Goats; Sustainable milking, CAE, grazing and feeding

This report has been prepared as a result of my internship at the organic goat farm De full Maan in the period from 27 September to 22 October 2010. The report discusses 4 topics that have been chosen based on experiences during my internship: End-of-life milking, Caprine arthritis encephalitis, grazing and nutrition.

Durable milking

Sustainable milking is continuing to milk for a longer period without having to paralyze again (Schuiling, 2005). Goats can sustain milk yield for 2 to 7 years depending on the persistence of the animal. Long-term milking has actually been used for quite a long time, often by chance due to goats becoming pregnant. In the case of standard lactation, lamination is repeated every year. The animal is put dry shortly before the lambing. When milked through, it is also called down every year, but the animal is not kept dry. Durable milking has several advantages over standard lactation and milking. More and more companies are therefore applying this technique (Schuiling, 2007).

Winter milk

The milk yield with standard lactation and milking proceeds in a peak in the spring and a valley in the winter. However, the demand for goat milk is actually higher in the winter. Some buyers therefore pay a surcharge on winter milk to encourage goat farms to produce more. This is done by bringing the goat rutting season early so that the lambing is done in October - November instead of in March (Schuiling, 2005). However, this technique generates additional costs and labor and does not have equally good results every year. However, enduring milking gives a fairly constant milk yield with a smaller peak in the spring and a smaller trough in the winter (Schuiling, 2007). This means a smaller surplus in the spring and a larger supply in the winter without having to invest extra costs or labor.
production
When the fat and protein production in CVE of the 3 techniques are compared over 2 years, there is virtually no difference.
  • Milking as standard: 155 kg CVE
  • Milking through: 155 kg CVE
  • Durable milking: 154 kg CVE

However, if one looks at the actual production over a period of 2 years, the sustainable fanciers give 13.8% more fat and protein than the standard milked animals. The daily average of the enduring milkers is also higher than that of the standard lactation.

This can mainly be explained by the selection criteria with which the long-term fanciers are selected. In general, goat farmers expect goats with a higher milk yield to be more persistent and therefore better suited for sustainable milking. However, after investigation it appears that this is not true. Low- and middle-productive animals even seem to be slightly more persistent (Schuiling, 2007).

Influence on the processability of milk

Another important question about enduring milking is of course the influence on the processability of the milk.
With standard lactation, the processability of milk decreases towards the end of the lactation period. This is caused by the influence of the udder involution on the composition of the milk (Schuiling, 2007). A decline in casein, α-lactoalbumin and β-lactoglobulin is observed (Bianchi et al., 2004) and an increase in kappa casein (Brown et al., 1995). With long-term milking this process will also take place at the end of the lactation period. However, because this period is relatively shorter than with a standard lactation, the share of milk from end-lactation animals will be smaller. This therefore ensures better processability of the milk with enduring milking (Schuiling, 2007).
An increased cell count also has a negative influence on processability. The cell count increases towards the end of lactation and when an animal has had mastitis. After a comparative study between standard lactation and long-term milking, it appears that even with long-term milking the cell count rises towards the end of lactation but remains lower than with standard lactation. This means that this increase has less influence. This can be explained by the generally larger milk yield from enduring milkers, which has a thinning effect on the cell count. In addition, standard lactations have a greater risk of mastitis due to dry-out before lamination and a reduced immunity around the lamination, which can thus increase their cell count.
In addition, colostrum milk also has a negative influence on processability. During the withdrawal period, however, there is always a large amount of milk from newly sedated goats. Sustainable milking also has a positive influence here, since the goats do not paralyze as often (Schuiling, 2007).

Labor and lambs

After spreading the milk yield, reducing the labor peak around lambing is the main reason for goat farmers to start milking. Since fewer lambs are born, there is of course less work during the lambing period.
This has the additional advantage that there are fewer surplus lambs. After all, only a limited number of animals are needed to maintain livestock. Even if the farm expands its livestock, more animals are usually born with standard lactation than are needed. These surplus animals are then sold to a fattening company but cost the goat farmer more money than they do. Preventing these surplus lambs is not only financially interesting. It also contributes to the image of the goat sector that is seen as an animal-friendly sector (Schuiling, 2007).
The smaller number of lambs in Spain and France is precisely the biggest reason for not going to milk expensive. The circumstances are therefore completely different. The farmers get a good price for their lambs so that enduring milking would be a loss of income. Reducing labor is also tackled differently. The number of animals per farm is usually smaller, making it less necessary to reduce labor. If you want to do this, you will start milking once a day instead of twice. Due to the larger storage capacity of the udders of goats in Spain, the milk yield will still remain at a reasonable level (Van Der Hulst, 2007).

Loss and illness

Since most diseases occur shortly after the lambing and therefore before the selection for enduring milking takes place, it is difficult to make a correct comparison. In general it can be said that most treatments take place during the first 6 months of lactation and that almost no treatments take place during end-of-life milking.
One of the most common diseases is uterine inflammation. Uterine infections are a direct consequence of cancellation and are therefore just as common per lactation in enduring milkers as in standard lactation. Since enduring milkers do not paralyze every year, it will occur much less per calendar year (Schuiling, 2007).
Research shows that the drop-out rate per lactation in enduring milkers (8%) is smaller than with standard lactations (11.1%). Since the duration of lactation with longer-term milking is longer than with standard lactation, the difference in outages per calendar year will be greater. Due to the reduced resistance and the negative energy balance around the lambing, the animals are more susceptible to diseases (Schuiling, 2007). Sustainable milking therefore ensures a smaller dropout by reducing the risks associated with pregnancy and lambing. This leads to better animal health and a longer lifespan (Schuiling, 2005).
A possible consequence of enduring milking is sham. Research has shown that with standard lactation 9% false carriage per lactation is determined and with long-term milking 23.2%. If you look at this per calendar year, there is virtually no difference. It is also the case that covered animals that appear to be pregnant are often transferred to the long-term milk group. It has been established that some enduring fanciers are repeatedly fake pregnant (Schuiling, 2007).
Some companies try to prevent false milkers from becoming pregnant by keeping the animals strictly separated from the goat and by adjusting light regimes in the barn. It has not yet been investigated whether these methods effectively influence the number of sham pregnancies (Van Der Hulst, 2007).

Cons

A disadvantage of enduring milking is the quicker greasing of the animals. This has a negative effect on fertility for the next lactation period. By giving a modified diet this can be solved quite well. Both a mixed ration and a straw - lump ration are possible (Schuiling, 2007).
Another problem is that enduring milking can reduce the selection sharpness for breeding (Schuiling, 2005). Good milk goats are milked for several years in succession, while animals that fat faster will be covered again sooner. As a result, the majority of the lambs comes from the least good animals, causing the flock to decline genetically. A possible solution is to start good goats after milking after 2 or 3 gestures. Young animals have fewer problems due to lambing, which means there will also be fewer losses (Schuiling, 2007).

Caprine arthritis encephalitis

CAE virus

CAE is a slow-acting, infectious viral infection (Tuenter, 2007). The virus belongs to the family of the lentiviruses (Dawson, 1989; Practice study livestock farming, 2002). It is species-specific and therefore only occurs in goats (Animal Health Care Flanders vzw, Z.D.). The virus is related to the trampling disease virus that occurs in sheep (Practice study livestock farming, 2002; Schippers, 2007; Tuenter, 2007). It is also sometimes linked to AIDS in humans (Dawson, 1989; Schippers, 2007; Tuenter, 2007).

Symptoms

The disease expresses itself in various ways, including depending on the age of the animal. However, not all infected animals show symptoms. Those who do show symptoms may show 1 or more. CAE can manifest itself as arthritis, encephalitis, chronic mastitis and interstitial pneumonia (Tuenter, 2007).
Encephalitis (brain inflammation)
In young animals from CAE usually occur as a brain infection between 2 and 6 months of age (Robinson and Ellis, 1986; Tuenter, 2007). It starts with an irregular gait due to sagging of the hind legs. This worsens until the entire hindquarters are paralyzed. This sagging and paralysis then spreads over the rest of the body until the animals can no longer stand up (Dawson, 1989; Tuenter, 2007). Other less common symptoms are blindness, gait, torticollis, tremor, opisthotonus, and hyperaesthesia (Ganter, 1988; Pensaert, 1993; Tuenter, 2007). The animals also often have a rough and dull coat (Narayan and Cork, 1990; Tuenter, 2007). However, the animals remain alert and, as far as possible, continue to eat and drink normally. No treatment is possible (Dawson, 1989; Tuenter, 2007). The disease progresses fairly quickly. In 2 to 4 weeks it will lead to paralysis and ultimately to death (Dawson, 1989; Narayan and Cork, 1990).
Sometimes this form of CAE also occurs in adult goats between the ages of 1 to 5 years. Just like with the lambs, the condition starts with an irregular gait that becomes aggravated within 4 months (Narayan and Cork, 1990).
Arthritis (joint inflammation)
In adult animals from the disease occur primarily through inflamed joints. This condition starts with carpal arthritis (Tuenter, 2007). This can occur unilaterally or bilaterally, but it will usually be bilateral (Dawson, 1989). The swelling of the carpi is first mild and painful. As the inflammation progresses, this swelling will harden and become clearly visible (Robinson and Ellis, 1986). It is because of this striking swelling of the knees that the disease is called the 'thick knee disease'. A lot of joint fluid is found in the connective tissue. The moisture can be clear yellow to reddish-brown (Tuenter, 2007) and has a lower viscosity than normal synovial moisture (Narayan and Cork, 1990). The inflammation spreads further over the body along the shoulders, hips and pelvis (Tuenter, 2007). Normally arthritis is accompanied by stiffening of the joints and lameness. However, some goats have a normal gait despite clearly swollen joints (Dawson, 1989). Other symptoms that often accompany this condition include weight loss, poor general condition, reduced milk yield and a dull, rough coat (Ganter, 1988; Narayan and Cork, 1990). Because the animals often lie down, bedsores may occur and extra attention must be paid to hooves that no longer wear off sufficiently (Narayan and Cork, 1990; Tuenter, 2007).
The symptoms usually manifest themselves around the age of 1 to 2 years (Kuiper, 1992; Practical study livestock farming, 2002; Tuenter, 2007). No cure is possible here either. The animal usually dies from additional symptoms at the age of 5 to 8 years. The pain of the animal can be relieved by giving it a soft surface to rest on and administer painkillers (Tuenter, 2007).
The evolution of the disease varies from animal to animal, it can remain stable for a long time or, on the contrary, get worse. The disease often peaks when the animal becomes stressed (Dawson, 1989; Tuenter, 2007).
chronic mastitis (udder infection)
Udder inflammation is a common symptom but is not always reported because the symptoms are not immediately visible or recognizable (Dawson, 1989). The milk production can sometimes decrease but the udder usually does not get thick or warm (Ganter, 1993; The animal health service, Z.D.). As the inflammation develops further, the udder tissue dries up. With palpation one feels that the udder tissue is hard. Sometimes there are also nodules in the tissue. The goat gets a so-called meat diaper. The inflammation usually occurs in 1 udder half but it also happens that the entire udder is inflamed (Kuiper, 1992). Milk production is declining further and can eventually stop completely. However, the composition of the milk remains normal (The Animal Health Service, Z.D.). Chronic mastitis mainly occurs in lactating goats, but it can also occur in young animals that are not yet lactating (Kuiper, 1992).
Interstitial pneumonia (pneumonia)
Despite the fact that CAE almost always leads to some lung changes, this condition usually remains subclinical (Kuiper, 1992). Chronic progressive pneumonia sometimes occurs in adult animals (Dawson, 1989). This is expressed in the beginning by accelerated breathing with small efforts. The goat will also start coughing (Tuenter, 2007) and will eventually suffer from shortness of breath, even during rest (Robinson and Ellis, 1986).

Diagnosis

Because an animal can sometimes be infected for years without showing symptoms, it is difficult to determine CAE with certainty on the basis of this. Other methods are virus isolation, polymerase chain reaction (PCR) and serological tests; The agar gel immunodiffusion test (AGID) and enzyme-linked immunosorbent assay (ELISA).
In practice, serological tests are mainly used by the easy sampling and the cost aspect (Knowles, 1997). ELISA is applied routinely (Practical Research on Livestock Farming, 2002; Tuenter, 2007; Animal Health Care Flanders vzw, Z.D.). These tests show the infection by the presence of antiviral antibodies in the serum. These antibodies are usually made shortly after the infection, but sometimes only after months or years. It even happens that an infected goat never produces antibodies (Adams et al., 1983). These animals are therefore classified as serologically negative in a test, but do infect other animals. Sometimes these animals can show symptoms (Pensaert, 1993). It may even happen that an animal found to be serologically positive is again negative in later tests (Dawson, 1989). Serological tests are therefore more suitable for determining infection within a group than for individual diagnosis (Robinson and Ellis, 1986; Kuiper, 1992). In animals younger than 90 days, it is difficult to make a diagnosis through serological tests by the uptake of the antibodies through breast milk (Dawson, 1989; Kuiper, 1992).

Contamination

The greatest risk of infection is between the mother and the lamb. Lambs are mainly infected through colostrum milk (Narayan and Cork, 1990; Practical study livestock farming, 2002) but also saliva (Rowe and East, 1997; Practical study livestock farming, 2002), urine and manure are sources of infection (Tuenter, 2007).
Adult animals can also become infected by coming into contact with saliva, manure, urine or milk from an infected animal (Practice study livestock farming, 2002; Tuenter, 2007), by personal contact and even by breathing over short distances (East et al. , 1993). The virus can also be transmitted by people who have come into contact with an infected animal (The Animal Health Service, Z.D.).
Sheep can be carriers and therefore spreaders of CAE but they do not get the disease itself (The animal health service, Z.D.). However, the chance of infection of goats by sheep is small (Practical study livestock farming, 2002).

Fighting

There is no treatment for CAE. Some symptoms can possibly be relieved by, for example, giving painkillers and anti-inflammatory drugs (Tuenter, 2007). The emphasis is therefore on preventing and combating the disease instead of treating it.
The best method to prevent CAE infection is the motherless rearing of lambs. The lambs must be separated immediately after birth from the possibly infected mother animal. The lamb may not have contact with the mother; it must not be licked and must not come into contact with manure or urine. The lambs receive colostrum milk for the first 3 days from a CAE-free goat, beef colostrum or artificial colostrum. They are then fed with CAE-free goat milk, beef milk or artificial milk (Adams et al., 1983; Practical Research on Livestock Farming, 2002; Tuenter, 2007). This is done with the help of teat buckets or so-called lamb bars. This exists in different versions. This technique is also used in CAE-free certified companies to prevent recontamination (Practical study livestock farming, 2002).
By serologically testing animals older than 6 months, infected animals can be detected early (Practice study livestock farming, 2002). It is best to remove these animals (Practical Research on Livestock Farming, 2002; Tuenter, 2007; Animal Health Care Flanders vzw, Z.D.). However, this is not always financially feasible in practice. That is why infected animals are set apart at least 2 meters away from the healthy animals (Rowe and East, 1997).
Goat farmers in Belgium can voluntarily participate in a control plan for which they can receive a CAE-free certificate. A company is declared CAE-free after all goats, older than 12 months, have been serologically tested twice with an interval of 6 to 12 months and all tests were negative. The obtained certificate is then valid for 1 year. The animals must then be tested again 11 months later. If the result is completely negative, the certificate will be extended by 1 year. After 2 consecutive 1-year extensions, the certificate can be extended by 2 years (Dieren Health Care Flanders vzw, Z.D.).
There are a few other measures to prevent infection. For example, you can first milk the CAE-free goats for the infected goats and the young goats for the old ones (Rowe and East, 1997). Furthermore, it is best to buy new animals from a certified company (Dieren Health Care Flanders vzw, Z.D .; Practice study livestock farming, 2002; Tuenter, 2007; The animal health service, Z.D.).

Pasture at organic goat farms

Grazing is important for allowing more animal-specific behavior of the goat and is therefore important for the image of the sector (Van Eekeren, 2002). It is also a clear way to distinguish more between an organic and a conventional goat farmer (Pijlman , 2008).

Pasture system

There are 3 meadow systems; strip grazing, pastures and standing pastures. These 3 methods all have their advantages and disadvantages. The best method depends on the circumstances at the company. For example, the number of animals on the farm in relation to the surface area available for grazing must be taken into account. Labor and gastrointestinal infection are also important factors (Van Eekeren, 2002).
Strip grazing
With strip grazing, the meadows are divided into small plots with the help of movable closures. The goats are placed on a different plot every day. It is the most labor-intensive method. However, the goats do get fresh grass every day, which means that the quantities absorbed are more constant. It is also an effective method to minimize the infection pressure with gastrointestinal worms. There will, however, be more trapping due to the higher concentration of animals (Van Eekeren, 2002). Strip grazing is most commonly used in practice (Koopman, 2002; Van Eekeren, 2002). A survey by the Louis Bolk Institute (2002) shows that companies that use this method have on average a larger number of animals but also the largest area of ​​pasture, which means that they have a smaller number of animals per hectare of land compared to other companies.
Migrate
When grazing, the goats are moved to a different meadow every few days, partly depending on the supply of grass (Pijlman, 2008). To maintain the peace when grazing, it is best to keep the animals on the same meadow for a little longer. The infection pressure of the gastrointestinal worm must then be taken into account (Van Eekeren, 2002).
The ideal cutting height is between 10 and 12 cm (Pijlman, 2008).
Standing pastures
With standing pastures, the goats remain on 1 meadow for a longer period of time. This method is the least labor-intensive and also provides the most peace for the goats. It does, however, cause a high infection pressure for gastrointestinal worms (Van Eekeren, 2002).
The grass is used the most for stand pastures. After a while, however, odor nuisance and contamination from manure can arise, which means that the goats will eat less (Van Eekeren, 2002). It is therefore better not to leave the goats on a meadow for longer than 70 days (Pijlman, 2008). Stand pastures are mainly used by companies with a smaller area of ​​available pasture (Van Eekeren, 2002). The ideal cutting height is between 12 and 15 cm (Pijlman, 2008).

Gastrointestinal infection

The most common species are Haemonchus contortus, Teladorsagia circumcincta and trichostrongylus spp. The Haemonchus contortus is the most harmful worm due to the relatively large amount of blood, 0.05 ml, that it absorbs per day. Goats are more sensitive to worms than most other cattle. They do not develop full immunity against gastrointestinal worms. They can, however, build up pre-immunity, which inhibits the development of larvae and egg production. The animals must be lightly contaminated almost constantly to maintain this pre-immunity (Van Eekeren, 2002).
Cycle
The life cycle of these worm species show many similarities, making a general discussion possible.
The adult worms are mainly found in the abomasum and small intestine. They lay eggs here that leave the body with the goat keys.
If the temperature and humidity are high enough, the larvae of the first stage (L1 - larvae) hatch within a day. These larvae shed and develop in 7 to 10 days to the second stage (L2 - larvae) and third stage (L3 - larvae) larvae. The third stage larvae are infectious larvae. They crawl up on the grass so that they are eaten while grazing. In the animal, the larvae develop in about three weeks to the fourth (L4 - larvae) and fifth (L5 - larvae) larval stage and finally to an egg-producing adult worm.
L3 larvae that are absorbed in late summer or fall can, after development into L4 larvae, rest in the lining of the abomasum or small intestine. These larvae develop further in the spring and thus ensure an increased egg excretion during the lambing period (Vellema, 1999).
The development of the larvae in the pasture and the viability of the L3 larvae depends on the weather conditions. Under tropical conditions the larvae will hatch faster and develop faster (Sani et al, 1995). The L3 larvae will remain infectious for longer in moderate conditions (Eysker, 2001).
Prevention
Strip grazing keeps the infection pressure lowest.
When grazing, grazing takes place within 8 days to keep the infection pressure as low as possible. The meadow is then empty for an average of 28 days (Van Eekeren, 2002), others wait at least 2 months (Van Tilburg, 1997). The meadow must also be mowed at least once for the next grazing. However, in order to draw up a proper preventive grazing plan, more research must be done into the cycle of the gastrointestinal worms and the influences of weather conditions on this cycle (Van Eekeren, 2002).
Grazing is also possible in combination with other cattle such as pigs, cows and horses. They host other types of gastrointestinal worms, which reduces the infection pressure with mixed grazing (Van Eekeren, 2002).
Studies in New Zealand show that certain herbs, such as Chicory, roll clover, Lotus pendunculatus and Hedysarum coronarium, reduce infection pressure.
Research is also being done into larva-catching fungi. The fungus Duddingtonia flagrans, which grows in manure, is capable of catching and killing the larvae of most gastrointestinal worms (Larsen, 1999).
With a high infection pressure on a parcel, it is better to mow for a year or to use a crop rotation with a forage crop (Van Eekeren, 2002).
Therapy
If an infection has been established, worming can be done with products that contain anthelmintics and garlic oil. Walnut leaf is also supposed to work against worm contamination, but this is not officially considered to be worming (Van Eekeren, 2002).
Worming may not be applied more than necessary. Deworming agent has a negative effect on the environment and especially on the insects that live on the manure (Van Eekeren and De vries, 2007). Care must certainly also be taken for the development of resistant worms.

Influence of pasture strategies on milk production

Comparison between the meadow methods and the stable
During a three-year study, milk production was compared between a group of goats in the stable and a group that was grazed according to the grazing system. The first year the milk production of the goats in the stable was higher and the second year lower. During the third year there was virtually no difference between the two systems (Lefrileux et al., 2008).
A study with the same design but with standing pastures instead of pastures did not show a significant difference in milk production (Lefrileux et al., 2008).
When one compared the milk production for two years of a group of goats in the grazing system and a group in the pasture, there was also no difference in production. During the first year, production was more constant with the standing pastures (Lefrileux et al., 2008).
A higher milk production and fat content were measured when goats were grazed on 31 February as opposed to goats that started to feed on 31 March (Lefrileux et al., 2008).
Influence on the milk composition
The milk composition is determined by, among other things, the botanical composition (Van Eekeren, 2002). A study on the fatty acid composition of milk in the alpine mountain region, the Mittelland and the lowlands, conducted by the Eidgenössische Forschungsanstalt für Milchwirtschaft (2001) shows that regions above 1300 meters are favorable for an increased nutritional value of milk. This is due to the difference in supply on the meadows and due to a greater variation in the supply. For example, there are more than 150 species in the mountain grasslands, while in the low-lying artificial meadows in the lowlands there are only about 8 species. There are several plants that have a positive influence on the single and multiple unsaturated fatty acids. Dandelion, blackberry, meadowsweet, strawberry, parsley and wild carrot all have a positive influence on this. Butterflies and grassy plants increase the saturated fatty acids (Baars, 2001).

Pasture growing

As mentioned earlier, the botanical supply and the degree of variation have an influence on the milk composition and the health of the animals. It is therefore important to choose a correct composition. In practice, however, little variation is given.
The most common crop is grass / clover which mainly uses a BG5 mixture consisting of 56% English ryegrass diploid, 14% timothy, 14% meadow longflower, 3% field meadow grass, 3% white meadow clover and 3% white cultivated clover (Van Eekeren, 2002).
Grass
With the grass species, goats seem to have a preference for breeding. Given the characteristics of the grass, however, it is not desirable to have it in the meadow to a higher degree. Italian ryegrass, crossed ryegrass and early English ryegrass are also not always suitable. These grasses have a high sugar content in the spring and therefore a low crude protein content. In combination with the low structural value in the spring, this can cause enterotoxaemia.
Usually a mixture with English ryegrass and Timothee is chosen (Van Eekeren, 2002).
Clover
Red clover seems to meet the nibbling needs of goats the most. Given the often low persistence of red clover, it is recommended to use the Merviot variety which is the most persistent. With white clover, culture clover seems to meet the nibbling needs most (Van Eekeren, 2002).
Lucerne
Lucerne is used less on farms. Given the stalky nature and growth of the plant, it comes closer to the natural nibbling needs of goats than grass / clover. However, Lucerne is difficult to maintain in mixed cultivation and cannot cope with grazing and trampling. The Luzelle or meadow alfalfa variety is better suited for this, but only in combination with white clover to keep production and protein levels up (Van Eekeren, 2002).
Herbs
Herbs can be a valuable supplement to the diet. They contain minerals other than grass and may contain substances that are good for your health. Zo bevat smalle weegbree een bacterie remmende stof en verlaagt rolklaver de infectiedruk van maagdarmwormen.
Zoals eerder gezegd hebben sommige kruiden ook een positieve invloed op de samenstelling van de melk. In Nederland en België worden er weinig kruiden op de weide ingezaaid. Indien er wel kruiden worden gezaaid gaat het vooral om smalle weegbree, duizendblad en cichorei (Van Eekeren, 2002).
Bomen en struiken
Aangezien de geit van nature een knabbelaar is zou de teelt meer gericht moeten zijn op bomen en struiken. De eerste keuze van een geit zijn de knoppen, bladeren, jonge takken en de schors van bomen en struiken.
Wereldwijd zijn er veel voorbeelden maar gezien de gras/klaver traditie in onze streken is het moeilijk een systeem gebaseerd op bomen en struiken concurrerend te maken. Toch zijn er enkele mogelijkheden; er kunnen heggen en houtwallen aangeplant worden of er kan snoeihout naar de weide gebracht worden als aanvulling van hun rantsoen. Enkele voorbeelden zijn braam, wilg, els, es en robinia (Van Eekeren, 2002).

Nutrition

Gezien een volledige bespreking van de voedingsmiddelen en voedingsbestanddelen hier onmogelijk is probeer ik toch zoveel mogelijk informatie weer te geven over de vereisten van voeding voor melkgeiten aan de hand van een rantsoenberekening. Gezien mijn stage plaatsvond op een biologisch bedrijf is dit rantsoen uit biologische voedingsmiddelen opgesteld.
De rantsoenberekening is voor een geit van 65 kg in het eerste deel van haar eerste lactatie met een melkproductie van 3l/dag met 3,3% eiwit en 4% vet. De geit wordt tussen de melkbeurten geweid volgens het omweidesysteem.

Energie en eiwit

De melk/eiwit productie en het aantal kg meetmelk worden in verdere berekeningen gevraagd. Deze 2 gegevens worden eerst berekend.
Eerst wordt het aantal kg vet- en eiwitgecorrigeerde meetmelk (Mm) berekend. Dit is het aantal kg melk met 4% vet en 3,32% eiwit. Dit wordt berekend met behulp van volgende formule (Coopman, Z.D.):
Mm (kg)=((0,337+(0,116 x %vet)+(0,06 x %eiwit))x liter melk
Mm (kg)=((0,337+(0,116x4)+(0,06x3,3))x3= 2,997 kg
Vervolgens berekenen we de melk/eiwit productie in gram. Hiervoor gebruiken we volgende formule (Coopman, Z.D.):
E= liter melk x %eiwit x 10
E=3x3,3x10= 99g
Dan kan de VEM en DVE behoefte berekend worden.
De hoeveelheid VEM en DVE zijn niet de enige vereisten aan het rantsoen. Er is ook behoefte aan vitaminen, mineralen en spoorelementen. Verder is de structuur van de voeding en het OEB- niveau belangrijk.

Structuur

Voor melkgeiten is een structuuraandeel van 20% ideaal. Bij minder structuur in het rantsoen vergroot de kans op maag- en darmstoornissen. Een structuurrijk rantsoen stimuleert de penswerking (Praktijkonderzoek veehouderij, 2002).

OEB- niveau

Bij producerende melkgeiten moet de OEB in een rantsoen ongeveer 10 OEB per liter melk bedragen. In dit voorbeeld is dat dus 10 OEB x 3l = 30 OEB (Praktijkonderzoek veehouderij, 2002).

Droge stof opnamecapaciteit
De droge stof opname van een geit is maximum 3% van haar lichaamsgewicht voor ruwvoeders. Bij een combinatie van ruw- en krachtvoeders is dit 4 tot 5% van het lichaamsgewicht (CVB,1997; Praktijkonderzoek veehouderij, 2002).
In dit voorbeeld gaat het om een jaarling dus gaan we uit van een opname van 4%. Dit betekent dat deze geit dus 2,6kg droge stof kan opnemen.
De droge stofopname bij geiten word ook bepaald door de smakelijkheid van het voeder en het aantal keer dat ze per dag vers voeder krijgen. Indien de geiten 2 of 3 maal per dag vers voeder krijgen zullen ze meer droge stof opnemen dan wanneer ze 1 maal eten krijgen. Dit is natuurlijk arbeidsintensiever. Een manier om de arbeid te verminderen en toch meermaals per dag te voederen is bij het voederen een deel buiten bereik van de dieren te leggen. Door het voeder een paar keer bij te vegen krijgen de geiten elke keer vers voeder en moet er maar 1 keer echt gevoederd worden (Praktijkonderzoek veehouderij, 2002).

Rantsoen

Eerst moet bekeken worden hoeveel de geit gemiddeld zal opnemen in de weide, dan pas kan berekend worden hoeveel nog op stal moet bijgevoerd worden.
Volgens het onderzoek van Pijlman Jeroen (2008) neemt een geit gemiddeld 0,62kg DS per dag op in een omweidesysteem van 6 dagen met gras/klaver.
Gezien de geit nog in het eerste deel van haar lactatie is gebruik ik de voederwaarde van gras/klaver per kg DS in de zomer.
We kunnen dus nog 1,98kg bij voeren terwijl ze op stal staan. Het is mogelijk om aan de behoeften te voldoen zonder echt krachtvoer door krachtvoerachtigen te geven zoals triticale, CCM, bietenpulp, aardappelen en lijnzaad.
Er is dan 0,77 VEM en 22,97g DVE teveel. Het zijn kleine overschotten en aangezien de geit in lactatie is vormt dit niet echt een probleem.

Bespreking rantsoen

Structuurwaarde
Lijnzaad, bietenpulp, triticale, aardappelen en CCM hebben geen structurele waarde (Praktijkonderzoek veehouderij, 2002). Gras/klaver en vooral luzerne hebben wel een goede structuurwaarde (Praktijkonderzoek veehouderij, 2002; Govaerts, Lepema en van Eekeren, 2006) en vormen samen 45% van het rantsoen. Het structuuraandeel voldoet dus zeker aan de norm.
OEB niveau
De OEB waarde is iets hoger dan de eerder berekende ideale waarde. Dit kan dus leiden tot een klein mineralenverlies (Praktijkonderzoek veehouderij, 2002; Govaerts,Lepema en van Eekeren, 2006). Het verschil is echter miniem.
Vitamins
Bron basisgegevens: (Smolders, van Eekeren en Govaert, 2010)
Over het algemeen zijn de voedermiddelen arm aan vitamine E, enkel lijnzaad is hier rijk aan en gras/klaver bevat voldoende om in de behoefte te voorzien. Er zal normaal dus geen tekort zijn. Tijdens het stalseizoen moet wel opgepast worden voor een tekort (Van Eekeren en Smolders, 2005).
Aangezien 45% van het rantsoen uit graslandproducten bestaat zal er normaal voldoende β caroteen (vitamine A) aanwezig zijn in het rantsoen. Er is echter wel een negatieve invloed mogelijk door de granen en bietenpulp in het rantsoen.
Vitamine D wordt vooral aangemaakt in de huid onder invloed van zonlicht. Tijdens het weideseizoen zal het dier voldoende blootgesteld worden aan zonlicht en is er geen extra opname nodig uit de voeding. Tijdens het stalseizoen, vooral aan het einde van het seizoen, kan er wel een tekort ontstaan doordat de dieren al een hele tijd niet meer in het zonlicht hebben gestaan (Van Eekeren en Smolders, 2005).
Minerals
Bron basisgegevens: (Smolders, van Eekeren en Govaert, 2010)
Gezien de grote hoeveelheden die aanwezig zijn in luzerne en gras/klaver zal het rantsoen normaalgezien voldoende calcium bevatten. Triticale en CCM zijn wel arm aan calcium.
Triticale bevat voldoende fosfor. Ook op de weide wordt normaal genoeg opgenomen zodat toevoeging normaal niet nodig is.
Magnesium komt voldoende voor in luzerne en gras/klaver. Triticale bevat wel te weinig magnesium.
Triticale, CCM en luzerne hebben zeer lage natrium waarden. Gras/klaver bevat echter voldoende natrium om in de behoeften te voorzien.
Luzerne en gras/klaver zijn zeer rijk aan kalium. Een te hoge opname van kalium kan een negatieve invloed hebben op de benutting van magnesium en natrium.
Spoorelementen
Bron basisgegevens: (Smolders, van Eekeren en Govaert, 2010)
IJzer wordt slecht opgenomen door geiten. Door de vrij hoge waarden die aanwezig zijn in gras/klaver en luzerne zullen er normaal geen tekorten zijn. Een overmaat beperkt de opname van koper en zink.
Vooral triticale bevat veel zink. Ook luzerne en gras/klaver bevatten genoeg zink om aan de behoefte te voldoen. Toch moet er opgelet worden voor een tekort aangezien een verkeerde verhouding tegenover andere mineralen voor een te kleine opname kan zorgen.
Triticale en gras/klaver bevatten voldoende Mangaan om aan de behoefte te voldoen. Er moet wel opgepast worden met het bekalken van zure gronden omdat dit voor een tekort in de gewassen kan zorgen.
Gezien de lage waarden die in de gekozen voedermiddelen voorkomen is er waarschijnlijk een tekort aan koper. Er zal dus extra koper toegevoegd moeten worden aan de voeding, bijvoorbeeld door een mineralenmengsel. Enkele voedermiddelen die wel rijk zijn aan koper en het rantsoen dus mogelijk kunnen verbeteren zijn zonnebloemkuil, cichorei, vlier, es en hazelaar.
Gras/klaver en Triticale bevatten te weinig selenium. De waarden in luzerne zijn echter ruim voldoende om in de behoefte te voorzien.
Jodium komt in bijna alle voedermiddelen voldoende voor om in de behoefte te voorzien.
Er is ruim voldoende zwavel aanwezig in luzerne en gras/klaver. Zwavel moet echter in een correcte verhouding met stikstof voorkomen voor een optimale productie van in de pens gevormd eiwit. Een correcte verhouding stikstof: zwavel is 14,5:1 of nauwer. Bij luzerne en triticale is de verhouding nauwer en bij gras/klaver gemiddeld iets ruimer.
Supplements
Gezien sommige vitaminen en mineralen niet altijd voldoende in de voeding aanwezig zijn worden extra vitaminen en mineralen toegevoegd. Dit kan onder de vorm van een bolus, een liksteen en poeder (Smolders, van Eekeren en Govaert, 2010).
De wetgeving bepaald welke supplementen mogen gegeven worden aan biologische geiten. De vitaminen A, D en E zijn toegestaan. Synthetische vitaminen zijn wel enkel toegestaan indien ze identiek zijn aan de natuurlijke vitaminen. De spoorelementen ijzer, molybdeen, zink, selenium, jodium, kobalt, koper en mangaan zijn toegestaan in verschillende vormen. Mineralen worden niet verder gespecificeerd in de wetgeving (ver 889/2008 5 september, 2008).

Water

Een geit heeft 1,5 tot 2 liter water per kg droge stof nodig (CVB, 1997). Aangezien de geit uit dit voorbeeld 2,6 kg droge stof per dag kan opnemen moet er 5,2 liter water voorzien worden.

Video: Rotational Grazing With Goats and Stress FREE Weaning (February 2020).

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