Illini DairyNet Papers
The transition feeding phase can be defined by several different time periods. In this paper, the transition time period includes the close up dry cow (three weeks before calving) through the fresh cow time period (two weeks after calving). A successful feeding system and strategy delivers the needed nutrients to each cow to meet her requirements. Four physiological curves impact dairy cow nutrient requirements. Each factor has a pattern as the cow progress through the lactation and gestation cycle.
Factor 1. Milk production curve.
Milk production drives nutrient needs for dairy cows. Peak milk set the lactation curve for cows. Peak milk should occur 40 to 60 days after calving. First lactation cows should reach 75 percent or greater peak milk levels compared to peak milk of mature cows in the herd. For example, if first lactation cows averaged 60 pounds of peak milk while mature cows averaged 80 pounds of peak milk, the ratio is 75 percent (60 pounds divided by 80 pounds times 100). If the ratio is less than 75 percent, first lactation cows are not peaking high enough compared to mature cows. If first lactation cows peak over 75 percent of mature cows, heifers are peaking higher due to genetics, health, and/or heifer rearing programs or mature cows are not peaking high enough.
Factor 2. Milk fat and milk protein component curves
Milk fat and protein levels will vary by breed (Table 2). If milk fat test is below milk protein test by 0.4 of a percentage point or more (for example 2.7 percent milk fat and 3.2 percent milk protein), rumen acidosis can be occurring. If milk protein test is below breed average or drops during lactation, the following nutritional causes lower milk protein could be occurring.
- Low levels of fermentable carbohydrate (lowers microbial protein synthesis)
- Low levels of dry matter intake (reduces the supply of nutrients available for the rumen microbes and cow)
- Protein shortage and/or imbalance of amino acids
- Use of fats and oils as energy sources (fat is not a source of rumen fermentable energy)
Factor 3. Dry matter intake curve
Increasing dry matter intake can minimize metabolic disorders, minimize weight loss, and improve reproductive performance. During late gestation, dry matter intake can decline 5 to 8 pounds. Wisconsin workers concluded that dry matter intake at calving impacted dry matter intake four weeks postpartum (Figure 1). If dry matter is lower than predicted, the nutrient concentration must be increased to meet the cow's nutrient requirements. After calving, dry matter intake slowly increases (Table 3). Dry matter intake for first lactation cows is less than mature cows which must be considered when grain is fed independent of forages, especially in component fed herds. Guidelines for dry matter intake for various phases are listed in Table 1.
Factor 4. Body weight loss and gain curve
Monitoring weight changes provide valuable information on energy status of cows. High producing cows will lose weight to support high energy needed in early lactation. Body condition scoring is a field method to monitor weight changes. The following guidelines can be used to evaluate weight changes.
- One body condition score (using the 1 to 5 system) is equal to 120 pounds of body weight.
- Cows should not lose more than 1 to 1.5 body condition score points (120 to 200 pounds of weight) in early lactation
- Weight loss should be limited to two pounds per day in early lactation avoid negative effects on reproduction and cause metabolic disorders.
- Cow should be at the optimum body condition score prior to drying off (3.25 to 3.75). If dry cows are thin, limit weight gain to one half body condition score (for example, shifting dry cows from 2.75 to 3.25) which represents 60 pounds or one pound of weight gain per day during the dry period.
By evaluating the four factors during the lactation and gestation cycles in dairy cows, six feeding phases or rations can be developed (Table 1). Some farms can top dressing different grain mixtures to achieve the six phase guidelines. On other farms, fewer groups of cows may be needed to meet nutrient needs.
PHASE FEEDING APPROACH TO FEEDING COWS
The second consideration is to consider the various phases of the lactation and gestation periods. The feeding system must provide the needed nutrients to compliment the four factors or curves discussed above.
Phase one (far off dry cows)
Phase one begins at drying off time to 21 days before calving. This period is also referred to as the traditional dry cow period. These cows must be in a separate group (not with the lactating herd). A balanced dry cow program can increase milk production by 500 to 1500 pounds more milk in the subsequent lactation. Thus, phase one actually initiates the next lactation. During this phase, the cow's mammary gland will involute (dries up), the calf is increasing in size, and body weight gain can be occurring. To avoid metabolic disorders, limit weight gain to one pound per day or one half of a body condition score increase (from 3.0 to 3.5 for example). Dry matter intake can vary from 1.8 to 2.5 percent of the cow's body weight. The amount of grain fed can vary from 2 to 7 pounds per day. One to two pounds of grain serve as a carrier of minerals and vitamins. Do not depend on free choice mineral consumption to meet the mineral and vitamin needs for the dry cow and developing calf. Higher levels of grain are needed if cows are thin, young cows need to grow, environmental stress (cold weather) is occurring, and/or low quality forage is fed. Feeding 15 to 25 pounds of corn silage (as fed basis) or 5 to 8 pound (dry matter basis) can provide additional energy from forage, lowers calcium and potassium levels, and improves ration palatability. Table 1 lists the recommended level of nutrient for phase one dry cows. Strategies for the far off dry cow (phase 1) ration are listed below.
- 12 to 13 percent crude protein
- 60-80 grams of calcium (lower 15% for Jersey cows)
- 30 to 40 grams of phosphorous (lower 15% for Jersey cows)
- Limit salt intake to one ounce
- Force feed trace minerals and vitamins
- Provide one third of the ration dry matter as corn silage
Phase two (close up dry cows)
Phase two (close-up dry cow period) starts 21 days prepartum to calving. If this period is less 10 days, 24 percent of the dry cows will have not receive the phase two ration for the minimum five days needed to achieve desired benefits. Iowa workers identified four physiological goals that the close up dry cow program must achieve.
- Adapt the rumen for the higher energy diet fed postpartum
- Maintain normal blood calcium levels
- Build and stimulate the immune system
- Maintain a positive energy balance to avoid fatty acid infiltration and subclinical ketosis
Increasing the level of grain shifts rumen microbes that can ferment high energy diets and stimulate rumen papillae to elongate and increase papillae surface area. Energy balance can be negative for several reasons.
- Dry matter intake may be 15 to 30 percent below phase one dry matter intake.
- The unborn calf is rapidly growing requiring more nutrients.
- Cows with twin pregnancy have lower DMI, earlier decline in DMI, and a great conceptus mass.
- Formation of colostrum and mammary tissue regeneration.
Body weight loss can be occurring and ketosis risk increased due to fat mobilization. Non-esterified fatty acid (NEFA) originate almost entirely from mobilized fatty. Diet fatty acids are transported as triglycerides and phospholipids. The presence of NEFA in plasma above normal (>0.3 mEq/l) indicates that fat is being mobilized in response to negative energy balance. Plasma NEFA begin increasing 3 to 10 days prepartum, peaking at calving (0.5 to 0.8 mEq/l), and declining postpartum (< 0.6 mEq/l) in healthy cows. Table 1 provides nutrient guidelines for phase two. Management strategies during the close up dry period (phase two) are listed below.
- Increase grain to 5 to 8 pounds of dry matter
- Increase crude protein to 15 to 16 percent using undegraded intake protein (UIP) sources
- Limit added fat to 1/4 to 1/3 pound per day
- Maintain 5 to 8 pounds of long forage
- Consider feeding 7 to 10 pounds DM from the high group TMR (contains UIP, fat, grain, and higher quality forages) plus the phase two grain mix and long forage
- Reduce supplemental sodium
- Add anionic salts to prevent low blood calcium
- Add yeast culture (10 to 120 grams per day depend on the product selected)
- Add niacin (6 grams per day)
- Drench with propylene glycol (1/2 pound) starting 3 to 7 days before calving or feed calcium propionate (1/3 pound) if subclinical ketosis is occurring
Phase three is the fresh cow phase beginning at calving to 2 to 3 weeks after calving. The key management factor is the ability to monitor and observe these cows to insure they are healthy when moved to the high group or are challenged with higher nutrient diets. Individual cow management occurs in this phase requiring lock ups or stalls. The following evaluations should be recorded each day to assess the cow's status.
- Monitor feed intake by evaluating how the cow consumes or "attacks" fresh feed. Record the amount or develop a scoring system (1 = 0 to 33 percent consumed, 2 = 33 to 66 percent consumed, 3 = 66 to 99 percent consumed, and 4 = all consumed).
- Record daily body temperatures until temperatures drop under 102.5 degrees.
- Listen for rumen movements with a stethoscope (cows should have 1 to 2 rumen movements per minute).
- Observe uterine discharges for odors and characteristics.
- Conduct a ketone test on the cow's urine or milk to access energy status.
The fresh cow ration should be intermediate between the close up ration and the high group. Wisconsin workers suggest a shift in a ration should not greater than 10 percent increase in a nutrient (for example, changing from 0.70 NE-lactation by 10 percent would be 0.07 unit shift in the next ration or a 0.77 Mcal NE-l). Maintain a "healthy" level of fiber and avoid high starch levels leading to off feed risks. Table 1 lists recommended nutrient levels for this phase. The following strategies can be considered for fresh cows (phase 3).
- Feed 3 to 5 pounds of high quality long forage to maintain rumen function
- Consider a fresh cow top dress mixture that contains undegraded protein and digestible fiber (such as soy hulls or citrus pulp) as an energy source
- Increase the ration nutrient concentration to adjust for lower feed intakes
- Supplement yeast culture to stimulate fiber digesting bacteria
- Adding a buffer pack can stabilize rumen pH
- Provide 12 grams of niacin to minimize ketosis
- Add propylene glycol (1/2 pound) or calcium propionate (1/3 pound) to raise blood glucose
Phase four (early lactation cows)
Early lactation rations are fed to cows from 14 to 100 days after calving. Cows achieve peak milk production, weight loss occurs (providing an additional source of energy), and dry matter intake lags (Table 3). Protein type and level are critical to reach peak milk production. Limit the amount of supplemental fat to maintain dry matter intake. Table 1 lists nutrient guidelines. Feeding strategies for early lactation cows (phase 4) are listed below.
- Feed high quality forage to improve dry matter intake
- Provide sources of undegraded intake protein to meet lysine and methionine needs
- Increase grain energy gradually (maximum of one pound per day)
- Limit the amount of supplemental fat to one pound per day
- Allow for adequate feed bunk space
Phase five (mid-lactation cows)
Cows will be declining in milk production in phase five. Peak dry matter intake has been reached with weight gains occurring. If milk production and/or components decline too quickly, nutrient needs are not being met. The time period for phase five can range from 70 days to 200 days postpartum or until the cow dries off. Injecting with BST will be initiated during this phase. The goal in this phase is optimizing dry matter intake. Table 1 lists nutrient guidelines for this phase. Feeding strategies for mid lactation milk cows (phase 5) are listed below.
- Optimize dry matter intake
- Begin replacing lost body condition
- Raise supplemental fat to desired levels
- Review the need for feed additives
Phase six (late lactation cows)
Some herds will not reach phase six or tail end lactating cows. These cows are pregnant, gaining weight, and milk production is declining six percent a month (first lactation cows) to nine percent (second and greater lactation cows). This phase can begin 200 days after calving and ends when the cow dries off. High producing cows may not reach phase six. Cow should be gaining body weight (1 to 1.5 pounds per day) plus growth needed for young cow if they have not reach their mature size. Table 1 provides guidelines for phase six with feeding strategies listed below.
- Increase the proportion of forages in the ration
- Supplemental sources of undegraded protein can be reduced
- Remove supplemental fat sources
- Eliminate feed additives
- Replace lost body condition
- Target body condition scores of 3.25 to 3.75 at dry off time
- Reduce feed costs per cow per day
If the dairy manager understands the four factors that impact nutrient needs (milk yield, milk components, dry matter intake, and weight loss), several feeding phases can be developed. All dairy managers may not need six phases, but they must manage these changes economically (considering milk yield vs feed costs). Phase one starts with the dry cows, not the lactating cows. If dairy manager can "control" transition feeding programs (phases two and three), metabolic problems will be minimized, and milk production optimized. The feeding system challenge is to deliver these identified nutrient needs.
Table 1. Illinois nutrient recommendations for dairy cows in different stages of lactation and gestation.
|Dry Cow||Milk Cows|
|0 to 21d||22 to 80d||80 to 200d||>200d|
|*DIP:% of CP (DM)||70 (9.1)||60(9.0)||60(11.4)||62(11.2)||64(10.2)||68(9.5)|
|UIP:% of CP (DM)||30(3.9||40(6.0)||40(7.6)||38(6.8)||36(5.8)||32(4.5)|
|SIP:% of CP(DM)||35(4.6)||30(4.5)||30(5.7)||31(5.60||32(5.10||34(4.8)|
|Ether Extract %||2||3||5||6||5||3|
|*Ratio of NFC to DIP (%of DM) =3.5:1|
|Major Minerals in % of DM|
|*When anionic salts are used: mineral/anionic salts (%)|
|Vitamins in IU per Day|
a. Trace minerals: iron (100 ppm), cobalt (0.1 ppm), copper (15 ppm), manganese (60 ppm), zinc (60 ppm), iodine (0.6 ppm), and selenium (0.3 ppm).
b. Ratio of Minerals in Total Ration: zinc to copper 4:1, iron to copper 40:1, potassium to Mg 1:1, copper to molybdenum 6:1, potassium to sodium 3:1, nitrogen to sulfur 11:1
Table 2. Normal milk fat and milk protein relationship for various breeds of dairy cattle in 1998 (adapted from Hoards, 1998).
|Breed||Milk fat||Milk Protein||Ratio|
|(%)||(%)||(% protein / %fat)|
Table 3. Estimated dry matter intake for first lactation (1200 pounds) and mature (1400 pounds) cows for the initial five weeks postpartum (Kertz, 1991).
|Week||First lactation cows||Mature cows|