Regulation of Feed Intake in Transition Cows

Barry Bradford

Associate ProfessorKansas State University

135 Call Hall, Manhattan, KS 66506bbradfor@ksu.edu

1-785-532-7974

Typical Transition Cow Goals

• Avoid transition disorders• Promote a steady rise in feed intake and milk

production to meet peak lactation goals• Set the stage for reproductive success

• Key to all of these: Minimize time and degree of negative energy balance

Promoting energy intake

Energy intake =

dry matter intake X energy density• Management• Carbohydrate profile• Bioactive nutrients

• Nutrient profile

• Liver is “hard-wired” to brain feeding centers via vagus nerve

• Great variation in pattern of oxidation of fuels over the short-term

• Feed intake is affected by pattern of oxidation

• Goal: maximize the amount of glucose produced per unit of ATP generated in the liver over time

Hepatic Oxidation Theory (HOT)

What are “hot” and “cold” diets?

• Hot = highly fermentable– Highly digestible forage sources– Relatively high concentrate levels– Some substitution of forage with nonforage fiber sources

(byproducts)

• Cold = less fermentable– Higher forage concentrations– Some poorly digestible forage (i.e. straw)– Resistant starch and/or nonforage fiber replaces some

processed starch

HOT Diet

Maximal milk yield

Satiety

Peak lactation cow

COLD DietMilk yield constrainedby nutrient supply

Satiety

Peak lactation cow

What about the transition cow?

Fat mobilization

Triglycerides (TG)

Oxidized orStored as TG

Fatty Acids(NEFA)

OxidizedMilk Fat TG

Liver Muscle

Adipocytes

Mammary

lipolysis, lipogenesis

Depressed feed intake during the transition period

hepatic oxidation

feed intake

plasma glucose

plasma insulin

NEFA

Can limiting NEFA release preventing DMI depression?

• Fed 24 g/d rumen-protected niacin• Close-up ration:

– 35% NFC, 42% NDF, 1.55 Mcal NEL / kg DM• Fresh cow ration:

– 40% NFC, 32% NDF, 1.69 Mcal NEL / kg DM• Treatments from 21 days before calving

to 21 DIM

Morey et al., 2011

Encapsulated niacin decreased plasma NEFA

-30 -20 -10 00

200

400

600

800

1000

1200

1400

1600

1800

Plas

ma

NEF

A (µ

M)

SEM = 82

Parity: P = 0.02

0 5 10 15 20 25

Control heifers

EN heifers

Control cows

EN cows

SEM = 216

Trt x time x parity:P = 0.09

Day relative to calving

Morey et al., 2011

-25 -20 -15 -10 -5 00

2

4

6

8

10

12

14

16

18

Dry

matt

er in

take

(kg

/ d)

SEM = 1.4

Trt x time x parity:P = 0.07

Niacin did not increase DMI

0 5 10 15 20 25

Control heifers

EN heifers

Control cows

EN cows

SEM = 1.7

Parity: P < 0.01Time: P < 0.01

Day relative to calving

Morey et al., 2011

Niacin has NEFA-independent effects

Titgemeyer et al., 2011

lipolysis, lipogenesis

Depressed feed intake during the transition period

hepatic oxidation

feed intake

plasma glucose

plasma insulin

NEFA

+ Propionate

- Propionate

Propionate has dual effects in early lactation

• Experimental infusion of propionate for 72 hours in early lactation decreased feed intake by 10% compared to acetate infusion

• This response was the most dramatic in cows with high blood NEFA concentrations

Stocks and Allen, 2010, 2011

How much starch in early lactation?

• Diets were based on corn silage (35%) and alfalfa silage (11.5%) and included 4% wheat straw

• Corn meal, soy hulls, and wheat midds were varied

Table 1. Dietary treatments 1 – 21 DIM 22 – 91 DIM Low (LL) 21% Starch 21% Starch

Medium/High (MH) 23% Starch 26% Starch

High (HH) 26% Starch 26% Starch

Nelson et al., 2011

High starch diet limited DMI

15

17

19

21

23

25

27

29

0 5 10 15

DM

I, k

g/d

Week Relative to Parturition

LL

MH

HHTrt: P = 0.06Time: P < 0.001Trt x Time: P = 0.09LL > HH: P ≤ 0.10

Nelson et al., 2011

Courtesy of H. M. Dann

n = 78 (total)

202530354045505560

0 5 10 15

Milk

, kg

/d

Week Relative to Parturition

LL

MH

HH

…and milk yield

Nelson et al., 2011

Courtesy of H. M. Dann

Trt: P = 0.04Time: P < 0.001Trt x Time: P = 0.75MH > HH: P ≤ 0.05

n = 78 (total)

Moderate starch delayed NEFA normalization

Nelson et al., 2011

Courtesy of H. M. Dann

n = 78 (total)

What about sugar?

• Sucrose was used to replace cracked corn grain at 4.7% of diet dry matter

• Diets were approximately 34% NDF, 34% NFC– 20.5 vs. 18.5% starch– 4.5 vs. 8.7% water-soluble sugars

• Fed for first 28 days in milk

Penner and Oba, 2009

Dietary sucrose increased DMI, ECM

DMI, kg/d ECM, kg/d0

5

10

15

20

25

30

35

40

Control5% Sucrose

P = 0.04

P = 0.09

Penner and Oba, 2009

Over the first28 days in milk

n = 52 (total)

Dietary sucrose in transition diets

• Sucrose did not alter energy balance• Sucrose decreased plasma glucose and

increased NEFA and BHBA concentrations• Increased ruminal pH (6.06 vs. 6.21, P = 0.08)• Increased total-tract OM digestibility, not NDF• Increased ruminal NDF digestibility and

passage?

Penner and Oba, 2009

Fat in peak lactation?

• Cows were fed a common diet for first 21 DIM, then randomly assigned to 1 of 4 diets:

• 60:40 forage:concentrate– 2.9% fatty acids– 5.0% fatty acids (prilled hydrogenated fatty acids)

• 40:60 forage:concentrate– 3.4% fatty acids– 5.5% fatty acids (prilled hydrogenated fatty acids)

Weiss and Pinos-Rodriguez, 2009

Fat in peak lactation?

Weiss and Pinos-Rodriguez, 2009

n = 72 (total)

Fat in peak lactation?

Weiss and Pinos-Rodriguez, 2009

n = 72 (total)

Fat in peak lactation?

Weiss and Pinos-Rodriguez, 2009

n = 72 (total)

Fat in peak lactation?

Weiss and Pinos-Rodriguez, 2009

n = 72 (total)

Transition diet recommendations

• Goals: Decrease NEFA, maintain rumen fill

• Feed fiber with long ruminal retention time

• Target moderate starch fermentability to supply adequate propionate without rapid production in a meal

• Consider using a sugar source (4-5% of DM)

When to change to the peak diet?

• Ideally, change to peak-lactation diet when plasma NEFA and ketones decrease and intake is steadily increasing

• Practically, cows with steadily rising feed intake and milk yield may be ready to shift diets as early as 7 days in milk, or as late as 21 days in milk

Peak lactation

• Dry matter intake is limited by gut fill in most cows

• Additional energy in the form of starch or fat should not depress DMI (within reason)

• Additional energy can increase BOTH milk production and BCS

Conclusions

• Attempts to prevent negative energy balance in early lactation haven’t worked!

• More energy in = more milk, in most cases

• There is hope for improved feed intake, which generally improves transition performance

Thank you!