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Diet chart for cows
- Thread starter budda84
- Start date
Hi
Contact
Dr. G.B. Deshmukh
M.V.Sc. D.A.N. (Italy)
Professor
E-mail gb__deshmukh2005@rediffmail.com
Department of Animal Nutrition
NAGPUR Veterinary College, Seminary Hills Nagpur-6.
Phone No. 2511402/06 Extn. 219, Fax- o712-2510883
\
Conventional wisdom has it that cows should be fed "according to production" and one can seldom read an article on dairying in any agricultural magazine which does not reiterate this notion. It has been known for some time that this approach is biologically unsound, but really practical alternatives have not been offered until recently. As explained in some detail in the manual on the CEDARA dairy feeding program (Jones & Stewart, 1987), milk yield per se is a very poor determinant of a dairy cow's nutrient requirements. Our study of the international feeding standards, in particular the British Agricultural Research Council, now the Agricultural and Food Research Council, has led us to the inescapable conclusion that all of the following must be taken into account if a dairy cow's requirements are to be calculated with any degree of accuracy:
stage of lactation
age of the cow (lactation no.)
live-mass
body condition (body reserves)
butterfat yield
stage of pregnancy
These are not set out in any order of importance because this can vary, depending, in particular, on the stage of lactation and the stage of pregnancy. Table 1 shows clearly how unimportant milk yield can be in determining a cow's requirements. The table also demonstrates the difference between determining
individual cow requirements and the common systems of cow feeding, which treat every cow as a "standard" cow. In this hypothetical situation (Table 1) all cows were offered, ad libitum, a roughage containing 9,59 MJ/kg metabolizable energy (ME) (64 TDN) and 15 % crude protein (CP) on a dry matter basis, an energy concentrate (MEAL) of 11,7 MJ/kg ME (78 TDN) and 8 % CP at 87 % dry matter (DM) and a protein supplement (HPC) of 10,2 MJ/kg ME (68 TDN) and 36 % CP at 90 % DM. The cows also were required to walk 3 km to and from pasture and climb 5 metres daily. The table and figure merit careful study.
Note particularly the effect of live-mass on dry matter intake. It is clear that small cows producing milk with a high butterfat content will require higher quality diets than will larger cows producing less creamy milk. It follows that, all of the many thousands of farmers who have been feeding "strictly according to production" in fact have been underfeeding some cows (particularly small cows and high butterfat cows) and overfeeding others.
Another kind of conventional feeding wisdom which suffers from the same kind of problem as discussed earlier is the philosophy which says: "This pasture can give me maintenance plus 10 litres of milk. Above this level I will feed 400 g of dairy meal for every litre of milk produced." The problem with this "maintenance plus" approach is that it fails to take into account the finite size of the cow's rumen. As the amounts of concentrates added to a cow's diet are increased she will eat less of the roughage on offer. Therefore, the value of the added concentrate is the difference between the nutrients in the added concentrate and the nutrients lost through the reduced intake of forage. The rate of substitution depends on several factors and is not a 1:1 rate except at very high levels of concentrate supplementation. The better the quality of the roughages, the better the concentrate must be to effect an improvement in the overall nutrient intake of the cow. A simple example:
Assume that the rate of substitution is 0,7:1 and that the energy content of the pasture is 9,5 MJ/kg ME (63 TDN). (All calculations on 100 % dry matter basis). One kg of a concentrate such as maize at 13,4 MJ/kg (89 TDN) would supply 13,4 - (9,5 x 0,7) MJ = 6,75 MJ (450g TDN) additional energy, enough for over 1 litre of milk at 4% BF. If no substitution occurred, 1 kg meal would provide energy for well over 2 litres of milk. If the same cow had been fed a meal containing only 12 MJ/kg then 1.4 MJ less energy would be fed for every kg of concentrates added. At say 8 kg of meal, a normal amount to feed to high producing cows, this would mean a loss of 11.2 MJ (750 g TDN), the equivalent of about 2 litres of milk.
ESTIMATING A COW'S FEED REQUIREMENTS
The calculation of a cow's requirements, taking all of the above factors into account, can be done from tables and equations. But this is practicable only for groups of cows, because it is far too time consuming to work out the requirements of each cow in a herd. Nevertheless this approach is particularly useful for quick diagnostic work, e.g. to answer such questions as: "Are the high producers in early lactation on this farm short of protein?". Estimating the cow's requirements is only the first part of the problem. The second and the more difficult part, viz. satisfying the cow's requirements from the available feeds and determining the amount of supplementary feeding, still must be done. To do this with precision is really practicable only with a computer. However, not every farmer has a computer or access to a computer, wants a computer, or should even attempt to feed according to a computer program.
What alternative approach, other than calculating individual requirements on computer, can be adopted to ensure economical concentrate allocation? The dairy cow partitions her food between body reserves and milk production. If she is fed more than she requires for milk production, the surplus tends to be laid down as body reserves. If underfed (the normal situation in early lactation), she will draw on body reserves to maintain milk production. This being so, can the dairyman use this ability to store energy and then withdraw this energy from body reserves to buffer his feeding system? The answer is yes, provided that the feeds allocated come reasonably close to meeting the cow's requirements, and that the cow neither loses mass too rapidly, nor is expected to lose more mass than is biologically advisable (i.e. she must be in good condition to begin with). Conversely, it is uneconomical, and could be deleterious to the cow's health, to feed her to gain more condition than is necessary.
In the "Blue Book" Feeding and Management of Dairy Cattle in Natal (Bredon & Stewart, 1979), an attempt was made to take into account all the factors affecting a cow's feed requirements. The method was relatively laborious and even the 1 400 pages of supplementary feeding tables did not cover all possible feeding situations. The authors attempted to feed cows precisely according to their requirements and they did not take advantage of the buffering effect. The approach was used very successfully by a large number of dairy farmers, but has been abandoned by most as being too time consuming. The new approach suggested here may seem a radical departure from conventional wisdom, but is only an adaptation of the system used, albeit unknowingly, by a large number of farmers.
For details visit Practical Feeding of the Dairy Cow
Regards
Harish
Contact
Dr. G.B. Deshmukh
M.V.Sc. D.A.N. (Italy)
Professor
E-mail gb__deshmukh2005@rediffmail.com
Department of Animal Nutrition
NAGPUR Veterinary College, Seminary Hills Nagpur-6.
Phone No. 2511402/06 Extn. 219, Fax- o712-2510883
\
Conventional wisdom has it that cows should be fed "according to production" and one can seldom read an article on dairying in any agricultural magazine which does not reiterate this notion. It has been known for some time that this approach is biologically unsound, but really practical alternatives have not been offered until recently. As explained in some detail in the manual on the CEDARA dairy feeding program (Jones & Stewart, 1987), milk yield per se is a very poor determinant of a dairy cow's nutrient requirements. Our study of the international feeding standards, in particular the British Agricultural Research Council, now the Agricultural and Food Research Council, has led us to the inescapable conclusion that all of the following must be taken into account if a dairy cow's requirements are to be calculated with any degree of accuracy:
stage of lactation
age of the cow (lactation no.)
live-mass
body condition (body reserves)
butterfat yield
stage of pregnancy
These are not set out in any order of importance because this can vary, depending, in particular, on the stage of lactation and the stage of pregnancy. Table 1 shows clearly how unimportant milk yield can be in determining a cow's requirements. The table also demonstrates the difference between determining
individual cow requirements and the common systems of cow feeding, which treat every cow as a "standard" cow. In this hypothetical situation (Table 1) all cows were offered, ad libitum, a roughage containing 9,59 MJ/kg metabolizable energy (ME) (64 TDN) and 15 % crude protein (CP) on a dry matter basis, an energy concentrate (MEAL) of 11,7 MJ/kg ME (78 TDN) and 8 % CP at 87 % dry matter (DM) and a protein supplement (HPC) of 10,2 MJ/kg ME (68 TDN) and 36 % CP at 90 % DM. The cows also were required to walk 3 km to and from pasture and climb 5 metres daily. The table and figure merit careful study.
Note particularly the effect of live-mass on dry matter intake. It is clear that small cows producing milk with a high butterfat content will require higher quality diets than will larger cows producing less creamy milk. It follows that, all of the many thousands of farmers who have been feeding "strictly according to production" in fact have been underfeeding some cows (particularly small cows and high butterfat cows) and overfeeding others.
Another kind of conventional feeding wisdom which suffers from the same kind of problem as discussed earlier is the philosophy which says: "This pasture can give me maintenance plus 10 litres of milk. Above this level I will feed 400 g of dairy meal for every litre of milk produced." The problem with this "maintenance plus" approach is that it fails to take into account the finite size of the cow's rumen. As the amounts of concentrates added to a cow's diet are increased she will eat less of the roughage on offer. Therefore, the value of the added concentrate is the difference between the nutrients in the added concentrate and the nutrients lost through the reduced intake of forage. The rate of substitution depends on several factors and is not a 1:1 rate except at very high levels of concentrate supplementation. The better the quality of the roughages, the better the concentrate must be to effect an improvement in the overall nutrient intake of the cow. A simple example:
Assume that the rate of substitution is 0,7:1 and that the energy content of the pasture is 9,5 MJ/kg ME (63 TDN). (All calculations on 100 % dry matter basis). One kg of a concentrate such as maize at 13,4 MJ/kg (89 TDN) would supply 13,4 - (9,5 x 0,7) MJ = 6,75 MJ (450g TDN) additional energy, enough for over 1 litre of milk at 4% BF. If no substitution occurred, 1 kg meal would provide energy for well over 2 litres of milk. If the same cow had been fed a meal containing only 12 MJ/kg then 1.4 MJ less energy would be fed for every kg of concentrates added. At say 8 kg of meal, a normal amount to feed to high producing cows, this would mean a loss of 11.2 MJ (750 g TDN), the equivalent of about 2 litres of milk.
ESTIMATING A COW'S FEED REQUIREMENTS
The calculation of a cow's requirements, taking all of the above factors into account, can be done from tables and equations. But this is practicable only for groups of cows, because it is far too time consuming to work out the requirements of each cow in a herd. Nevertheless this approach is particularly useful for quick diagnostic work, e.g. to answer such questions as: "Are the high producers in early lactation on this farm short of protein?". Estimating the cow's requirements is only the first part of the problem. The second and the more difficult part, viz. satisfying the cow's requirements from the available feeds and determining the amount of supplementary feeding, still must be done. To do this with precision is really practicable only with a computer. However, not every farmer has a computer or access to a computer, wants a computer, or should even attempt to feed according to a computer program.
What alternative approach, other than calculating individual requirements on computer, can be adopted to ensure economical concentrate allocation? The dairy cow partitions her food between body reserves and milk production. If she is fed more than she requires for milk production, the surplus tends to be laid down as body reserves. If underfed (the normal situation in early lactation), she will draw on body reserves to maintain milk production. This being so, can the dairyman use this ability to store energy and then withdraw this energy from body reserves to buffer his feeding system? The answer is yes, provided that the feeds allocated come reasonably close to meeting the cow's requirements, and that the cow neither loses mass too rapidly, nor is expected to lose more mass than is biologically advisable (i.e. she must be in good condition to begin with). Conversely, it is uneconomical, and could be deleterious to the cow's health, to feed her to gain more condition than is necessary.
In the "Blue Book" Feeding and Management of Dairy Cattle in Natal (Bredon & Stewart, 1979), an attempt was made to take into account all the factors affecting a cow's feed requirements. The method was relatively laborious and even the 1 400 pages of supplementary feeding tables did not cover all possible feeding situations. The authors attempted to feed cows precisely according to their requirements and they did not take advantage of the buffering effect. The approach was used very successfully by a large number of dairy farmers, but has been abandoned by most as being too time consuming. The new approach suggested here may seem a radical departure from conventional wisdom, but is only an adaptation of the system used, albeit unknowingly, by a large number of farmers.
For details visit Practical Feeding of the Dairy Cow
Regards
Harish