BAIRNSLEY  HIGHLANDS

ESTIMATING WEIGHT FROM GIRTH

Where smaller numbers of cattle are involved, there are rarely the finances to justify a set of scales to weigh your animals. But having said this, it is important for many breeders to know what animals weigh when it comes to doses of medications (e.g. antibiotics, sedatives) and drenches, but it is also valuable information for those interested in growth rates. Many will use 200-, 400- and 600-day weight to allow comparison of animals from year to year in the same fold, but also between folds. Growth rates are also very important to know that you are finishing your steers  adequately.

Birth weights are best measured on a set of bathroom scales by holding the calf in your arms and deducting your own weight. Thereafter the girth circumference is quite an accurate way of determining an animal's actual weight. With the right amount of pull on the tape you will get easily within 5% of the real weight. Commercially available weight tapes have the weights printed on them and are a convenient way to make these measurements. Eventually, however, the numbers wear off these weight tapes. An alternative is a 3 meter, metal builders tape and converting the measurement in centimetres with the table below.

Where to Measure:

The narrowest part of the chest is the spot, being sure that the animal has its head up. With their head down their chest expands causing an over estimation of their weight. Immediately behind the front legs, over the heart is the spot. Tighten the tape too much (less common mistake) and you under estimate the weight. Pull to lightly (often done) and you over estimate the weight. Practice makes perfect.

 

 

Table of Girth Circumference (cm) to Estimate Weight (kg)

(cm)

(kg)

(cm)

(kg)

(cm)

(kg)

(cm)

(kg)

(cm)

(kg)

68

30

115

136

162

351

209

732

256

1202

69

31

116

140

163

358

210

742

257

1211

70

32

117

143

164

366

211

752

258

1221

71

34

118

147

165

373

212

762

259

1231

72

35

119

150

166

381

213

772

260

1240

73

36

120

153

167

388

214

782

261

1250

74

37

121

157

168

396

215

792

262

1260

75

38

122

161

169

403

216

803

263

1270

76

40

123

164

170

410

217

814

264

1279

77

42

124

168

171

418

218

825

265

1289

78

43

125

172

172

426

219

836

266

1299

79

45

126

176

173

433

220

847

267

1308

80

46

127

180

174

441

221

858

268

1318

81

48

128

184

175

448

222

869

269

1328

82

50

129

188

176

456

223

880

270

1338

83

52

130

192

177

463

224

891

271

1347

84

54

131

196

178

471

225

900

272

1357

85

56

132

201

179

478

226

910

273

1367

86

58

133

205

180

485

227

920

274

1376

87

60

134

210

181

492

228

930

275

1386

88

62

135

214

182

500

229

939

276

1396

89

65

136

219

183

508

230

949

277

1405

90

67

137

223

184

516

231

959

 

 

91

69

138

228

185

524

232

968

 

 

92

72

139

232

186

532

233

978

 

 

93

74

140

236

187

540

234

988

 

 

94

77

141

241

188

548

235

998

 

 

95

79

142

246

189

556

236

1007

 

 

96

82

143

250

190

564

237

1017

 

 

97

84

144

255

191

572

238

1027

 

 

98

87

145

260

192

580

239

1036

 

 

99

90

146

265

193

588

240

1046

 

 

100

93

147

270

194

596

241

1056

 

 

101

96

148

275

195

604

242

1066

 

 

102

98

149

280

196

613

243

1075

 

 

103

101

150

285

197

622

244

1085

 

 

104

103

151

290

198

631

245

1095

 

 

105

106

152

295

199

640

246

1104

 

 

106

109

153

300

200

649

247

1114

 

 

107

112

154

305

201

658

248

1124

 

 

108

115

155

310

202

667

249

1134

 

 

109

118

156

316

203

676

250

1143

 

 

110

121

157

321

204

685

251

1153

 

 

111

124

158

327

205

694

252

1163

 

 

112

127

159

332

206

703

253

1172

 

 

113

130

160

338

207

712

254

1182

 

 

114

133

161

344

208

722

255

1192

 

 

Print this table off & keep it handy.