effect on the upper critical temperature, it improves hygiene.
Temperature difference between inside and outside.
Since cows prefer a cool climate, the amount of ventilation should not be reduced when temperatures drop below 0˚C. This will increase the difference between in- and outside temperature. Because of the fact that the difference between the rectal temperature of the cows and the environment increases there is more warming up of the barn air, due to an increased sensible heat loss. The temperature inside the barn should not exceed 5 ˚C above the outside in order to prevent draft and air-born droplet infections (see below) (20,29,30,45). In cold periods the ventilation should thus be increased. However, if the temperature drops below 0 ˚C, precautions should be taken to prevent freezing of waterers, conduits and manure on the floor. Besides pumping the water around continuously, conduits and waterers can be insulated and heated to prevent freezing, floor heating is usually unusual in cow barns. During the summer, the temperature inside the barn should be lower than outside.
The relative humidity in the barn should be between 50-80% (11). Cows on a high production level produce around 10 kg of moisture per day. This is released in the environment of the cows (barn). A high relative humidity is not desirable because it can harm the cows in two ways. Firstly, under warm conditions, they cannot evaporate as much water as they need, and thus they will suffer from heat stress more seriously. Secondly, under cooler outside conditions, the incoming fresh air will cool the warm, humid, air in the barn and since the amount of water, which can be present in the air, is temperature dependent, condensation will occur and an aerosol will be formed. The cows will inhale the aerosol and in this way air born infectious agents can be transmitted very easily since the particles, on which condensation will take place, can be bacteria or viruses. Because surrounded by water, they will survive for a longer period and the cows will inhale them deep into their lungs. Also, the droplets containing viruses and bacteria that are produced by coughing of the cows are surviving longer under humid conditions (35). In these ways, the cows (especially young stock) could get ill but even if they stay healthy, the pressure on the immune system is increased and the energy required can not be used for milk production or growth (50).
High humidity supports the growth of fungi in the barn. These can be seen on the ceiling and walls and can cause damage to the building. Proper ventilation lowered the prevalence of lameness in a recent study, presumably because of a drier floor (Schutte et al., unpubl results). Since lameness is an important reason for culling cows, a lower lameness incidence will increase the average age of the herd.
Although notorious in pig and poultry farming (39,60), dust is usually not seen as a major health hazard in cow barns. However, if ventilation is at a low level, dust can cause serious problems. Especially when a dust load is present over a long time period (32). Dust particles can originate from the bedding material, feed, skin, etc. (39). It is important to realize that on dust particles bacteria and viruses can be transported. Dust can also consist of spores of fungi (32). The above mentioned problems do not only apply for cows, but also for the farmer or visitors (49,60).
Cobwebs are usually seen if there is insufficient airflow and are a good indicator for ventilation quality (fig. 7). With transverse ventilation, however, the airflow can be sufficient at animal level while in the top of the barn dust/cob-webs are observed.
Figure 7. Dust and cobwebs are an indicator for poor ventilation
Take home messages:
1. Cows produce more milk in a more comfortable environment.
2. Cows may live longer in a more comfortable environment.
The question most farmers immediately ask is: “How much is this all going to cost ?” More important, however, is the question: “How much more money will I make when I improve the conditions?” This is all depending on the price that a farmer receives for a kg of milk and that price varies per region and has been fluctuating heavily, so it is difficult to calculate exact numbers. In general, the amount of milk produced, is an indication for the profit of a farm.
Therefore, the correlation between several parameters and milk yield have been calculated and are presented in figures 8 & 9.
Figure 8 Correlation between free stall comfort and rolling herd average of the milk yield (r = 0.33; p < 0.02). The points are the result of the scoring system of van Eerdenburg et al. (58).
Figure 9 Correlation between floor comfort and rolling herd average of the milk yield (r = 0.29; p < 0.05). The points are the result of the scoring system of van Eerdenburg et al. (58).
It is clear that a better environment results in a higher milk yield of the cows, which should result in a better income for the farmer. Furthermore, cows that live in a comfortable environment will stay healthy and thus live longer (26).
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