Dairy Feeding strategy & Diet formulation for the Dairy Herd
by Dr. Ofer Kroll
The general approach in Israel today is to maintain two feeding groups: one for early lactation and another for the rest of the milking cows. In family farms, the one-diet method is the most popular one. Ad-libitum feeding, mainly with TMR and minimal transfer of cows between groups is the preferred feeding method in Israel.
Ration Programming and Feeding Practices
Optimal planning and rationing have always been desirable goals from a professional and economic point of view; however, special care must be taken while adjusting planning to management.
Group feeding system using a weighing-mixer wagon, represents an important management tool for dairy farms: it improves feed efficiency and rumen fermentation, and provides control of feed intake.
An average daily feed intake in dry matter (DM), ranges from 3.0 to 4.0% of cow’s body weight (BW) and is influenced by milk yield, days after calving, ration composition, NDF content, forage to concentrate ratio, particle size and density of ration. In Israel, the influence of the hot season has a sound effect, contributing to a 10-15% decline of feed intake in summer, as compared to winter.
Feed intake, especially for cows at peak lactation, constitutes the major limiting factor for provision of nutrients. This is the starting point in any system for rationing and planning. Perhaps, if in the future we count with protected proteins and fats, we shall be able to overcome the limitation of conventional energy intake.
Feeding TMR ad-libitum we can record data of grouped feed intake, but not of individual cows. It appears that the maximum individual intake by high yielding cows reaches up to 4% of their BW (or NDF intake up to 1.3% of BW).
Until the end of the 70′s, the Scandinavian Feed Unit (FU) system was commonly employed for rationing in Israel. It used the average norm of 5 FU/day for maintenance and 0.3-0.4 FU/kg of milk. Since the available amount of roughage is limited, this led to feeding cows with 17-18 kg of concentrates per day, resulting in low feed efficiency. With the increased use of the Metabolic and Net energy (ML, NEL) systems and their higher evaluation of roughage, the importance of roughage was emphasized. Evidently, manipulation of the feeding level cannot be achieved just by changing the amount of concentrates.
Today it is common to use the ME/NEL system for energy evaluation and NDF or ADF for intake and energy estimation. NRC 89-01 in addition to local experience, are the main guidelines for feeding high-producing dairy cows. Under the local low quantity/low quality roughage conditions, high energy concentration is a common practice. The energy concentration for high yielding cows is 1.76-1.77 Mcal NEL/kg DM. Ration fat is 3% to 5%, and various sources of starches are always included.
Years ago, 500-550 gram of crude protein for maintenance and about 70 g/kg of milk were a typical allowance. Today, In the TMR system 16%-16.7% crude protein is the requirement for high yielding cows (in summer and winter, respectively). About 34%-36% of the total protein is UIP (Undegradable Intake Protein) and a large variety of protein sources are a common solution to cover the needs for the different amino acids. Cows in early lactation may be given 18-19% protein/DM.
Under Israel’s conditions of feeding, it is important to estimate the animal’s requirement of NDF, which will allow normal rumen function. The use of intermediate feeds, such as wheat bran or orange peel, takes the amount of NDF to a total of 6-6.6 kg/day (30%-34% of total DM), but forage NDF is not more than 3.4-3.6 kg (17%-18% of total DM). Particular attention must be paid to the physical structure of feeds; straw and similar stuffs, when finely chopped loose some of their efficiency as roughage.
For a correct design of rations, especially when using computerized linear-programming, there are some basic assumptions which may not have any justification in literature or in research, but that appear -from field experience under local conditions- to influence feed intake and performance.
Regarding intermediate feeds: feeds containing large amount of highly digestible carbohydrates -such as orange peels- are limited to 15% of total DM. This group of foodstuffs also includes liquid whey, which is extensively used in dairy feeding.
In the summer, intake declines. Then, it is recommended to provide better quality forage to minimize climatic effects. Cooling cows by the use of sprinklers and ventilation can lower body temperatures by 1-2ºC and enhance feed intake.
Ad-libitum feeding of dairy cows is the common practice in Israel since the 50′s. The goal is to take full advantage of the genetic potential of the animal.
The main problems to be dealt with remain:
- How to increase intake and energy supply to animals.
- How to deal with digestibility of feeds especially when very good forage is not available or in reduced supply.
- How to balance maximum yields with maximum profit.
It seems that simple and properly balanced diets, minimum transfer of cows between groups, with the support of good housing, health control, fertility and breeding are the key to success for any dairy farm.
Heifers rearing are one of most important task in dairy farming. We aim for high, tall and not-fat animals. To achieve such goals we use high energy concentrations at early ages and gradually change to lower levels. At calving (24-25 Mo), BW of 560-600 kg and 138-140 cm of height, are regular.Mistakes while the rearing process of heifers cannot be corrected later, during the productive stages.
Dry cow management
The dry period is of utmost importance in the dairy cow life. A suitable diet may contain high amounts of forage (75-80%) and it includes wheat silage, hay and some wheat straw, supplemented by soybean meal, barley, corn and vitamins. The aim for the dry period length is about 60 days. Extra supplies of energy and protein are planned for the last 2-3 weeks prior calving.
Example of an Israeli diet composition for Lactating Cows
Under Israel’s conditions water is a large problem (amount and cost). Therefore, the forage content in most cow diets is only about 30%. In addition, most of the protein sources and grains are imported, so that their availability depends on supply and costs at international markets. To overcome such handicaps and to cover gaps in our nutritional knowledge, the most popular solution while rationing is to include a large variety of ingredients.
|Nutrients (on DM basis)|
|Net Energy for Lactation – NEL||1.77 Mcal|
|Forage dry matter||32.6 %|
|Forage NDF||18 %|
|Ingredients (% of total, on DM basis)|
|Barley grain (rolled)||5.2||CMS + Urea||1.8|
|Maize grain||21.5||Wheat Silage||26.0|
|Wheat grain||1.7||Wheat Hay||4.4|
|Soda-treated rye grain||5.6||Alfalfa Hay||2.2|
|Soda-treated cotton seeds||1.7||Oil||0.2|
|Soybean meal (44%)||9.3||Salt||0.4|
|Corn gluten feed||4.4||Limestone||1.1|
|Sunflower meal (37%)||2.8||Soda Bicarbonate||0.4|
|Wheat barn||3.7||Magnesium Oxide||0.1|
|Citrus peel||3.8||Vitamin Premix*||0.4|
*Vitamin A, D, E, microelements, biotin, yeast culture