Nutrition of

dairy heifers and dairy cows

Dr. Éva Cenkvári, Ph.D.

University of Veterinary Medicine, Budapest

Department of Animal Breeding,

Animal Nutrition and Laboratory Animal Sciences

Goals of dairy heifer rearing

Gaining cows in the future, which have

- high-level milk production and

- can be kept in breeeding for a long period.

Nutrition of dairy heifers during rearing

Index of rumen-reticulum:abomasum, %:

Age Rumen-reticulum Omasum Abomasum

Day 0 38 13 49

3rd month 64 14 22

Adult 85 12 4

Proportion of growth of the pre-stomachs and the abomasum.

Periods of calf rearing

1. Birth (40-50 kg BW):

colostrum, skim milk, acidified milk,

milk replacer

from the 2nd week: calf starter concentrate (18% CP)

+ hay ad libitum

2. Weaning (80-110 kg BW): days 60-90

prerequisite: (0.8 kg concentrate + 0.5-0.6 kg hay)/day

3. Postrearing (180-200 kg BW): months 5-6

(2-2.5 kg concentrate + roughages ad libitum)/day

goal: 800 g body weight gain/day

Sexual maturity

- Correlates with body weight (BW)

(fat percent)

and not with age;

- 20% of BW is ‘missing’in females: underdevelopment of ovaria,

- 25% in BW is ‘missing’in males:

no clinical signs.

Parameters to follow

• Body weight

• Wither weight

• Body length

• Hearth girth

• Body condition

scores (BCS)

Definitions of body development

Isometric growth: from birth to day 90

Allometric growth:

100 kg of BW until puberty +2-3 cycles

Isometric growth:

- growth of organ(-part) (digestive and sexual organs, mammary gland) and growth of body weight are the same rate

- onset of puberty (time of the 1st oestrus) is according to the BW (250-280 kg)

- danger of fat deposition from birth until the 90th day

(or until the first calving) →

- GH and mammary parenchymal DNA decreases

Disadvantages: decrease of life span, calving difficulties,

low milk production

Recommendation of NRC (2001): 70-75% BW of an adult cow after the first calving, 900 g gain/day.

Allometric growth:

- growth of organs is not proportional (e.g.

mammary gland) →

- different growth rates of the body parts;

- from a BW of 80-100 kg until sexual maturity

(+2-3 cycles)

- the growth of body is significantly faster than

that of body weight

Definitions of body development

Isometric:

- until the first calving,

- rate of growth of different parts of body.

(danger of fat deposition; GH and mammary parenchymal

DNA decrease)

Onset of puberty: according to the BW (250-280 kg)

Disadvantages: decrease of life span, difficulties of calving)

NRC (2001): 70-75% BW of an adult cow after the first calving, 900 g gain/day.

Heifer rearing technologies

- Same rearing technology until the end of calf-rearing;

- Exemption: beef calf production.

Development of the concept:

• 700 to 800-850 g/day to 1000 g/day

Heifer rearing

a. Experiment (Huszenyicza and Fekete, 1988) with 3

groups of heifers

1. Extremely moderate feeding level

2. Medium intensive feeding (like NRC)

3. Small framed, but well-conditioned animals

b. Cornell University (Ithaca, NY): more intense

Experiments on raising of heifers

• Results:

Group 1: low BW gain, late start in breeding

(after 18 months, below500 kg BW at calving);

Group 2: daily weight gain: 600-700 g/day,

getting into breeding before the 18th month of

age, BW > or = 500 kg BW;

Group 3: small frame, well-fattened body,

successful insemination until the 18th months of

age, 500 kg BW at calving.

Experiments on raising of heifers (cont.)

Conclusions:

1. Puberty and oestrus is correlated with body weight

but not with age or body size.

2. Successful insemination: at a BW > or = 350 kg

resulted in calving at age of 23.5-24.8 months.

Important:

Control of intensity level of raising:

checking BW gain monthly (at least);

(min. 20-21 kg per month; optimal: 22-24 kg per month)

Nutrition of dairy heifers

Same rearing technology until the end of calf-rearing;

exemption: beef calf production;

It should not be intense or „white-meat calf”.

Nutrition of dairy heifers (cont.)

• Calves for breeding: balanced rearing:

milk replacer + concentrate (ad libitum),

hay

Difference: in the intensity of rearing

having the aim of

1. breeding or

2. fattening.

Goal of heifer rearing

• Prerequsites of succesful insemination/mating:

350 kg BW, 13-15 months,

wither height: 110 cm.

Arguments: more intensive raising is necessary????

Nutrition of dairy heifers (cont.)

5 types of rearing according to the intensity:

1. Very slow;

2. Intense;

3. Moderate;

4. Physiologically intense;

5. Combined.

Recommendation for raising of heifers

• Moderate raising +15% of intensity

• („physiological” intensity);

• New guideline:

gain of 1000-1200 g/day and

insemination at age of 12-13 months.

Benefits: economical (higher milk yield, shorter genetic interval)

Arguments for the more intensive

raising

• Role of of the fat tissue in the metabolism of sexual steroids

• The first lactation, it will be better

• Less need for replacement heifer in a year

Against:

- Shorter longevity

- Dystocia (difficult calving)

Control of the intensity of raising of heifers

Energy requirement: NEm, NEg,

Protein requirement: MP

(maintenance + gain)

Energy:protein ratio

Positive protein balance:

(negative UFP);

surplus of urea is harmful for the sexual organs

Feeding of heifers in practice

The most frequrnt ingredients of daiy rations for

dairy heifers:

Roughages: hays, maize stalk, silages, pasture grass;

Concentrates: small quantity (cereals, legume seeds)

NPN-supplement: in the case positive UFP

Nutrition of dairy heifers (cont.)

Feeding of concentrate: lower VFA in blood

(9 mg/l),

especially propionate: gluconeogenesis in liver;

- high blood glucose level (C3 in liver: glucose: glycogen;

lactic acid: cronic, slight acidosis.

Feeding of roughages:

higher volatile fatty acid (VFA) concentration in the blood (13 mg/l), especially acetate (C2).

Question-group II/a: feeding and nutrition of species

II/A/15. Feeding and Nutrition of Dairy Cows.

II/A/16. Feeding and Nutrition of Dry Cows.

(see also the material included in the handout of practical

about nutrition and feeding dry cows)

Life cycle of the dairy cows

• Calving interval:

- 365 days (first calving: 400 days);

- 305 days of lactation + 60 days of drying-off

Conditions:

- successful insemination on the 85th day of

lactation (between 60 and 90 days at a herd scale)

Anabolic and catabolic cycles of dairy cow

Lactation

Lactation

Drying-off

Insemination

Calving

Improvement

of condition

AnabolismCatabolism

Life cycle of the dairy cows (cont.)

3 periods

Period 1 (early lactation): mobilization of body tissues: decrease of BW (optimal BCS: 3.5);

Period 2 (mid- and late lactation): covering of nutrients released from milk

(for 1 kg of BW gain to supply a surplus of 26.8 MJ NEl and 276 g MP);

Period 3 (drying-off): syndrome of „thin” and „fat” cow.

Metabolism and regulation of milk

production

Homeostasis:

maintenance of physiological balance,

different distribution of nutrients.

Metabolism and regulation of milk production

(cont.)

Homeorhesis:

harmonized metabolic changes on tissue level, „redistribution” of nutrients.

During lactation:

- growth hormonal (GH) regulation;

- increase of milk production and of lypolitical activity,

- synthesis of glucose in liver, nutrient uptake of mammary gland.

Examples: elephant seals, polar bears

Body condition scoring of dairy cows

• It reflects the changes of body composition

more precisely than weighing of BW

Times of scoring:

1. After calving;

2. In the first 100 days of lactation,

3. After the 200th day of lactation;

4. At drying-off;

5. During drying-off.

Scores of Scores of Diff. Correction Final

tail head hook scores

4.0 2.5 1.5 - 0.5 3.5

1.5 2.5 1.0 + 0.5 2.0

3.0 2.5 0.5 - 3.0

Calculation of body condition scores

Changes of milk production, dry matter intake and weight gain during lactation

Milk production, kg

Drying-off Calving Months

Feed intake,

DM kg

Stages of lactation and gestation

1. Early lactation: 0 to 70 days (peak milk production) after calving (postpartum).

2. Peak DM intake: 70 to 140 days (declining milk production) postpartum.

3. Mid- and late lactation: 140 to 305 days (declining milk production) postpartum.

4. Dry period: 60 to 14 days before the next lactation.

5. Transition or close-up period: 14 days before parturition.

Early lactation

1. Feed intake:

a. energy (but too much grain may cause acidosis);

b. protein (ca. 20% in the daily ration)

c. crude fiber (min. 18% in DM).

Occuring problems:

a. Milk production: low peak production→ ketosis

low lactation production

b. Feed intake: too much grain fed too rapidly

off-fed, acidosis, dislocation of abomasum

Early lactation (cont.)

Practical tools to increase feed intake:

- top quality forage,

- diets contain adequate amounts of CP, DIP and UDP,

- increase of grain intake at a constant rate,

- adding fat (0.45 to 0.7 kg/cow/day),

- constant access to feed,

- minimizing of stress condiditons.

Second 10 weeks postpartum

Goals:

- to reach peak DM intake,

- to maintain peak lactation,

- no longer losing body weight.

Optimal daily ration:

- Grain intake (max 2.5% of BW)

- Good qality forage (highly digestible fibre)

- Non-fiber carbohydrate (max. 40%)

Mid- to late lactation (104 to 305 days postpartum)

1. Milk production (8 to 10% drop per month)

2. Early gestation period

3. Feed intake:

a. to meet milk yield requirement

b. to gain BW (to avoid over-conditioning!)

c. NPN-sources necessary?

Nutrition of dairy cows

According to the changes in the lactation

curve.

Problems during lactation:

- dry matter intake,

- energy balance,

- changes of body weight.

Results of negative energy balance

Change of body weight :

- decrease of 1 kg releases 20.60 MJ NEl

and 138 g MP;

- dominance of GH and ACTH.

Prerequisites of successful insemination:

- stopping of decrease of BW

- dominance of gonadotropic hormon and insulin.

Nitrogen balance

• In the beginning of lactation: negative

• After the first 100 days of lactation and

during pregnancy: anabolism

Guideline in the lactation phases 1, 2 and 3

1. Protein: 18-19% CP in DM;

35-40% UIP and ca. 30% in CP in early and in late

lactation, resp.

2. 7.8 MJ NEl per kg DM in early lactation, 6.6 MJ

NEl per kg DM in early lactation and 5.5 MJ NEl

per kg DM in dry period;

3. Forage amount (40% (min. 30%), 50% and 60% in

DM); crude fibre min. 20%;

4. Salt. 0.5% in DM

5. Mineral: Ca and P (1% of grain);

6. Vitamins: A, D and E (according to

requirement);

7. Ration form: forages and grains not to be

chopped or ground too fine

Guideline in the lactation phases 1, 2 and 3 (cont.)

Dry period of 60 to 14 days before calving

Goals:

1. High milk yield in the next lactation,

2. To mimimize metabolic problems.

Turnover of Ca and P

1. The higher input of Ca during drying-off,

the higher rate of absoption;

2. Decrease of secretion of parathormon;

3. Vitamin D3 is activated;

4. Activating capacity is hindered because of the

high level of Ca,

5. Ca-binding protein (CaBP) is not synthesised at

the optimal level.

Turnover of Ca and P (cont.)

• At calving: lower ratio of Ca and P

→ surplus of P decreases the activation of

vitamin D and atypical parturient parhesis;

Requirement during drying-off period

for 100 kg BW :

6.1 g Ca and 4.2 g P for maintenance and foetus.

Cation-anion balance:

[(Na + K)] - [(Cl + S)] /100 g dry matter;

Acidic chlorides and sulphates reduces occurance of parturient

parhesis.

Requirements of Ca and P

• For 1000 kg live weight:

44 g Ca,

34 g P.

• For 1 kg milk:

2.8 g Ca,

1.7 g P.

Inorganic Ca-supplement have better availability (depending also on age).

P-deficiency can cause alimentary sterility!

How to prevent and control milk fever?

• Review of the homeostatic/homeorrhetic

control of Ca-metabolism in ruminants

• Significance of Ca-intake in the dry period

• Significance of cation-anion-balance (CAB) in

the dry period

Mineral requirement of dairy cows

Mg: 2.0 g/kg DM for dairy cow

1.6 g/kg DM for dried-off and for heifer

Na, K, Cl: 0.63 g/kg milk, not limiting

Na:K ratio: effect on ovary if K is 10× higher

Zn: deficiency, decreases the rate of conception

Mn: function of ovary

Cu: disturbances in oestrus and conception

I: decrease of the intensity of metabolism

Mineral deficiencies and dairy cow diseases

• Mineral infertility mastitis lameness and others:

• Calcium: milk fever, retained cleansing, whites,low DMI (dry matter intake), dispaced abomasum, low milk yield.

• Phosphorus: milk fever, retained cleansing,fertility problems, lower milk yield, low DMI.

• Sodium: milk fever, udder oedema especially in heifers, not optimal rumen functions, laminitis, lower milk yield.

• Potassium: milk fever, low DMI.

• Magnesium: milk fever, grass staggers,low DMI.

Mineral deficiencies and dairy cow diseases (cont.)

• Copper: retained cleansing,

reproduction, immune system, bone formation,

nervous system.

• Zinc: reproduction, hormones, ceratin production.

immune system, horn quality, rumen function.

• Selenium: reproduction, retained cleansing, immune

system, joint laminitis, muscular dystrophy in calves.

Vitamine deficiencies and dairy cow diseases

Vitamin A: reproduction,retained cleansin, immune system, growth and development, calf mortality.

Vitamin D: bone diseases, linked to calcium and phosphorus, milk fever.

Vitamin E: reproduction, retained cleansing, immune system, laminitis, linked to selenium.

Requirement of vitamines and minerals

Vitamin E: mastitis;

Vitamin A, carotine: reproduction disturbances;

Vitamin A: nidation of ovum;

ß-carotine: protection against peroxides in ovary,

production of progesteron, fertility cycle;

(Deficiency of P and Zn: unsatisfying turnover of

Vitamin A and ß-carotine);

Vitamins B: B1- in the first 100 days of lactation,

niacin: 6-8 g/day, def. of B12 :Co-supply.

Balance of minerals and vitamins

• Homeostatis of minerals:

1. Modification of absorption, surplus of Ca is getting absorbed at a lower rate,

Fe, Zn, Mn are absorbed at a different rate;

2. Regulation by excretion in urine: Mg, F, Se, I, Na, Cl;

3. Changes in milk according to the supply: I and Mo;

4. Storing in tissues: Fe, Cu, F, Ca, Mo;

5. Endogenous excretion. Mn;

6. Sweating: Na;

7. Salivation: Na.

Ration formulation I: requirements

- See recommendations, like NRC, ARC, DLG,

INRA

- prediction of dry matter intake

- energy and protein (degradability)

- crude fibre, NSC (non-starch-carbohydrates)

-Ca, P, S, NaCl

- vitamin A, beta-carotene and vitamin D

Ration formulation: feeding systems

A Grazing (‘buffering’ by straw, hay or silage)

B Basal ration + milking concentrate

C Flate-rate feeding: silage ad libitum, amount of

concentrate in different periods of lactation is

the same

D TMR or total mixed ration: ratio of forage and

concentrate (in DM basis), adjusted to the

lactational phase: 40/60, 50/50, 60/40

assure minimum roughage needs (2-4 kg hay)

Ration formulation: practical ‘tricks’

- consideration of fulfilment unit

- enhance of dry matter intake

- use of buffers in feed of fresh cow

- use of protected amino acids (Met, Met+Lys)

- use liver protection (nicotinic acid, choline)

- add extra vitamin E and selenium (dry period)

- apply vitamin D during dry period

- if required: use acidifier (e.g. NH4Cl) (dry period)