scholarly journals EFFECT OF REPEATED IMPLANTATION WITH ZERANOL FROM BIRTH OR WEANING ON GROWTH AND REPRODUCTION IN BEEF HEIFERS

1987 ◽  
Vol 67 (1) ◽  
pp. 37-42 ◽  
Author(s):  
R. D. H. COHEN ◽  
H. H. NICHOLSON ◽  
E. D. JANZEN
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Skeletal Development ◽  
Carcass Characteristics ◽  
Reproductive Rate ◽  
Beef Heifers ◽  
Pelvic Area ◽  
Group B ◽  
Natural Service ◽  
Growth And Reproduction

Liveweight, pregnancy rate, skeletal development and carcass characteristics were measured on 52 crossbred beef heifers implanted with zeranol at birth then at 110, 204 and 314 d of age (B); at weaning (204 d of age) and at 314 d of age (W); or not implanted (C). At 14 mo of age, the heifers were bred for 6 wk in corrals by natural service. Six weeks later they were slaughtered and their reproductive tracts collected. Height at the withers and pelvic area were measured before slaughter. Mean weaning weights ± SD, corrected to 200 d and for age of dam, were 249 ± 20 kg for group B and 226 ± 22 kg for groups W and C (P < 0.001). At breeding, the heifers weighed 434 ± 24, 416 ± 29 and 392 ± 31 kg for groups B, W and C, respectively (P < 0.001). At slaughter, their liveweights were 531 ± 26, 508 ± 32 and 483 ± 36 kg, respectively (P < 0.001) and carcass weights were 304 ± 17, 286 ± 21 and 270 ± 20 kg, respectively (P < 0.001). Rib eye area was 84.3 ± 8.47, 76.5 ± 8.89 and 72 ± 7.81 cm2, respectively (P < 0.001) but there were no significant differences between groups for cutability (58.2 ± 1.85%), average fat cover (9.4 ± 0.84 mm) or grade (90.3% ± A1/A2 and 9.7% A3/A4). Height at the withers did not differ between groups (46.7 ± 1.61 cm) but zeranol increased pelvic area (186.4 ± 19.54, 178.6 ± 21.84 and 165.3 ± 21.14 cm2 zeranol for groups B, W and C, respectively; (P < 0.05). Pregnancy rate was significantly reduced (P < 0.05) in group B (42.9%) compared with groups W and C (84.2 and 77.8%, respectively). However, examination of the reproductive tracts indicated that only one nonpregnant heifer in each of groups B and C was not cycling and no other abnormalities were found. It was concluded that zeranol will increase live and carcass weights, rib eye area and pelvic area of heifers but that four implants given at birth and at approximately 100-d intervals to 314 d of age will reduce reproductive rate in comparison to heifers implanted twice postweaning or not implanted. Key words: Zeranol, heifer, growth, reproduction, pelvimetry, carcass

The influence of zeranol implantation on growth and reproduction of beef heifers

1991 ◽  
Vol 71 (4) ◽  
pp. 1249-1252 ◽  
Author(s):  
R. N. Kirkwood ◽  
R. D. H. Cohen ◽  
B. D. King ◽  
P. A. Thacker
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Growth Enhancement ◽  
Beef Heifers ◽  
Pelvic Area ◽  
Effect Of Treatment ◽  
Growth And Reproduction

Crossbred beef heifers received a 36-mg implant of zeranol at 60 d of age (R1; n = 35) or at both 60 and 197 d (weaning; R2; n = 32) or received no implants (C; n = 35). R2 heifers were heavier and had greater pelvic areas (P < 0.05 for both) at breeding compared with controls. There was no effect of treatment on the calving rates (78.1 vs. 80.0 vs. 74.3%) or on mean pelvic area at the time of calving (261.1 vs. 260.4 vs. 257.6 cm2) for R2, R1 and C heifers, respectively. We conclude that zeranol can be successfully used for growth enhancement from 60 d of age without detriment to subsequent reproductive performance. Key words: Zeranol, heifers, pregnancy rate, pelvic area

scholarly journals Maternal factors and the prediction of dystocia in beef heifers

1993 ◽  
Vol 73 (2) ◽  
pp. 431-435 ◽  
Author(s):  
B. D. King ◽  
R. D. H. Cohen ◽  
S. McCormac ◽  
C. L. Guenther
Keyword(s):  
Birth Weight ◽  
Discriminant Analysis ◽  
Key Words ◽  
Caesarian Section ◽  
Stepwise Discriminant Analysis ◽  
Gestation Length ◽  
Maternal Factors ◽  
Beef Heifers ◽  
Factors Associated ◽  
Pelvic Area

Stepwise discriminant analysis was used to determine maternal factors associated with dystocia in 564 2-yr-old heifers bred to bulls with below breed average birth weights. Calf birth weight (n = 556) was consistently the most significant (P < 0.001) factor correlated (R2 = 0.31) with dystocia. Other significant (P < 0.001) factors were weight at breeding (n = 376) and calving (n = 559; R2 = 0.11 for both traits). Other factors considered were age at breeding (n = 446), pelvic area at breeding (n = 112) and pregnancy evaluation (n = 297), heifer birth weight (n = 564), gestation length (n = 467) and age at calving (n = 559) but none were significant (P > 0.05). Heifers requiring caesarian section were heaviest (P < 0.05) at breeding and their calves were heaviest (P < 0.05) at birth. Unassisted heifers were heavier at calving (P < 0.05) than assisted heifers. It was concluded that none of the factors examined in this study was a reliable predictor of dystocia in beef heifers but that heifers should be bred at 75–80% of their expected calving weight to reduce the risk of dystocia. Key words: Dystocia, heifer, discriminant analysis

Effects of a growth implant and age of dam on growth and fertility in heifer calves

1994 ◽  
Vol 74 (2) ◽  
pp. 203-208 ◽  
Author(s):  
L. M. Rutter ◽  
P. A. Day
Keyword(s):  
Treatment Group ◽  
Pregnancy Rate ◽  
Field Trial ◽  
Average Daily Gain ◽  
Beef Heifers ◽  
Pelvic Area ◽  
Calving Season ◽  
Growth Implant ◽  
Calving Difficulty ◽  
Daily Gain

A field trial was conducted to determine the effects of a growth implant on growth, pregnancy rate, calving difficulty and calf weaning weight in replacement beef heifers. Heifers were assigned equally to either a control (n = 43; no implant), Ralgro (n = 43) or Synovex-C (n = 42) treatment group based on age of dam and age and weight at the start of the trial (implantation at 45–90 d of age). Neither Ralgro nor Synovex-C enhanced heifer weight or average daily gain (ADG) from the start of the trial to weaning (approximately 7 mo of age), breeding, or pregnancy determination. At breeding, Synovex-C implanted heifers had greater pelvic area than controls while Ralgro implanted heifers were intermediate (control = 149.7, Ralgro = 154.7 and Synovex-C = 157.4 pooled SE of 2.2 cm2; P = 0.05). Pelvic dimensions were similar among treatments at pregnancy determination and there were no treatment effects on calving difficulty. Age of dam affected heifer weight (P = 0.0005) and ADG (P = 0.001) to weaning, with heifers from mature cows weighing more at weaning and having a higher ADG from the start of the study to weaning than heifers from either first- or second-calf cows. Post-weaning performance of heifers from first-calf cows was similar to heifers from mature cows while heifers from second-calf cows were lighter at breeding (P = 0.04) and had a lower ADG from weaning to breeding (P = 0.04). Age of dam did not influence pregnancy rate (P = 0.10), but more heifers from second-calf cows calved late in the calving season (≥ 64 d) compared with heifers from either first-calf or mature cows (P = 0.04). It appears from this field trial that use of a growth implant between 45 and 90 d of age neither enhanced growth nor impaired fertility in beef heifers bred as yearlings. It also appears that second-calf 3-yr-olds may need to be managed separately from the mature cow herd in order to optimize replacement heifer development. Key words: Bovine, replacement heifers, growth implant, age of dam, weight, pregnancy rate

Effect of trenbolene acetate/estradiol implants and estrus suppression on growth performance and carcass characteristics of beef heifers

1997 ◽  
Vol 77 (2) ◽  
pp. 325-328 ◽  
Author(s):  
J. D. Popp ◽  
T. A. McAllister ◽  
W. J. Burgevitz ◽  
R. A. Kemp ◽  
J. P. Kastelic ◽  
...  
Keyword(s):  
Growth Performance ◽  
Key Words ◽  
Feed Efficiency ◽  
Effective Means ◽  
Carcass Traits ◽  
Carcass Characteristics ◽  
Carcass Composition ◽  
Factorial Experiment ◽  
Beef Heifers ◽  
Melengestrol Acetate

The effects of estrus suppression (none, oral melengestrol acetate (0.4 mg d−1) or ovariectomy via Willis spay technique) and an anabolic implant (none or Synovex Plus®) on growth performance and carcass characteristics were determined using 90 beef heifers of composite breeding in a 2 × 3 factorial experiment conducted in the last 50 d before slaughter. Spaying caused no morbidity or mortality and resulted in average daily gains (1.37 kg d−1) comparable to heifers fed melengestrol acetate (1.33 kg d−1). Implanting improved (P < 0.05) feed efficiency and increased (P < 0.05) animal gain, ribeye area, carcass weight and yield and reduced (P < 0.05) intramuscular fat deposition but estrus suppression did not. Method of estrus suppression did not influence (P > 0.05) carcass traits. Spaying and implanting represent an effective means of improving returns from heifers, even late in the finishing period. Key words: Ovariectomy, implants, beef heifers, carcass composition

Repeatability estimates of pelvic diameters measured by Rice pelvimeter in beef heifers

1993 ◽  
Vol 73 (4) ◽  
pp. 977-980
Author(s):  
U. Paputungan ◽  
M. Makarechian ◽  
M. F. Liu
Keyword(s):  
Key Words ◽  
Intraclass Correlation ◽  
Correlation Method ◽  
Reliable Estimate ◽  
Residual Variance ◽  
Beef Heifers ◽  
Single Measurement ◽  
Pelvic Area ◽  
Beef Heifer

Vertical (VP) and horizontal (HP) pelvic diameters were measured with Rice pelvimeter four times in a 3-wk period by the same operator in 143 bred beef heifers (18 ± 0.5 mo old). Pelvic area (PA) was estimated by VP × HP. Pelvic diameters of 30 open beef heifers (19 ± 0.3 mo old) were also measured by two experienced and two inexperienced operators. Repeatability of pelvic measurements was estimated by the intraclass correlation method. The estimates of repeatability of pelvic measurements were relatively moderate (0.53 ± 0.04, 0.46 ± 0.04 and 0.55 ± 0.04 for VP, HP and PA, respectively), indicating that a single measurement may not provide a reliable estimate of pelvic diameter. Between-operator variance was much smaller than the residual variance for each measurement (0.02 vs. 0.39 for VP, 0.06 vs. 0.36 for HP and 38.15 vs. 276.18 for PA). Key words: Beef heifer, pelvic diameters, repeatability

A comparison of two estrus synchronization methods in beef heifers

1998 ◽  
Vol 78 (3) ◽  
pp. 437-439
Author(s):  
L. A. Stephens ◽  
R. Rajamahendran
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Gonadotropin Releasing Hormone ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Releasing Hormone ◽  
Prostaglandin F

This study compared the use of two injections of prostaglandin F2α(PGF2α) given 11 d apart with the use of gonadotropin releasing hormone (GnRH) followed by PGF2α after 7 d for synchronizing estrus in beef heifers. Heifers synchronized with GnRH and PGF2α showed weak signs of estrus and were more difficult to inseminate. There were no significant differences in synchronization rate and pregnancy rate. Key words: Estrus synchronization, beef heifers, gonadotropin releasing hormone, prostaglandin F2α

Efficacy of vaginal spaying and anabolic implants on growth and carcass characteristics in beef heifers.

1990 ◽  
Vol 68 (5) ◽  
pp. 1469 ◽  
Author(s):  
M J Garber ◽  
R A Roeder ◽  
J J Combs ◽  
L Eldridge ◽  
J C Miller ◽  
...  
Keyword(s):  
Carcass Characteristics ◽  
Beef Heifers ◽  
Anabolic Implants

scholarly journals INFLUENCE ON THE OUTCOME OF ART PROGRAMS OF FROZEN-THAWED BLASTOCYSTS EXPANDED ON FIVE OR SIX DAY

2021 ◽  
pp. 68-75
Author(s):  
A.O. Polumiskova ◽  
S.I. Tevkin ◽  
T.M. Jussubaliyeva ◽  
M.S. Shishimorova
Keyword(s):  
Pregnancy Rate ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Clinical Pregnancy ◽  
Clinical Pregnancy Rate ◽  
Miscarriage Rate ◽  
Art Programs ◽  
Group A ◽  
The Difference ◽  
Group B

In order to increase the effectiveness of assisted reproductive technologies (ART) programs, it is essential to improve and develop conditions of embryo culture prior its transfer or cryopreservation of expanded blastocysts on the day 5 or 6. The aim of the study was to assess the effect of human blastocysts’ expansion timing on clinical pregnancy rate (CPR), miscarriage rate (MR) and take-home baby rate (THBR) in frozen-thawed cycles during ART programs. The study involved 2275 frozen embryo transfers (FET) of blastocysts expanded on the day 5 (group A) and 170 FET of blastocysts expanded on the day 6 (group B). The pregnancy rates in both groups were 50.8% and 46.5% respectively. There were no statistically significant differences in clinical pregnancy rate 37.4% and 37.0%, miscarriage rate 26.0% and 21.5% in both groups, respectively. THBR, as the main indicator of efficiency in the programs with transfer of post thawed expanded blastocysts on the day 5 (group A) or 6 (group B) were 36.5% and 35.2%, respectively (the difference is insignificant). In conclusion, in cryoprotocols the day of blastocyst expansion (day 5 or 6 of development) does not statistically affect PR, MR and THBR. In FET programs the quality of blastocyst (excellent and good) should be prioritized regardless of the day of cryopreservation.

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