CONCEPT OF PHASE FEEDING FOR MORE MILK YIELD IN DAIRY CATTLE

Phase feeding is a term used to describe the feeding of several diets for a relatively short period of time to more closely match an animal’s nutrient requirements. When one diet is fed for a long period of time . the feed meets the nutrient requirements of the animal “on average.” However, at any given point in time, the feed is either under or over the animal’s nutrient requirements.

With this type of feeding program, we would expect animal performance to be reduced early, since the animal is not getting the nutrients required to meet established performance goals. Later, when the feed’s nutrient content is greater than the animal’s requirements, we are adding unnecessary cost to production. In fact, in some cases the excess nutrients can be detrimental to animal performance and certainly leads to excess nutrient excretion to the environment.

Through phase feeding , you more closely match the animal’s nutrient requirements and minimize the over- and under-feeding of nutrients. Ideally, to get maximum benefit from phase feeding, diets to be fed and feed budgets are established based on actual animal performance and profitability/performance goals. The correct diets and feed budgets must be established for each stage of production. Information from breeding companies about expected performance in commercial conditions can be useful in establishing expected performance.

The disadvantages of moving from one feed to a phase feeding system includes greater complexity in ordering feed and the potential need to install additional feed bins on the farm. However, with increased pressures on profitability, these disadvantages must be weighed against the benefits of improved animal performance and profitability.

Dairy cows need to consume a lot of feed/nutrients to achieve today’s expected milk production, and feed represents about 50% of the total production costs. 1) Thus, feeding program, more than any other single factor, can determine the productivity of lactating dairy cows & profitability!?. 2) About 75% of the differences in milk production between cows is determined by environmental factors, with feed making up the largest portion. 3) At peak production, may require 3 to 10 times as much as protein & energy vs. late gestation, but the cow’s appetite usually lags behind her nutritional needs.

Milk production Increases rapidly and reaches peak 6-8 wk after calving. But Feed intake Lags behind milk production, i.e., maximum DM intake does not reach until 12 to 15 wk after calving. The Body reserves Make up the difference in the need & supply by mobilizing body stores. Often loose 90 to 135 kg of body wt

Phase Feeding Program/Feeding Guidelines-———

Feeding periods/phases can be divided into four or five phases

1) Phase 1 – First 10 wk of lactation. Peak milk production & body stores are being used to make up deficits in the nutrient intake.

2) Phase 2 – 10 to 20 wk or so of lactation. Maximum DM intake, and the intake is in balance with the needs.

3) Phase 3 – The intake exceed the needs. The main period to restore body reserves for the next lactation.

4) Phases 4 & 5 – Dry period, and can be considered as only one phase, but:

a) Phase 4 – Most of the dry period, and replete body reserves & regenerate secretory tissues for the next lactation.

b) Phase 5 – The last 1 to 3 wk of pre-partum. Start increasing grain intake as a means to prepare the rumen for the increased nutritional demands.

Dry period & bred heifers (Phases 4 & 5)————-

1) Cows need a short dry period as rest to prepare for the next lactation. The optimum dry period would be 6 to 8 wk.

a) Shorter that 40 d – Not enough time for udder regeneration, thus may reduce the production rate.

b) Longer than 60 d? – Do not increase the production, and may result in excess body condition & calving difficulties.

2) Bred heifers

a) Nutrient needs are slightly higher vs. dry cows of similar size – Still growing!

b) Good-quality hay can provide all the nutrient needs during the early gestation.

c) Need some grains along with forages during the last 3 to 4 mo of gestation to support growth & provide nutrients for fetus.

d) As with dry cows, should be in good condition but not too fat at calving.

3) Quality of forage may not be as critical during the dry period, but cows need sufficient feed to support both the unborn calf and to meet body reserves not replaced in the previous period.

4) Nutrient needs can be met with only forages and no grain, but may be fed up to 4 to 6 lb of grain per day (0.5% of body wt) depending on the condition. (DM intake is approximately 2% of body wt!)

5) “Fat cow syndrome” – Feeding high levels of corn silage or grains may cause excess fat deposits in the liver area:

a) Characterized by high blood lipids & fatty livers.

b) May result in calving difficulties, displaced abomasum, ketosis, and others.

c) Less likely to have problems with hay and(or) haylage vs. corn silage.

6) About 2 wk before calving, increase grain feeding, so cows are consuming 12 to 16 lb grain/day at calving (1% of body weight).

a) Helps cows get accustomed to high grain intake needed after calving, and can reduce the occurrence of ketosis during lactation.

b) Best to increase the amount of grains gradually, which may minimize the chance for milk fever. Most grain mixes have a more desirable Ca to P ratio?

c) Feed a low-Ca ration (< 0.20%, reduce Ca intake to 14 to 18 g/d) 2 wk before parturition to those with milk fever problems may be beneficial?!

d) Also, feed a diet with a negative dietary electrolyte balance (-10 to -15 mEQ/100 g DM) may alleviate milk fever problems!

Peak milk production (Phase 1)————-

1) Cows should be brought into peak milk production as soon as possible after calving. Can be done by feeding slightly more grain than recommended until there is no increase in production & then adjusting the amount of grain accordingly.

2) Milk production increases rapidly, peaking at 6 to 8 wk after calving.

3) The most critical period for a dairy cow is “from parturition until peak milk production:”

a) Objective for this phase? – To increase feed intake as rapidly as possible!

b) Increase grain intake 1 to 2 lb per day after calving to meet the energy needs.

c) May want to avoid excessive grain (> 65% total DM) and maintain 17 to 19% acid detergent fiber in diet to reduce rumen disorders.

d) Extra dietary protein permits more efficient use of body fat for milk production because cows are usually losing body weight.

e) More ruminally undegradable protein source (i.e., bypass protein) might be recommended for high-producing cows in early lactation. ▹ The protein need of cows producing up to 5 kg/100 kg body wt can be met by rumen microbial protein, plus normal amount of bypass protein, but cows producing more would benefit form additional bypass protein.

f) Limit urea to 0.2 to 0.4 lb/day. Some research indicates urea is utilized less efficiently when total ration protein level is high.

g) Increasing the energy density of the ration may help cows meet the energy requirement. Feed 1 to 1.5 lb of added fat per day may increase energy intake while maintaining adequate fiber intake.

h) Buffers, such as Na bicarbonate alone or in combination with Mg oxide, may be beneficial during the early lactation – May aid in maintaining ruminal pH, which minimizes acidosis, reduce digestive upsets, and result in increased DM intake.

Peak dry matter intake (Phase 2)-————-

1) To maintain peak milk production, should achieve maximum DM intake as early in lactation as possible. Usually, reached at 12 to 14 wk

2) With maximum DM intake: a) Can minimize the negative nutrient balance experienced during the early lactation. b) A conception rate is greater for ones in positive energy balance, which is an important consideration because cows are usually being bred during this phase.

3) Maximum DM intake will likely to reach 3.5 to 4% of body wt for most cows, but some variations. (Some may consume as much as 5% of body wt?)

a) Grain intake may reach 2½% of cow’s body wt, and forage intake (DM) should be at least 1-1¼% of cow’s body wt to maintain rumen function and milk-fat test.

b) Should feed forages and grain several times daily.

c) High-producing cows (i.e., > 70 lb 4% FCM) should be fed only natural protein and not urea!?

d) Protein?

(1) Percent protein needed may be lower than the early lactation possibly because of the absolute amount of protein being consumed?

(2) Less beneficial effect of bypass protein? – Increased microbial protein synthesis can be stimulated by the increased DM intake?! Still, should try to maintain a balance between ruminally degradable & undegradable protein.

Mid to late lactation (Phase 3)-———-

1) Perhaps, the easiest phase to manage because milk production is declining and the nutrient intake exceeds the needs. (The cow is pregnant at this phase though.)

2) Should keep in mind that young cows are still growing, i.e., the nutrient requirements for growth are 20% of the maintenance requirements for 2-yr-olds and 10% maintenance for 3-yr-olds.

3) Match grain intake to milk production, and avoid wasteful grain feeding to low producers – Perhaps, an opportunity to minimize feed costs during this phase?

4) The NPN may be well utilized, thus can use urea (0.4 to 0.5 lb/cow/day) if needed to, again, reduce feed costs.

5) Feed extra nutrients, if needed, to replace any body tissue lost during the early lactation. Cows are more efficient in replacing body tissue while lactating than during the dry period, but avoid over-conditioning.

Optimizing feed intake during lactation

1) Water content of feed:

a) Important consideration when using ensiled or fresh forages, or other highmoisture feedstuffs such as high-moisture corn, wet brewers grains, liquid whey.

b) The effect on DM intake is less when water is present in the form of fresh forages than it is in the form of silage or other fermented feeds – e.g., DM intake can be reduced when the moisture content exceeds 50% from ensiled feeds, perhaps, partially caused by chemicals in the feed rather than by moisture per se?

2) Frequency of feeding:

a) A minimum of four daily feedings? – Alternating between forages and concentrates might be the best to increase intake.

b) Total mixed ration? – Feeding frequency may not increase DM intake, but may help to stabilize rumen fermentation though!

3) High-producing cows

Obviously, necessary to maximize feed intake:

a) Should have access to feeds for at least 18 to 20 hr/d? May consume their daily intake in 12 to 22 meals & increase the intake!

b) Consuming more than 4.5 kg of concentrate mix/meal at once can cause acidosis.

c) Many electronic grain feeders are programmed to limit the amount of concentrate consumed by a cow within a short period of time, which would be helpful in alleviating acidosis problem.

+ Feed young growing cows enough to allow for growth, as well as for maintenance and milk production. Best to group cows by production as a means of challenge feeding.

+ In general, more cows are underfed energy than protein. [Most lactation rations will contain 13 to 17% CP and 60 to 70% TDN (0.6 to 0.8 Mcal/lb NEl).]

+ . Finely ground or pelleted forages or grains should not be fed alone to lactating cattle because it can lower milk fat test.

E+ Best to feed some hay when using silage.

+ . Cows in full production will consume 3 to 5 lb of water (including water in feed) for each l lb of milk produced. Have water available at all times and warm water during winter?

+. Give considerations to the relationship of feeds & milk flavor, e.g., cows must be removed from wheat pasture several hours before milking to prevent an off-flavor problem.

+ Added Fat

1) High-producing cows during the first 12 to 16 wk of lactation will benefit most. Cows under heat stress may also benefit.

2) Lactating cows can be fed 1 to 1.5 lb of added fat per day to increase the energy density

: a) Can be blended into the concentrate mix up to 8% or up to 4% to the total ration. Higher percentages may reduce feed intake, reduce fiber digestibility, and cause digestive upsets, especially with unsaturated fatty acids?

b) Whole or processed oilseeds may be fed as a source of added fat.

(1) Oilseeds contain polyunsaturated fatty acids, but they are slowly digested and the oil is gradually released into the rumen, thus allowing for saturation of the fatty acids and less chance of reduced fiber digestibility or milk fat depression.

(2) Oilseeds also provide some protein and fiber. Perhaps, feed 5 to 7 lb oilseeds (whole or rolled) per head daily.

(3) Heat-treated soybeans may have greater protein bypass properties than unheated soybeans. 3) When feeding fat, increase the dietary Ca to 0.9% +, Mg to 0.3%, acid detergent fiber to 20%, and also increase the CP content by 1 or 2%.

Protein ———

1) The need for protein increases even more dramatically at the onset of lactation than the increase in energy needs because milk solids contain about 27% CP.

2) Achieving optimal protein utilization?

a) Supply sufficient amounts of ruminally degradable protein & fermentable energy for maximum microbial protein synthesis.

b) Supply the remainder of the protein needs with high-quality ruminally undegradable protein.

c) Relative proportion in a typical ration? – 60% ruminally degradable protein & 40% ruminally undegradable protein.

d) Supplementing with ruminally protected amino acids can be another means to increase the amount of amino acids presented to the GI tract. But, must supplemet with the most limiting amino acid, which might be difficult to determine.

e) Microbial protein synthesis:

(1) The amount of microbial protein varies with many factors, but perhaps, limited to 2 to 3 kg/d?

(2) High-producing cows (> 5 kg milk/100 kg BW) will likely to benefit form more bypass protein

Bovine somatotropin (BST):

1) Has been approved for use in lactating cows to increase milk production. Expected increase milk production by 8 to 10 + lbs milk per day.

2) It is marketed as “Posilac,” a 14-day prolonged-release BST, and the dose is 500 mg BST injected every 14 days (36 mg/cow per day).

3) Should be given to healthy cows from 9th wk of lactation until drying off.

4) Has no effect on basal metabolism and maintenance or digestion of feeds:

a) Directs nutrients away from other body tissues towards the mammary gland.

b) The efficiency of nutrient utilization is not altered, thus increased milk production, and results in a greater requirement for energy and nutrients.

c) Feed intake of BST cows increases within 3-6 wk to support the increase in milk production, thus cows will lose body condition initially.

5) When using BST, dairy producers should score cows for body condition to reduce the incidence of lowered reproductive performance.

Reference-On Request