Evaluation of F₁ cows sired by Brahman, Boran and Tuli for reproductive and maternal performance /
Birth (BW) (n=846) and weaning weight (WW) (n=792), pregnancy rate (PR) (n=977), calving rate (CR) (n=966), weaning rate (WR) (n=960), calf survival (CS) (n=848) and cow's weight at palpation (PW) (n=1,124) were evaluated from 1994 to 2001 in 143 F₁ cows sired by Brahman (B), Boran (Bo) and Tul...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2002.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726460241&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Birth (BW) (n=846) and weaning weight (WW) (n=792), pregnancy rate (PR) (n=977), calving rate (CR) (n=966), weaning rate (WR) (n=960), calf survival (CS) (n=848) and cow's weight at palpation (PW) (n=1,124) were evaluated from 1994 to 2001 in 143 F₁ cows sired by Brahman (B), Boran (Bo) and Tuli (T) bulls and born to Hereford and Angus cows. PR, CR, WR, CS and PW were evaluated using as model components: sire breed of dam, dam breed of dam and calf's birth year/age of dam as fixed effects, dam's sire within sire breed, dam within dam's sire within sire breed as random effects. BW and WW were evaluated using the same model and adding the calf's gender. All two-way interactions were tested for significance. Calf's birth year/age of dam was significant for all variables (P<0.05) but CS. BW adjusted means for calves out of cows by B, Bo and T sires were 35.53± 0.31, 34.78±0.48 and 35.49±0.41 kg respectively, and were not different (P>0.05). Significant differences (P<0.05) were found among the WW adjusted means of calves out of B, Bo and Tuli cows, with values of 229.6±2.3, 214.6 and 200.4 kg respectively. For both variables, male calves had higher values (P<0.05) than females. PR adjusted means for B, Bo and T sire breeds were 0.890±0.014, 0.946±0.019 and 0.919±0.016, and were not different (P>0.05). CR adjusted means for B, Bo and T sire breeds were 0.863±0.016, 0.927±0.020 and 0.890±0.017 respectively, with Bo higher (P < 0.05) than B. CS adjusted means for B, Bo and T breeds were 0.932±0.014, 0.952±0.017 and 0.939±0.014 showing the same trend as CR, but no differences (P > 0.05) among them. WR showed the same trend as CR and CS, with adjusted means of 0.808±0.019, 0.874±0.024 and 0.837±0.020 for B, Bo and T breeds, and not being different (P > 0.05). PW adjusted means in mature cows evaluated were 600.7±7.4, 513.7±9.7 and 512.9±8.2 kg, with those sired by B being heavier (P<0.05) than those sired by the other breeds. Boran-sired cows showed higher reproduction rates and Brahman-sired females weaned heavier calves. |
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| Item Description: | Vita. "Major Subject: Animal Science". In title numerals are used in subscript. |
| Physical Description: | xv, 159 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 135-144). |