Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 1

The Postpartum Interval: Management of Anestrus

Management of Anestrus in Cattle

1. What is anestrus and is it a problem?

2. What factors influence the duration of anestrus?

3. How is anestrus managed?

Anestrus•Definition: Females that are not exhibiting estrous cycles

•Anestrus occurs annually; heifers are anestrus prior to puberty and anestrus occurs in cows after each calving.

•The anestrous period in postpartum cows ranges from 14-180 days in length.

üFor mature cows, 30-90 days is normal.üFor young cows (2 year olds), 60-120 days is normal.

Postpartum Anestrus in Beef Cows

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

Stru

ctur

e D

iam

eter

Days Relative to CalvingCalving First

Estrus

Progesterone

* *

Anestrus45 to 90+ days in US Beef Cows

1st DFHypothalamus restrained

Uterineinvolution

-55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 60 65 70 75

“Depth” of Postpartum Anestrus in Beef Cows

Hor

mon

e Co

ncen

tratio

n

Days Relative to First Estrus First Estrus

Progesterone

Peri-Estrus

Anestrus

Increasing “Depth” of Anestrus

Estrogen inhibitory! Estrogen stimulatory!

Incidence of Anestrus in US Beef Cattle

0

10

20

30

40

50

60

Postpartum Cows Yearli ng He ifers

Lucy et al., 2001

% C

yclic

Fem

ales

Range 33 -83%

Range 19 -94%

14.7 mo of age

851 cows at 6

locations

56 days postpartum

724 heifers 5 locations

Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 2

Anestrus in US Beef Cattle

55

64

0

10

20

30

40

50

60

70

Parit y 1 Parit y 2+

Stevenson et al., 2003

% C

yclic

Fem

ales

68 days postpartum

673 cows

86 days postpartum

2,547 cows

35

47 45

6861

0

15

30

45

60

75

1994 1995 1996 1997 1999

Year

% o

f al

l co

ws

% Cyclic

Percent of Cows Cyclic by Year (~ 60 d postpartum)

(Jackson Branch of the OSU Ag Experiment Station, Jackson, OH)

Reproductive Classes Within the Cow Herd

Random stages ofthe cycle

AnestrousCows

Deep Anestrous

Shallow Anestrous Cyclic

Cows

50%50%

Factors Regulating the Length of Anestrus

•Presence of the calf• Initiates anestrus

•Body Condition Score (BCS)•Parity•Days Since Calving•Others effectors include dystocia, health, and calving season

Presence of the Calf

•Presence of the calf initiates anestrus•Establishes the restraint on the hypothalamus.•Mechanism unknown but both the physical contact of the calf

(nursing) and the mere presence of the calf at side are involved.

•Short-term calf removal (48 h) has been shown to be an effective method to induce estrus.

BCS

Ribs visible, sharp bones Smooth, no visible ribs or bone structures, fat deposits on tail head, brisket

3 6

Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 3

Nutrients

Energy

Life

Estrous Cycles

Activity

Base Fat Reserves Growth

Pregnancy

Lactation

Added energy

Mature Cows Two Year Olds

Influence of BCS on Anestrus80

7159

49

2542

0%

20%

40%

60%

80%

100%

<3.5 4 4.5 5 5.5 >6

Body Condition Score

% C

yclin

g

3371,002726481157 188

Source: Stevenson et al., 2003

BCS and Reproduction – Mature Cows

CalvingBCS < 4 5 > 6

Number of Cows 122 300 619

Pregnancy Rate 58 85 95

BCS and Reproduction - Young Cows

Preg Rate Days to Pregnancy BCS n % n days

4 73 65 47 92 5 157 71 100 82 6 120 87 96 74 7 73 91 61 76

BCS and Anestrus

BCS 3, Anestrus ~ 100-150 days

Pregnancy potential 0-30%

BCS 6, Anestrus 60-70 days

Pregnancy potential ~ 90%

Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 4

Influence of Days Since Calving on Anestrus

9

25

44 4555

6270

62

01020304050607080

<30 31-40 41-50 51-60 61-70 71-80 81-90 >90

Days Postpartum

% C

yclin

g

Source: Stevenson et al., 2003

JanAug Sep Oct Nov Dec DecJan Feb

Months

Impact of PPI, calving, and rebreeding

Gestating Cows

NovMar Apr May Jun Jul Aug Sep

Calving Season

Breeding Season

Oct

* ** *

**

* **

*

* *

Managing Anestrus

How do we mimic the transition?

•Can we induce estrus?•Give estrogen

•Induces estrus within 24-48 hours•CL is short-lived; fertility is very low

•Can we induce the LH surge?•Give LH/GnRH

•Mimics or induces LH surge•CL is short-lived; fertility is very low

How do we mimic the transition?•Can we mimic the short cycle?

•Administer a progestin•Progestin administration (>5 days) will induce an LH surge and

usually estrus within 72 hours•CL is typically normal•Fertility can be acceptable; 45-70%

•Products with progestin activity•MGA®

•EAZI-BREED CIDR® Cattle Inserts•GnRH

Induction of Estrus Using a CIDR or MGA

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

Folli

cle

Dia

met

er

Days Relative to CalvingCalving

CIDR or

MGA *

Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 5

ES and Natural Service

Turn in bulls

MGA or CIDR0 7 8

ESNS

Lamb et al, 2007

% Calved

First 30 d

Days to

ConceptionCalving Group n Preg %

Control 1034 88.6% 66.7% 23.2

916/1034 690/1034

CIDR 999 88.9% 68.2% 20.1

888/999 681/999

15 locations, 6 states, herd size 47-328, PPI 56.9, parity 4.3, BCS 5.5

Bull:cow ranged from 1:15-1:30.

ESNS

UK

Calving Group n Preg %% CalvedFirst 30 d

Control* 621 83 47

515/621 292/621

MGA* 614 93 78

193/215 172/215

Control** 419 84 45

392/419 188/419

CIDR** 421 91 80

383/421 336/421

*21 locations, conducted in 2004**16 locations, conducted in 2005Bull:cow ranged from 1:23-1:42. Ratio the same within a locationCows - BCS minimum 5 at calving, 14-103 days PP, 2-13 years of age

Return on Investment•108 cows; 54 MGA-Bull, 54 Corn-bull•15% increase in pregnancy rate (80 v 95)•40.4 extra pounds at weaning per calf (17 d older)

•Estimated return on investment:•Cost per cow = $2.96/cow for 7 days of MGA•Return per cow•31,110 lbs x $140 = $44,554/54 = $806.56•24,510 lbs x $140 = $34,314/54 = $635.44•$171.12 return per cow treated

Targeted

ESNS

% CalvedFirst 30 dCalving Group n Preg %

Early* 234 94 77

220/234 180/234

Late** 215 90 80

193/215 172/215

Primiparous 68 88 69

60/68 47/68

Very Late*** 66 88 71

58/66 47/66*Early-calving cows calved in the first 46 days**Late-calving cows calved in the last 45 days***Very late-calving cows calved 7-21 days from CIDR insertion

Very Late-Calving Cows

•Project of the last 5 years

•177 mature cows, minimum BCS 5, 19 locations•14-28 days postpartum•88% conceived•77% calved in first 30 days, calving date shifted 28 days

Les Anderson, University of Kentucky Aug. 20, 2019

2019 ARSBC, Knoxville, Tenn. 6

Inserted CIDR’s on May 14, 20132013 calving date 2014 calving date Days Earlier

1st calf heifer 4/13 3/5 39 days

1st calf heifer 4/27 3/26 31 daysCow 4/2 3/10 22 days

Cow 4/29 3/21 39 days

Inserted CIDR’s on June 17, 2013

1st calf heifer 5/26 4/7 49 daysCow 5/19 4/30 20 days

Cow 5/26 5/30 - 4 daysCow 5/31 4/8 52 days

7 of the 8 cows calved an average of 36 days earlier in 2014 compared to 2013. Additional 70 pounds of WW per calf for a total of 490 additional pounds X $140 (average price of steers and heifers weighing 500/550 pounds) = $686 return on a $88 investment.

Example Summary

•Anestrus is the major factor regulating reproductive efficiency.•Induction of estrus in anestrous cows is essential to maintaining a high reproductive rate.•Estrous synchronization protocols for anestrous females MUST include a progestin (CIDR, MGA, or GnRH).