Five distinct feeding phases can be described to attain optimum production, reproduction and health of dairy cows.
Phase 1: Early lactation:0 to 70 days (peak milk production):
At this stage, the dairy cow has low appetite and feeding intake lags behind milk production, hence the cow loses weight (negative energy balance). Excessive weight loss should be avoided through formulation of appropriate rations. The roughage: concentrate ratio of the diet should be 40:60, at 19% Protein content, and fed preferably three equal proportions of 13 kg each as in Table 2.3.2 (a) above.
Phase 2: Peak DMI-70 to 140 days (declining milk production):
This stage is critical in the determination of total lactation yield. Feed intake is optimal; with sufficient nutrient supply, the cow should be able to maintain weight gain, as well as peak milk production. The roughage proportion of the diet should be raised to 50:50, as in table 2.3.2(b) below.
Table 2.3.2 (b) - An example of a TMR formulation based a standard cow whose live body weight (LBW) =500kg, milk yield (MY) = 20lts/day, butterfat =3.6% at 1st calving.
|Napier fresh (18%DM)||30|
|Cotton Seed Meal||1.5|
|High-yield dairy Meal||5|
|Total fresh weight||46.75|
Potential problems during this period include a rapid drop, or decline, in milk production, low fat & protein test, silent heat (no observed heat), and ketosis.
To maximize nutrient intake:
- Feed forages and concentrate several times a day.
- Feed the highest quality feeds available.
- Limit urea to 90mg per cow per day.
- Minimize stress conditions.
Phase 3: Mid and late lactation: 140 to 305 days postpartum. (Declining milk production):
Protein level in the ration should be maintained at 13%; comprising minimum concentrate and high quality roughage. The cow should have a body condition score (BCS) of above 2.8, preferable 3scores (BCS is a measure of body fat deposits on a scale of 1 to 5; where 1 is very thin, and 5 is very obese).
Table 2.3.2 (c) - An example of a TMR formulation based a standard cow whose live body weight (LBW) =500kg, milk yield (MY) = 18lts/day, butterfat =3.6% at 1st calving.
|Napier fresh (18%DM)||30|
|Cotton Seed Meal||0.5|
|High-yield dairy Meal||3|
|Total fresh weight||43.55|
Phase 4: Onset of 60-day dry period (first 39 days)
A good, sound dry cow program can increase milk yield during the following lactation and minimize metabolic problems at or immediately following calving. Forage intake should be the major source of the nutrients. However, inclusion of concentrates is necessary when BCS is less than 3.
Calcium and phosphorus intake at this stage should be supplied in proportions of 60 to 80 and 30 to 40 grams respectively.
Always avoid over conditioning the cow.
Key management factors include:
- Observe body condition of dry cows and adjust energy feeding as necessary.
- Meet nutrient requirements and avoid excessive feeding.
- Change to a transition ration starting 3 weeks before calving.
Phase 5: The dry period (the last 21 days) transitional phase
This dry-cow feeding program is critical to adjusting cows, and due in-calf heifers, to the lactation ration to prevent metabolic disorders.
Introduction of concentrate is necessary to begin changing the rumen from an all-forage digestion to a mixed forage and concentrate environment.
Some suggested management strategies during this period include:
- Provide 3 to 5 kg of concentrate to adapt rumen environment to fermentable carbohydrates and stimulate normal rumen function.
- Increase protein in the ration to between 14 and 15 percent on DM basis.
- Maintain 3 to 5kg of quality roughage in the ration to stimulate rumination.
- Remove minerals from the ration if oedema is a problem.