Effect of treatment with ivermectin on reproductive performance of yearling beef heifers

1995 ◽  
Vol 44 (2) ◽  
pp. 189-197 ◽  
Author(s):  
R.L. Larson ◽  
L.R. Corah ◽  
M.F. Spire ◽  
R.C. Cochran
Keyword(s):  
Reproductive Performance ◽  
Beef Heifers ◽  
Effect Of Treatment

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 Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-synch Protocol in Heifers

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 849
Author(s):  
Aitor Fernandez-Novo ◽  
Sergio Santos-Lopez ◽  
Jose Luis Pesantez-Pacheco ◽  
Natividad Pérez-Villalobos ◽  
Ana Heras-Molina ◽  
...  
Keyword(s):  
Animal Welfare ◽  
Reproductive Performance ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Reproductive Efficiency ◽  
Beef Heifers ◽  
Animal Management ◽  
Commercial Farms ◽  
Beef Herds ◽  
Farm Economics

In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56-h protocol (5dCo56; n = 10), 5d Co-synch 72-h (5dCo72; n = 17), or the modified 5d Co-synch 72-h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). In experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72-h or 6-d Co-synch 48-h protocol and conception rate (CR) studied. In experiment 1, the three protocols led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72), and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (p = 0.907). Therefore, delaying removal by 24 h provides satisfactory results without reducing reproductive efficiency of heifers.

scholarly journals Effect of Diet on Replacement Beef Heifer Growth and Reproductive Performance

2017 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Janice G. P. Bowman ◽  
Bok F. Sowell
Keyword(s):  
Reproductive Performance ◽  
Average Daily Gain ◽  
Average Weight ◽  
Beef Heifers ◽  
Roller Mill ◽  
Feed Cost ◽  
Alfalfa Hay ◽  
Grass Hay ◽  
Beef Heifer ◽  
Daily Gain

One hundred-one crossbred beef heifers (average weight 256.1 kg) were used to evaluate the effects of diet during an 84-day period, on growth and reproductive performance. The four treatments were: 1) grass hay; 2) grass hay + 0.9 kg/day barley; 3) grass hay + 1.8 kg/day barley; and 4) alfalfa hay. Heifers were assigned randomly to 12 pens by weight (three pens/treatment). Prior to feeding, barley was cracked through a roller-mill. Heifers consuming alfalfa hay or grass hay + 1.8 kg barley gained 39% faster (0.68 and 0.74 kg/day, respectively; P = 0.01) than heifers consuming grass hay alone (0.51 kg/day). Heifers consuming grass hay + 0.9 kg barley were intermediate in average daily gain (ADG; 0.63 kg/day). Hay intake was 16% greater (P < 0.10) by heifers consuming alfalfa hay, grass hay, and grass hay + 0.9 kg barley compared with those consuming grass hay + 1.8 kg barley (average 8.1 vs 7.0 kg/day). Using costs (USD) of $0.066/kg, $0.099/kg, and $0.0935/kg for grass hay, alfalfa hay, and barley, respectively, feed cost/day was greatest (P < 0.01) for alfalfa hay ($0.81/day), intermediate for the grass hay + barley diets (average $0.63/day), and lowest for grass hay ($0.53/day). Cost/kg gain was less (P < 0.10) for grass hay + 1.8 kg barley compared with alfalfa hay. No diet differences (P > 0.70) were found in reproductive performance of the heifers. Feeding replacement heifers alfalfa hay resulted in performance equivalent to feeding grass hay + 1.8 kg barley, but the alfalfa hay diet had a higher cost.

scholarly journals 216 Effects of low doses of GnRH at CIDR removal on estrus expression and conception rates in beef heifers

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 124-124
Author(s):  
Jerica J J Rich ◽  
Emmalee J Northrop ◽  
Kaitlin M Epperson ◽  
Saulo Menegatti Zoca ◽  
Stephanie D Perkins ◽  
...  
Keyword(s):  
Random Effect ◽  
Fixed Time ◽  
Low Doses ◽  
Beef Heifers ◽  
Conception Rates ◽  
Effect Of Treatment ◽  
Independent Variable ◽  
Estrus Response ◽  
To Receive

Abstract Previous studies evaluating single and multiple GnRH injections at time of CIDR removal have reported decreased interval to estrus and increased expression of estrus, and increased conception rates, respectively. Thus, the objective of this study was to compare the effects of supplementing GnRH at CIDR removal on expression of estrus and conception rates in beef heifers following the 7-d CO-Synch + CIDR protocol. Heifers (n = 1,482) from 11 herds over two years were synchronized using the 7-d CO-Synch + CIDR fixed time AI (FTAI) protocol and were randomly assigned to receive one of three treatments at CIDR removal [0 µg GnRH (0); 5 µg GnRH (5); or 5 µg at CIDR removal and 5 µg 12 h later (5 + 5)]. Expression of estrus and conception rates were analyzed using the GLIMMIX procedure of SAS with treatment as an independent variable and herd as a random effect. There was no effect of treatment on expression of estrus (P = 0.38), or AI conception rates (P = 0.85). There was an effect of estrus (P < 0.01) and a treatment × estrus interaction (P = 0.02). Animals that exhibited estrus prior to FTAI had increased (P < 0.01) conception rates compared with those that did not. Animals that exhibited estrus had increased (P < 0.01) conception rates compared with non-estrus animals in the 0 and 5 + 5 µg groups (54 ± 3% vs 34 ± 3%, and 52 ± 3% vs 36 ± 3%, respectively), but in the 5 µg group, there was no difference (P = 0.53) in conception rates between estrus and non-estrus animals (44 ± 3% vs 41 ± 3%, respectively). In conclusion, estrus expression increased pregnancy success, but supplementation with 5 or 5 + 5 µg of GnRH at CIDR removal did not improve estrus response or conception rates in beef heifers.

scholarly journals Impact of slick hair trait on physiological and reproductive performance in beef heifers consuming ergot alkaloids from endophyte-infected tall fescue1

2019 ◽  
Vol 97 (4) ◽  
pp. 1456-1467 ◽  
Author(s):  
Rebecca K Poole ◽  
Thomas L Devine ◽  
Kyle J Mayberry ◽  
Joan H Eisemann ◽  
Matt H Poore ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Ergot Alkaloids ◽  
Beef Heifers ◽  
Slick Hair

374 Effects of Hydroxy Trace Mineral Supplementation on Gain and Reproductive Performance in Beef Heifers.

2018 ◽  
Vol 96 (suppl_2) ◽  
pp. 201-201
Author(s):  
S A Springman ◽  
T L Meyer ◽  
M E Drewnoski ◽  
R N Funston
Keyword(s):  
Reproductive Performance ◽  
Beef Heifers ◽  
Trace Mineral ◽  
Mineral Supplementation

The effect of zeranol implants on growth and pregnancy loss in beef heifers

1994 ◽  
Vol 74 (1) ◽  
pp. 73-76 ◽  
Author(s):  
B. D. King ◽  
R. N. Kirkwood ◽  
C. L. Guenther ◽  
R. D. H. Cohen ◽  
G. A. Bo ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Reproductive Performance ◽  
Pregnancy Loss ◽  
Average Daily Gain ◽  
Fetal Loss ◽  
Live Weight ◽  
Fetal Mortality ◽  
Beef Heifers ◽  
Calf Survival ◽  
Daily Gain

Live weight, average daily gain (ADG) and reproductive performance were compared between heifers implanted with zeranol at birth, 100 and 200 d of age (n = 54) and those not implanted (n = 50). Zeranol implantation resulted in increased (P < 0.05) ADG from birth to weaning, weaning weight, ADG from weaning to breeding, breeding weight and calving weight but did not affect (P > 0.05) calf birth weights, incidence of dystocia, calf survival or gestation lengths. Zeranol implants did not affect (P > 0.05) the incidence or magnitude of the pre-ovulatory LH surge or the number of heifers that ovulated between 48 and 168 h after cloprostenol injection. Pregnancy rate 42 d after bull entry did not differ between the two groups (P > 0.10), tended toward a difference at 72 d (P < 0.10), and was different at 133 d (P < 0.05), with implanted heifers having a lower pregnancy rate than non-implanted heifers. Between day 72 and day 133 after bull entry there was a 10% embryonic or fetal mortality rate in zeranol-implanted heifers, which differed from the 0% loss in non-implanted heifers (P < 0.05). We conclude that serial implants of zeranol from birth reduced the pregnancy rate in heifers and that this effect was due to early fetal loss. Key words: Zeranol, embryonic/fetal mortality, bovine, pregnancy rate, ultrasonography

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