Reproductive Management in Beef Cattle Estrous Synchronization and AI Richard F. Randle, DVM, MS Beef Extension Veterinarian University of Nebraska, Lincoln

U.S. Beef Cattle Inventory 2007 Census of Agriculture Farms Cattle Farms with No. % of Total 1 to 49 607,708 79 9,413,294 29 50 to 99 84,253 11 5,656,207 17 100 to 499 67,210 9 12,475,448 38 500 to 999 4,413 0.5 2,861,202 1000 + 1,400 0.2 2,428,650 7 Total 764,984 100 32,834,801

The U.S. Beef Herd 69% of cow-calf enterprises are secondary income sources 50% of producers report an established breeding season of specific duration 34% of beef herds are routinely pregnancy checked 10% of beef cattle enterprises utilize AI From NAHMS Survey, 1998

Reasons for not Using Reproductive Procedures From NAHMS Survey, 1998

Meeting the Demand? Having the correct genetics is becoming highly important to meeting industry demands Correct genetics imperative to achieving premium dollars and enhancing returns on investment

A changing market structure that recognizes and rewards quality . . . AI allows beef producers to use high accuracy proven sires … BW and calving ease Weaning and yearling growth Carcass traits Replacement females

AI provides the opportunity to make genetic progress and add value faster

Effective Estrus Synchronization Programs Shorten the AI breeding season Cows or heifers are in estrus during a predictable interval that facilitates AI Reduce time and labor required to detect estrus More cows and heifers becoming pregnant early during the breeding season Result in older and heavier calves at weaning Beneficial effects on the next breeding season More days postpartum at the next breeding season Replacement heifers will be older The first question you may ask is what will estrus synchronization do for me? Effective synchronization programs will shorten the AI breeding season. Synchronized animals exhibit estrus at a predictable interval that facilitates AI thereby reducing time and labor required to detect estrus. More animals conceive early in the breeding season. This results in older, heavier calves at weaning. An additional benefit is the effects on the following breeding season. Animals conceiving early in the current breeding season have more days postpartum to prepare for rebreeding in the next season.

Improvements in methods to synchronize estrus create the opportunity to significantly expand the use of AI in the U.S. cowherd...

Estrous Cycle Length of the estrous cycle Average 21 days (range 18 to 24 days) Estrus (standing heat) 12 to 18 hours (range 8 to 30 hours) Ovulation Approximately 30 hours after the beginning of standing heat.

LH level LH surge onset of heat Progesterone Estradiol Luteal 2 4 6 8 10 12 14 16 18 20 20/0 Progesterone Day of cycle *Two full cycles and start of a third Estradiol Luteal Follicular

LH level LH surge onset of heat Progesterone CL Estradiol Follicular 2 4 6 8 10 12 14 16 18 20 20/0 Progesterone Day of cycle *Two full cycles and start of a third CL Estradiol Follicular Luteal Follicular Luteal

Corpus Luteum (CL) Growth and Regression 2 4 6 8 10 12 14 16 18 20 Estrus Day of the Estrous Cycle Growth Regression Ovulation

Day of the Estrous Cycle Prostaglandin F2 2 4 6 8 10 12 14 16 18 20 Day of the Estrous Cycle PG regresses CL NO YES Estrus

Follicle Development Follicular Wave Dominance Regression Growth Selection Next Recruitment Recruitment Follicle development occurs as a wave-like pattern consisting of “Recruitment”, “Selection”, “Growth”, “Dominance”, and “Regression” phases. Usually 2 to 4 follicular waves occur during the estrous cycle in cattle

Typical Pattern of Follicular Growth in Lactating Dairy Cows

Day of the Estrous Cycle Follicle Development During the Estrous Cycle Example for 2 Follicular Waves Day of the Estrous Cycle 2 4 6 8 10 12 14 16 18 20 Estrus Ovulation Length of the estrous cycle in cattle with 2 follicular waves is typically 18 to 20 days, slightly shorter than the estrous cycle with 3 follicular waves

LH level LH surge onset of heat Progesterone Estradiol Follicular 2 4 6 8 10 12 14 16 18 20 20/0 Progesterone Day of cycle *Two full cycles and start of a third Estradiol Follicular Luteal Follicular Luteal

GnRH Induces ovulation Synchronizes follicular waves Induces formation of a CL

How Does GnRH Induce Ovulation? GnRH, LH surge, and Ovulation GnRH Injection 2 to 4 Hours after GnRH injection 24 to 30 Ovulation LH Surge GnRH induces LH surge within 2 to 4 hours If cattle have large, healthy follicles, ovulation will be induced approximately 24 to 30 hours after GnRH injection without estrous behavior

How Does GnRH Induce Ovulation How Does GnRH Induce Ovulation? Relationship between Follicular Waves and GnRH NO YES GnRH injection can induce ovulation in large, healthy follicles more than 10 mm in diameter GnRH injection cannot induce ovulation in smaller follicles, less than 10 mm in diameter (premature) and regressing follicles (aged and not healthy) Diameter of follicles are based on the data from ultrasonographic examination > 10 mm

LH level LH surge onset of heat Progesterone Estradiol Follicular 2 4 6 8 10 12 14 16 18 20 20/0 Progesterone Day of cycle *Two full cycles and start of a third Estradiol Follicular Luteal Follicular Luteal

Effect of a Progestin Heat Detect System Estrus Response Synch Preg Rate 2-shot PG 241/452 = 57% 147/422 = 35% --------------------------------- MGA-PG 17 d 305/408 = 75% 220/408 = 54% MGA-2 shot PG 327/348 = 93% 243/348 = 70% MGA-PG 19d 161/208 = 78% 130/206 = 63% MGA Select 275/313 = 88% 195/313 = 62% 7-11 Synch 142/155 = 93% 101/155 = 65% Inclusion of a progestin can induce approximately 50% of non-cycling animals to cycle.

Effective Synchronization Physiology and Biology Synchronization of follicular waves Induction of ovulation Management of the CL lifespan Initiation of estrous cyclicity

Effective Synchronization Effective Products Available GnRH Cystorelin®, Factrel®, Fertagyl®, OvaCyst® Prostaglandin Estrumate®, In-Synch®, Lutalyse®, Prostamate® Progestogens MGA®, Eazi-Breed CIDR®

Resurgence in Research on Estrus Synchronization

Resurgence in Research on Estrus Synchronization Ultimate goal is fixed-time AI with acceptable pregnancy rate!

Applied Reproductive Strategies in Beef Cattle Beef Reproduction Task Force http://beefrepro.unl.edu

Beef Reproduction Task Force Review of the literature Comparison of protocols Beef Heifers Heat detection protocols Heat detection + timed AI protocols Fixed-time AI protocols Beef Cows

Comparison of Protocols Cows Pregnancy Rateb Heat Detection Reportsa No. of Cows Range Average Select Synch 4 678 38-70 46 Select Synch + CIDR 8 595 42-85 51 Heat Detect &TAI 6 2048 31-89 1596 36-77 56 Fixed-Time AI CO-Synch + CIDR 15 8124 43-80 59 aNumber of reports in published literature bNumber pregnant to AI/total number treated

Comparison of Protocols Heifers Pregnancy Rateb Heat Detection Reportsa No. of Heifers Range Average 1 Shot PG 1(18 herds) 2700 ------ 45 CIDR-PG 1 147 41-49 51 CIDR-PG (heat detect 3 d) 2 745 33-61 46 MGA-PG 6 2746 40-71 60 Heat Detect &TAI Select Synch + CIDR 748 31-67 56 5 1905 48-64 Fixed-Time AI CO-Synch + CIDR 10 1389 24-68 49 831 36-62 CIDR-Select 1069c 26-78 61 aNumber of reports in published literature bNumber pregnant to AI/total number treated cField data from 13 herds

Synchronization and Natural Service Use a protocol that uses heat detection Use smaller breeding pastures or lots to reduce travel Use young mature bulls that are active known breeders Make sure pecking order is established Use bull to female ratio of 1:15 to 1:25

Synchronization and Natural Service 5 45 Natural Service PG 1 Shot- PG Treatment day Bulls in Non-synchronized Synchronized P-value n 2075 521 Calf birth date, julian day 86 85 0.23 Calf birth wt., lb 84 81 <0.001 Calved in 1st 21 days, % 61 73 Pregnant, % 95 94 0.48 Weaning wt., lb 483 503 Larson DM, Musgrave JA, Funston RN, University of Nebraska

Estrus Synchronization: Planning for Success

Plan the work. Work the plan! Expectations for synchronization protocol. Is the herd suited for synchronization protocol? Labor needs . Number of time through the chute. Synchronization costs. Handling facility capabilities. Impact on calving distribution. Record system.

Synchronization Expectations Survey of recent results from today’s mainstay protocols 10 trials with 2,970 females from 34 different experimental groups Average Synch preg. rate = 50.5% (8 to 66%) 26% of groups > 60% synch preg. rate 50% of groups 40% to 60% synch preg.rate 24% of groups < 40% synch preg. rate

Synchronization Expectations Survey of recent results from today’s mainstay protocols 10 trials with 2,970 females from 34 different experimental groups Average Synch preg. rate = 50.5% (8 to 66%) 26% of groups > 60% synch preg. rate 50% of groups 40% to 60% synch preg.rate 24% of groups < 40% synch preg. rate Don’t expect great miracles. Do expect variation.

Conception Rate Formula (Cow fertility) X (Heat detection) X (Semen fertility) X (AI technique) Fail at any one of these and kiss success goodbye!!

Heat Detection Protocols Heat Detection Rate 55% 60% 65% 70% 75% 80% 85% 90% 95% Conception Rate Pregnancy Rate 39% 42% 46% 49% 53% 56% 63% 67%

% of Cows Exhibiting Standing Estrus Time of Day % of Cows Exhibiting Standing Estrus 6am to noon 26.0% Noon to 6pm 18.1% 6pm to midnight 26.9% Midnight to 6am 29% Perry, GA: South Dakota State University

Estrous Detection

Estrous Detection Detection aides Kmars Chinball markers Gomer bulls Tail chalk HeatWatch

Synchronization is an Investment Labor Facilities Management Dollars In round numbers Budgeted costs for synch programs can range from $20 to $40 per synchronized female

Is the Herd a Good Candidate? Fertility rate Calving distribution Cow age Body condition Calving success Replacement management

Replacement Management Target Weight Reproductive tract scores Breed 20 days prior to cows

Cow Age Heifers take 20 days longer to cycle… Johnson and Stevenson, KSU

Calving Distribution

Body Condition Score CS = 4 CS = 6 Daryl Strohbehn, Iowa Beef Center

Body Condition Score CS = 4 CS = 6 A Barometer of the Nutrition Program CS = 4 CS = 6 Major Influence on Start of Cyclicity Daryl Strohbehn, Iowa Beef Center

Effect of BCS at Breeding on % Cycling 25% CS 4-4.5 40-48% CS 5-5.5 58-72% CS 6 80% or more Daryl Strohbehn, Iowa Beef Center

Effect of Body Condition Score at Calving on Postpartum Interval 100 80 60 Days Postpartum 88.5 40 69.7 59.4 20 51.7 30.6 3 4 5 6 7 Body Condition Score (BCS) Adapted from Houghton et al., 1986

Labor Needs Labor centers around feeding schedules, cattle roundup and handling through chute, heat detection, and AI schedules. Shortage of labor at key times during the program poses critical threat to success. Many times breeding programs compete with other farming routines.

Number of trips through the chute… varies with the synchronization protocol From IBC Estrus Synch Planner 2004

Cattle Handling Facility A good facility is a necessity for a successful synchronized AI program Think about cattle flow and efficiency Think about safety Think about location

Cattle Handling Facility Location Often located near wintering/calving facilities and nowhere near breeding pastures Need to think about cattle management flow prior to synch program May mean short dry lot periods or changes in pasture rotations

Do we know what to expect at calving from cows that conceive on the same day to the same sire?

Days relative to 285 d gestation due date; Bader et al., 2004 5 10 15 20 25 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 6 7 8 5 10 15 20 25 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 A; Angus; +6.2 BW 272-292, 20 d B; Angus; +3.3 BW 275-292, 17 d 5 10 15 20 25 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 10 15 20 25 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 6 7 8 9 C; Red Angus; –1.5 BW, 2 CED 274-289, 15 d D; Simmental; -0.6 BW, +14.8 CE 275-294, 19 d 25 B; Angus; +3.3 BW 274-291, 17 d 20 15 % of AI calves born 10 5 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 Days relative to 285 d gestation due date; Bader et al., 2004

Summary For best success: Current herd fertility >90% in 60-90 day breeding season Best female candidates calve in 1st 42 days of breeding season, thus at least 40 days before start of breeding season 1st calf heifers need additional recovery time following calving Cows need minimum body condition score of 5

Protocol Compliance PGF MGA CIDR GnRH Numerous systems Each with unique twist

Common Causes for Poor Results Wrong system for the situation More anestrous animals than expected Cow protocol applied to heifers Protocol not followed Scheduling errors in timing of feed supplements and/or injections Wrong product given

AMDUCA Animal Medicinal Drug Use Clarification Act Defines extra-label drug use (ELDU) Prostaglandin YES Progestins YES GnRH NO

Successful synchronization and AI programs require careful planning and attention to detail!