Introduction
First, let us define what is Total Mixed Ration (TMR). A TMR is a way to feed the cows by combining all forages, grains, protein feeds, minerals, vitamins and feed additives formulated to a specified nutrient concentration into a single mix feed.
Proper nutrition is essential in order for a cow to be healthy as well as optimal milk production. The cow's diet must consist of a mixture of good quality forages, well balanced of grains and protein sources plus minerals and vitamins. This will provide a balance of nutrients for the cows, avoiding any sort of excesses or deficiencies to allow the cow for milk production, growth, and also reproduction. Feeding a total mixed ration (TMR) that contains all the feedstuff and nutrients a cow require will help the dairy cow achieve maximum performance as well as boosting profitability for the farm. Ever since its inception during the 1950s, it is now widely adopted as one of the most efficient and profitable way of feeding high producing, indoor-housed dairy cows in the world. The reason why it is so popular among diary farmers across the globe is because TMR allows the cows to consume as close to their actual energy requirements as possible while maintaining the optimal particle size required for proper rumen function at all times.
Advantages of TMR
Cow will be able to eat a well balanced nutrient ration.
Since all the forages, grains, proteins, minerals and vitamins are all well mixed, this will minimise the cow's ability to pick individual ration ingredients.
TMR reduces the labour cost of feeding cows.
Able to mask the flavour of less palatable feeds such as urea, limestone, fats. By adding the less palatable feeds to TMR in reasonable amounts, there is little to no reduction in feed consumption.
By grouping the cows, grain mixtures can be liberally fed to high producing cows without overfeeding the lower producing cows. This causes a more efficient use of feed.
Milk production has been shown to increase 5% by using TMR as compared to conventional rations.
Due to better rumen fermentation and balanced nutrients being consumed, it has been shown that there is an increase in milk fat.
With the aid of TMR mixers, it makes it much easier to measure the daily feed intake of cows. This will help minimising waste and reduce the cost of feeding.
Disadvantages of TMR
All cows get fed the same ration. Specific ration for individual ration is not possible.
Mixing or blending devices are required for the ration. Feed mixers and weighing equipment can be very costly.
There are some feedstuff such as hay or straw that do not get mixed very well in some of the TMR mixers. To remedy this problem, additional equipment is required to chop the hay or straw before adding to the mixer and this would involve extra cost.
Grouping of cows is not possible if the herd is too small (less than 50 cows).
Cows are usually grouped based on similar milk production and body weight. If there is a large variation in milk production or body weight, some cows will be overfed or under fed, causing an increase in feed cost or loss in milk production.
Grouping Guidelines for TMR Feeding
A minimum of 3 lactating cow groups and preferably 2 dry cow groups is recommended for cost effective TMR feeding. Suggested groups for a TMR fed herd includes:
Lactating Cow Groups:
Fresh cow group (1 - 21 days after calving) - These cows usually have very low dry matter (DM) intake. However, high nutrient is required as they begin lactation. Ideally, the ration should contain a good amount of fibre, for example, 2 - 3 kg of good quality hay. The goal for this group of cows is to move towards high producing group.
High producing older cow (21 - 180 days in milk) - This group is where peak milk production and peak dry matter intake occur. The main goal for this group is to maintain a high milk production.
First lactation cows - It is better for first lactation cows to be grouped together due to social and nutritional reasons. They take longer time to reach peak dry matter intake and milk production than older cows but they are more persistent in maintaining milk production than older cows.
Mid lactation cows (180 - 250 days in milk) - This group of cows should be pregnant and the milk production is lower (about 70 - 80%) compared to the high group. The ideal ration for mid lactation cows are higher forages and less nutrient dense compared to the high producing group.
Late lactation cow group (250 days in milk to dry off) - First lactation cows with over 250 days in milk can mix with this group if there is a lack of space. The ration for late lactation cow group will be high in forage with the priority being maintaining milk production while avoiding over conditioning or fattening cows.
Dry cow groups:
Far-Off dry cows (220 - 260 days pregnant) - The main goal for this group of cows is to prepare for the next lactation cycle. The ration should contain good quality forages in order to achieve maximum rumen fill and rumination. The ration should also contain enough protein and minerals.
Pre fresh cows (2 - 3 weeks before calving) - Cows in this group have low dry matter intake (10kg/day). Ideal ration for this group is a ration high in fibre and nutrient dense. The ration should contain 3kg of grain, 2-3 kg of good quality forage, minerals, feed additives and vitamins.
General Guidelines to Formulating TMR
The main goal when formulating TMR is to optimise dry matter intake. Total dry matter intakes should be consistent with the milk production and breeds. For high producing cows, only good quality forages should be fed. Factors affecting intake include palatability of forages, presence of certain weed or the water quality. Dry matter intake averages around 2% of body weight during the first two weeks post calving.
Ration difference between groups should be kept to the minimal in order to avoid decreasing milk yield when cows are moved to different groups. The differences in concentrate dry matter proportions should not be more than 15% between groups. The level of concentrate dry matter and protein will very much depend on the milk production level and the type of forage used.
In single group TMR systems, the % of concentrate dry matter may be altered. Thinner cows should receive more supplemental feed for more energy while over-conditioned cows should be fed less. As a rule of thumb, it is crucial to follow sound nutritional practices with respect to crude protein, energy, fat, minerals, vitamins and nonfiber carbohydrates for the respective levels of milk production. It is also important to monitor intakes of TMR so that the cows do not over-eat or under-eat.
Moving Cows Between Groups
Cows should be moved to fresh cow group after calving. Healthy cows should be moved to high production group between 14 - 21 days after calving. The cows will then remained in high production group until they are pregnant or the milk production drops to 10% or more below the average of the group or the body condition score (BCS) of the cows is greater than 3.
When cows move in between groups, the milk production usually drops. Here are some rough guidelines to minimise the milk production drop:
When moving cows, it is recommended to move in groups of 4 or more. This is because individual cows will be more susceptible to social changes compared to groups of cows.
Ideal time to move cows is during feeding time in order to minimise fighting or social disruption.
It is encouraged to move cows regularly to get them accustomed to moving and social changes.
After moving the cows to high production group, if within 5 weeks or before 60 days in milk, the cow does not reach average milk production of the group, she should be moved to a lower production group.
When formulating ration nutrient content between groups, avoid any large changes - no more than 9 kg milk production difference. This is to minimised the drop in milk production as cows move between groups.
Day to Day TMR Feeding
To ensure the success of a TMR feeding program, there are several items that need special attention. If they are not properly monitored, the cows will not consume the optimal amount of nutrients for good milk production, reproduction or health.
It is crucial to monitor the changes in feed dry matter. When formulating the rations for dairy cows, it is on dry matter basis and then the amounts of each fed are either on as is or as fed basis. When mixing the ration, it is essential to know the correct dry matter (100 - % moisture) of ensiled forages, the other wet grains and feeds fed in the TMR.
When feeding a TMR, it is a good investment to have a moisture tester and it should be used at least weekly to test all ensiled forages and wet feeds for moisture or dry matter content.
If there is more moisture present than there is in the dry matter, this will result in the feed being fed in larger quantity than required.
If there is less moisture present than there is in the dry matter, this will result in the feed being fed in less than required.
Changes in the dry matter content of feeds can be notified through:
The change in size or volume of the TMR mixed.
There is a higher than usual amount of left over feed the next day. This indicates that the feeds have increased in dry matter.
Less or no left over feed the next day. This indicates that the feeds have decreased in dry matter.
Important to know the daily count of number of cows in a group so that the right amount of feed fed per day is obtained.
There are many factors such as weather conditions or environmental temperature that affect the daily feed intakes. Hence, it is important to increase or decrease the amount of TMR mixed according to daily variations in feed intakes. If the feed intake is consistently 5% more or less than the original amount the ration was balanced for, then the ration should be reformulated using the new changed feed intake amount.
Adding TMR ingredients in a proper order
Important to maintain the length of forage fibre in TMR
It is recommended that hycrop silage, long hay, or other long fibre sources be added last, unless the mixer is equipped with a hay process at which then the hay should be added first.
With auger mixers, a mixing time of 5 minutes should be sufficient. 15 - 20 minutes is too long.
In vertical mixers with one of two center augers, it is highly recommended that dry or long forages be added first. This is then followed by grains, concentrates and finally ensiled forages.
Feed when cows want fresh feed, usually after milking. Most farmers usually feed their TMR once per day. With proper feed access, this would be sufficient but most nutritionist would encourage more feedings per day.
Maintaining adequate feed bunk space and push feed often. At least 18 - 24 inches (46 - 61cm) of feed bunk space is recommended. The ration should be pushed up to the cows often, around 6 - 8 times a day.
Watch out for sorting of the TMR. The dairy cows will tend to take their nose and wiggle down through a TMR to sort out the grains from forage. This will cause the cows to either have mainly grain meals or mainly forage meals, as if they are being fed without a TMR. This will ultimately cause acidosis. The main cause of sorting is dry ration. Water can be added to the ration to reduce sorting. Feeding cows more frequently can help reduce sorting as well.
It is important to check the mixer wagon scales regularly. Scales should be calibrated when there is a lot of weight in the mixer or when it is empty.