status of evaluation of three maternal lines under pasture ...€¦ · status of evaluation of...

Status of evaluation of three maternal lines

under pasture lambing experiment at USMARC

Easy Care

Katahdin

Polypay

Brad A. Freking

USDA, Agricultural Research Service,

U.S. Meat Animal Research Center,

Clay Center, NE

USDA is an equal opportunity provider and employer. February 1, 2018

Reducing labor per ewe is one of the best opportunities to increase

profitability and attract new investments to the industry.

One approach is to use “easy care” genetics

in a low-input, pasture-lambing production system.

Romanov provided the genetic foundation for ewes.

Identified breeds that complement Romanov germplasm.

The strategy was to create well-balanced levels

of prolificacy and maternal ability in Romanov

crossbred ewes to realize acceptable lamb survival.

Background for production system project

Desirable Ewes for Pasture Lambing

✓ eliminate shearing

✓ avoid docking tails

✓ have no horns to remove

✓ are genetically resistant to scrapie and OPP

✓ are genetically resistant to parasites

✓ have long breeding seasons

✓ raise twins and triplets on pasture unaided

✓ balance mothering ability and prolificacy

✓ transmit lamb behavior enhancing survival

✓ have a long productive life

Develop an easy-care maternal line of prolific hair sheep that

can raise triplets on pasture without labor or supplemental feed.

1/2 Romanov

1/4 Katahdin 1/4 White Dorper

Management Procedures during experiment

✓ 35 d mating season (multi-sire) during Dec.

Ewes assigned to PB or Terminal mating system for

entire experiment

✓ Lamb in groups of 100 ewes on 10 acre pastures in

May

✓ As little intervention as possible during lambing period

(cases of hypothermia are intervened)

✓ Tag lambs, castrate males and get blood sample after

lambing season over. Wean at ~ 70 d

✓ Genotype for parentage and line determination

Evaluation of ewe productivity through 4 parities

Year of evaluation

Birth year of

ewe 2014 2015 2016 2017 2018 2019

2013 x x x x

2014 x x x x

2015 x x x x

- Carcass trait data on 2016 and 2017 lambs

- Parity 5 lambing data in barns under cameras

Starts March 2018.

Additional Evaluations on these lines:

Mating system

Ewe Breed Purebred Terminal -Texel

Year ‘14 ‘15 ’16 ‘17 ‘14 ‘15 ’16 ‘17

Katahdin 65 122 156 145 65 120 155 134

Polypay 72 139 176 147 70 137 182 160

Easycare 70 134 191 162 71 128 179 156

Number of ewes exposed per breed and mating system

∑ = 3136

Statistical Models

EWE TRAITS LAMB TRAITS

Lambing Band

Maternal Line

Mating System

Age of Dam

2- way interactions

Sire of ewe (line)

Lambing Band

Sex

Maternal Line

Mating System

Age of Dam

Wean Family Size

2- way interactions

Sire of lamb (line)

Maternal

line

Mating

System

Ewes

Exposed

Lambs

born

(found ?)

per ewe

exposed

Lambs

weaned

per ewe

exposed

Lamb wean wt

per ewe

exposed, kg

Katahdin PB

TX

488

474

1.27

1.24

1.13

1.07

17.73

18.04

Polypay PB

TX

534

549

1.36

1.33

1.12

1.13

18.73

20.26

Easycare PB

TX

557

534

1.77

1.74

1.57

1.50

22.26

22.22

Productivity of Katahdin, Polypay, and Easycare ewes

in production system experiment in 2014-2017

P = 0.99 P = 0.22 P = 0.17

Co

ncep

tio

n r

ate

sProductivity of Katahdin, Polypay, and Easycare ewes


0.78

0.8

0.82

0.84

0.86

0.88

0.9

0.92

0.94

0.96

KT x KT KT x TX PO x PO PO x TX EZ x EZ EZ x TX

Maternal line by mating system P = 0.86

Co

ncep

tio

n r

ate



0.78

0.8

0.82

0.84

0.86

0.88

0.9

0.92

0.94

0.96

KT PO EZ

Maternal line P < 0.001

a

a

b

Co

ncep

tio

n r

ate



0.78

0.8

0.82

0.84

0.86

0.88

0.9

0.92

0.94

1 2 3 4

Age of Dam P < 0.001

a

b

b

b

Nu

mb

er

lam

bs b

orn

an

d

we

an

ed

/ e

we

exp

os

ed



0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


Maternal line by mating system P > 0.26

Nu

mb

er

lam

bs b

orn

an

d

we

an

ed

/ e

we

exp

os

ed



0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

KT PO EZ


ab

c

a a

b

Nu

mb

er

lam

bs b

orn

an

d

we

an

ed

/ e

we

exp

os

ed



0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1 2 3 4

Age of dam P < 0.001

a

b

c c

a

b

c c

Lam

b w

ean

wt

an

d 2

0

wk

wt

/ ew

e e

xp

osed

, kg



0

10

20

30

40

50

60

70

KT PO EZ


ab

c

a

b

c



0

10

20

30

40

50

60

70

1 2 3 4

Age of dam P < 0.001

Lam

b w

ean

wt

an

d 2

0

wk

wt

/ ew

e e

xp

osed

, kg

a

b

cc

a

bc c

Direct effects on lamb growth

In production system experiment in 2014-2017

0

10

20

30

40

50

60


Maternal line by mating system P = 0.12

P < 0.001

Lam

b w

ean

wt

an

d

20 w

kw

t, kg

a ab b

c c

Lam

b w

ean

wt,

kg

13

13.5

14

14.5

15

15.5

16

16.5

KT PO EZ




a

b

c

14.2

14.4

14.6

14.8

15

15.2

15.4

15.6

15.8

PB TX

Mating System P < 0.001

Lam

b w

ean

wt,

kg



a

b

14.8

14.9

15

15.1

15.2

15.3

15.4

15.5

MALE FEMALE

Sex of lamb P < 0.001

Lam

b w

ean

wt,

kg



a

b

Lam

b w

ean

wt,

kg

0

2

4

6

8

10

12

14

16

18

20

SINGLE TWIN TRIPLET

WEAN FAMILY SIZE P < 0.001



a

b

c

Maternal

line

Mating

System

Triplet

sets

born

Triplet

sets

weaned

3

Triplet

sets

weaned

2

Triplet

sets

weaned

1

Triplet

sets

weaned

0

Katahdin PB

TX

5

1

3

0

2

1

0

0

0

0

Polypay PB

TX

6

9

0

4

5

3

1

1

0

1

Easycare PB

TX

37

32

17

11

16

15

3

5

1

1

FREQ of triplet lambs in production system

experiment in 2014-2017

3% of ewes raised 0 lambs.

10% of ewes raised 1 lamb.



211 sets of triplets were born to 2- and

3-year-old Romanov crossbred ewes.


11% of ewes raised 1 lamb.



69 sets of triplets were born to EZ ewes

Summary

▪ Utilizing appropriate genetics resources for

increased reproduction under low input

management systems is attainable, letting these

ewes rear triplets !

▪ Utilizing both maternal and individual lamb

heterosis is the most important aspect of increasing

reproductive performance

▪ Further evaluation of lamb growth carcass merit

along with maternal/lamb behavior in parity 5 and

ewe longevity data to complete experiment

▪ Plans for selection experiment within EZ population

for tolerance to parasites

status of evaluation of three maternal lines under pasture ...€¦ · status of evaluation of...

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