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Ovine Observer

Marking more from Merinos

Beth Paganoni, Department of Agriculture and Food, Western Australia (DAFWA)
Email: Beth.Paganoni@agric.wa.gov.au

Andrew Thompson, Murdoch University

Claire Macleay, Department of Agriculture and Food, Western Australia

Steve Wainwright, University of Western Australia

Marking more from Merinos requires the marriage of astute management and carefully selected genetic direction. Our Maternal Efficiency Flock (MEF) is a research flock that has attempted to achieve both, in order to demonstrate the reproductive potential and economic viability of the Merino as a dual purpose, high-performing ewe. The MEF was established in 2009 when 300 cull ewes were purchased by the Department of Agriculture and Food, Western Australia (DAFWA) from two ram breeders in Western Australia. The flock was moved from a commercial property near Katanning to the University of Western Australia’s (UWA’s) Ridgefield Future Farm in January 2010. Each year the ewes have been mostly single-sire mated to industry sires and sires from within the MEF specifically selected for carcass traits (high post-weaning weight, eye muscle and fat depth) and ‘easy-care’ traits such a low wrinkle and high resistance to flystrike. The flock has never been mulesed.

All the progeny generated by these ewes and subsequent generations have been measured for feed efficiency and methane production at post-weaning age, and fat, muscle, liveweight, wool traits and reproduction across multiple ages. To our knowledge, the MEF is the only self-replacing sheep flock in the world with such comprehensive measurements of feed efficiency and methane. All the progeny are fully pedigreed and have Australian Sheep Breeding Values registered with Sheep Genetics Australia.

Table 1 The number of ewes born in 2011, 2012 and 2013 from the MEF that were naturally joined with single or syndicate sires in 2015, their mean joining weight, reproductive rate (percentage of lambs born to ewes joined) and marking rate (percentage of lambs marked to ewes joined), and the mean birth weight and growth rate to marking of their single and multiple-born lambs. (Number = n, kilograms = kg, grams per head per day = g/h/d). Note: all data means presented in the table are raw (that is, not analysed or adjusted for lamb sex, lambing paddock, date of birth, etc.)
Ewe year of birth Ewes joined (n) Ewe live weight at joining (kg)

Lambs born to ewes joined (%)

Lambs marked to ewes joined (%)

Birth weight singles (kg)

Birth weight multiples (kg)

Growth rate to marking singles (g/h/d)

Growth  rate to marking multiples (g/h/d)

2011 117 64.8 158 144 5.09 4.49 308 252
2012 347 63.8 135 121 5.52 4.74 316 259
2013 283 59.5 95 89 5.27 4.44 311 239
Table 2 The number, survival to marking (lambs marked as a percentage of lambs born), birth weight, marking weight and growth to marking, of single, twin and triplet-born lambs born in 2015 from the MEF. Note: all data means presented in the table are raw
Birth type Lambs born (n) Lambs marked to lambs born (%) Birth weight (kg) Marking weight (kg) Growth rate to marking (g/h/d)
1 338 94.4 5.36 15.3 312
2 600 89.0 4.63 13.4 253
3 36 61.1 4.07 13.2 24

Recent lamb marking results from the MEF show not only the high-performing potential of the Merino ewe, but also some of the variation in genetic potential of Merinos that we have measured for reproduction.

The research flock is maintained under commercial grazing conditions, all ewes are weighed monthly and scanned for litter size, and all lambs born are identified to dam, weighed and tagged at birth. Despite current recommendations for maximum reproduction, to meet ethical requirements ewes are joined in full wool and shorn during early pregnancy. The average age of adult ewes is three years. A unique management characteristic of the flock is that most of the adult ewes were joined as ewe lambs at seven to eight months of age.

In 2015, adult ewes were joined on 22 January and rams removed on 23 February. Weather conditions during lambing this year were above average, but feed on offer (FOO) was low, with <1000kg dry matter/hectare of FOO across all lambing paddocks. Adult ewes were 62kg and condition score 3.1 at joining, 65kg and condition score 3.5 in mid pregnancy, 67kg and condition score 2.9 at day pre-lambing.

In spite of tight feed conditions, ewes performed well with four year-old ewes marking 144% and three year-old ewes marking 121% lambs to ewes joined (Table 2). Two year-old ewes marked 90% lambs to ewes joined. This was their second joining experience as they were all joined as ewe lambs in 2014. In 2014 our ewe lambs marked 42% lambs to ewes joined, which also represents our typical marking response for ewe lambs in the project. Lamb growth rates to marking appeared to be higher for singles than multiples, but similar for lambs born to two, three or four-year old ewes (Table 2).

The survival and birth weights of single-born lambs were higher than multiple born lambs (Table 2). Only 12 ewes were recorded as having triplet lambs, and while their birth weights were lower than twin-born lambs, their marking weights were similar, indicating that only the heavier born triplet lambs survived to marking.

The majority of the adult ewes are joined to single-sires (approximately 50-60 ewes/sire), for the ease of recording sire pedigrees for lambs. As a result, we can look at the direct paternal genetics of the lambs born, and also the reproductive performance of ewes (dams) from different sires (grandsires of the lambs).

Table 3 The number of singles and multiples born, and the survival to marking (lambs marked as a percentage of lambs born), average birth weight and growth rate of single and multiple-born lambs from different sires. Note: all data means presented in the table are raw
Sire of lambs Singles born (n) Multiples born (n) Lambs marked to lambs born singles (%)

Lambs marked to lambs born multiples (%)

Birth weight singles (kg) Birth weight multiples (kg) Growth rate to marking singles (g/h/d) Growth rate to marking multiples (g/h/d)

13 301

33 77 94 79 5.1 4.3 309 233

13 327

33 64 94 100 5.8 4.6 312 245

13 169

29 108 90 92 5.1 4.4 325 251

13 198

15 102 87 80 5.5 4.9 312 276

13 298

27 129 96 79 5.6 4.8 319 262

13 329

26 121 96 77 5.4 4.3 301 241

13 484

23 136 100 83 4.8 4.3 304 240

13 212

24 92 92 89 5.0 4.6 307 239

13 326

26 96 100 75 5.9 5.1 327 271

14 501

36 114 97 73 5.6 4.9 313 253

14 502

16 85 100 74 6.0 4.9 315 268

14 503

20 114 85 75 5.0 4.2 309 241

14 504

26 89 96 81 5.1 4.4 317 273
Table 4 The number of ewes joined, their mean liveweight at joining and the marking rate (percentage of lambs marked to ewes joined) of ewes from sires from the MEF that had a minimum of 15 daughter ewes joined naturally in 2015, as well as the mean birth weight and growth rate to marking of their single and multiple-born lambs. Note: all data means presented in the table are raw
Sire of ewes Ewes joined (n) Ewes weight at joining (kg) Lambs marked to ewes joined (%) Birth weight of singles (kg) Birth weight of multiples (kg) Growth rate to marking singles (g/h/d) Growth rate to marking multiples (g/h/d)

10 137

65 65.5 65 5.43 4.72 323 278

10 077

62 59.5 39 5.23 4.94 317 225

10 250

60 63.8 125 5.54 4.72 319 266

10 157

52 64.9 33 5.24 5.06 336 274

19 268

38 65.3 132 5.48 4.74 308 248

19 781

34 63.3 18

4.92

281

19 142

34 61.5 144 5.60 4.73 318 256

10 994

33 63.7 45 5.60 4.45 336 286

80 752

28 63.8 136 5.83 4.21 310 251

19 286

24 63.9 158 6.46 4.99 340 270

10 073

23 65.3 143 5.49 5.23 303 250

11 561

23 62.7 70 5.14 4.13 303 232

10 587

19 56.1 111 5.05 3.84 318 224

18 077

19 63.1 111 4.97 4.60 311 246

18 044

19 61.6 89 5.57 4.95 306 255

11 127

18 63.2 144 5.03 4.56 310 247

16 017

18 64.5 117 5.11 4.47 306 264

16 483

18 59.8 100 5.72 4.54 303 234

11 078

18 65.4 106 5.80 4.75 340 238

10 524

18 62.6 89 5.40 3.93 321 216

19 187

16 56.6 119 5.69 4.31 332 225

18 500

16 63.2 125 4.89 4.06 276 228

11 139

15 69.6 173 5.93 4.85 332 245

Table 3 shows the marking rates of lambs born to different sires which varied from 85-100% for singles and from 79-100% for multiples. The high survival of multiple born lambs is likely to be a result of birth weights in the optimum range for maximum survival (four to six kg; Table 3). Birth weight will be determined in part by genetics and in part by nutrition of the ewes and their consequent liveweight and condition scores at joining, mid and late pregnancy.

Table 4 shows the reproductive performance of ewes (daughters) from different sires. Only sires with 15 or more daughters joined are shown. Marking percentage from sire groups ranged from 18-173%, although the latter high marking rate of 173% was from a low number of daughter ewes joined (n=15). Nonetheless, some sire groups with 30-60 daughter ewes were achieving in excess of 125% (Table 4).

The variation in reproductive responses in our sires specifically selected for ‘easy-care’ and carcase traits showed that there is a large variation in the reproductive performance available for selection. Irrespective of whether the enterprise favours wool or meat, reproduction is a key profit driver for both enterprises and should be considered as a primary inclusion to breeding objectives. 

It is prime lamb marking time across the state now. Do your own sums and see where your flock sits. Are you achieving satisfactory reproduction? Will you be joining us at the 100%+ club this year? What would you like to be achieving and how are you going to get there? Consideration of breeding values for direct reproductive traits such as number of lambs weaned (NLW) will assist, as will selecting for indirect traits that are correlated with high reproduction such as weight, muscle and fat. Effective selection and astute management can improve income from meat and wool, and increase disease resistance – all leading to increased profitability.

For more information about the MEF, or if you are interested in benchmarking your own flock performance to marking, contact Beth Paganoni, DAFWA, South Perth, +61 (0)8 9368 3662.

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