EFFECTS OF GROUP-FED DIHYDROXYPROGESTERONE ACETOPHENIDE IN COMBINATION WITH AN INJECTION OF ESTRADIOL VALERATE, AND MELENGESTROL ACETATE ON ESTRUS SYNCHRONIZATION AND CONCEPTION IN BEEF HEIFERS

1969 ◽  
Vol 49 (1) ◽  
pp. 113-117 ◽  
Author(s):  
V. N. Tripathi ◽  
W. E. Howell
Keyword(s):  
Oral Administration ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Estradiol Valerate ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Experimental Conditions ◽  
Melengestrol Acetate

Trials were conducted with 208 heifers to study the effect of oral administration of two progestagens on reproductive performance. Under the experimental conditions employed, the levels of dihydroxyprogesterone acetophenide proved inadequate to suppress estrus during treatment. In trials 1 and 2, estrus was synchronized in 71 and 63% of melengestrol acetate (MGA) treated heifers, respectively. For MGA-treated heifers in trial 1, conception rate at the first synchronized estrus was comparable with that in controls, but in trial 2 conception was significantly lower than in controls. Conception rate to first breeding at the estrus subsequent to the MGA-synchronized estrus was comparable with that of controls.

Comparison of Melengestrol Acetate-Prostaglandin F2α to Syncro-Mate B for estrus synchronization in beef heifers

1988 ◽  
Vol 30 (1) ◽  
pp. 1-12 ◽  
Author(s):  
L.N. Brown ◽  
K.G. Odde ◽  
M.E. King ◽  
D.G. LeFever ◽  
C.J. Neubauer
Keyword(s):  
Prostaglandin F2α ◽  
Estrus Synchronization ◽  
Beef Heifers ◽  
Melengestrol Acetate

Melengestrol acetate, estradiol-17β and GnRH for synchronization of estrus and ovulation in beef cows

1999 ◽  
Vol 79 (1) ◽  
pp. 39-43 ◽  
Author(s):  
J. Thundathil ◽  
J. P. Kastelic ◽  
W. O. Olson ◽  
R. B. Cook ◽  
R. J. Mapletoft
Keyword(s):  
Key Words ◽  
Pregnancy Rate ◽  
Beef Cows ◽  
Pregnancy Rates ◽  
Conception Rate ◽  
Estrus Synchronization ◽  
Short Term ◽  
Melengestrol Acetate ◽  
Conception Rates ◽  
Estradiol 17Β

Three experiments were conducted with suckled crossbred beef cows to determine the efficacy of various short-term regimens for synchronizing estrus or ovulation and to determine whether feeding melengestrol acetate (MGA) after timed AI will increase pregnancy rate. In exp. 1, all cows (n = 141) were given 0.5 mg MGA head−1 d−1 for 7 d (days 1 to 7), 1 or 5 mg E17β (and 100 mg progesterone) or 100 µg GnRH on day 1, and 500 µg cloprostenol on day 7. There were no significant differences among groups for estrous or synchronized conception rates (average, 84.4 and 52.1%, respectively). With an identical protocol in exp. 2 (78 cows), by day 11, cows given 5 mg E17β had the highest estrous and synchronized pregnancy rates (65.4 and 42.3%), compared to 1 mg E17β (46.2 and 15.4%) and GnRH (34.6 and 11.5%). Cows not detected in estrus were timed-inseminated and given 100 µg GnRH, 100 h after cloprostenol. There were no significant differences among groups for synchronized conception rate to timed AI (65.0%) or synchronized pregnancy rate to all inseminations (56.4%). Overall, 5 mg E17β gave the most consistent results. In exp. 3, 84 cows were given 100 µg GnRH on days 1 and 9, 500 µg cloprostenol on day 7, and were timed-inseminated on day 10. Half were fed MGA (0.5 mg head−1 d−1) on days 16 to 22, but the pregnancy rate was not different from that in the remaining cows (55.0 versus 47.8%, P > 0.5). Key words: Ovary, follicles, estrus synchronization, beef cows

Reproductive response of yearling beef heifers to a melengestrol acetate-prostaglandin F2± estrus synchronization system1

1992 ◽  
Vol 70 (9) ◽  
pp. 2622-2627 ◽  
Author(s):  
J. R. Jaeger ◽  
J. C. Whittier ◽  
L. R. Corah ◽  
J. C. Meiske ◽  
K. C. Olson ◽  
...  
Keyword(s):  
Estrus Synchronization ◽  
Beef Heifers ◽  
Melengestrol Acetate ◽  
Reproductive Response

497 Effects of post-weaning plane of nutrition and estrus synchronization on reproductive performance of Bos indicus-influenced beef heifers

2017 ◽  
Vol 95 (suppl_4) ◽  
pp. 242-243
Author(s):  
P. Moriel ◽  
M. Piccolo ◽  
P. A. Lancaster ◽  
G. C. Lamb ◽  
J. Vendramini ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Bos Indicus ◽  
Estrus Synchronization ◽  
Beef Heifers

scholarly journals Administration of GnRH on the day of fixed-time artificial insemination (FTAI) and melengestrol acetate (MGA) administration after ftai in non-suckling nelore cattle

2015 ◽  
Vol 36 (5) ◽  
pp. 3149
Author(s):  
Rossane Pereira da Silva ◽  
Karen Martins Leão ◽  
Moraima Castro Rodrigues ◽  
Thaisa Campos Marques ◽  
Natalia Do Carmo Silva ◽  
...  
Keyword(s):  
Oral Administration ◽  
Artificial Insemination ◽  
Fixed Time ◽  
Conception Rate ◽  
Control Group ◽  
Mineral Supplementation ◽  
Melengestrol Acetate ◽  
Buserelin Acetate ◽  
Conception Rates ◽  
Nelore Cattle

<p>The present study evaluated the effect of administering buserelin acetate (GnRH) at the time of fixed-time artificial insemination (FTAI), along with the effect of oral administration of melengestrol acetate (MGA) after FTAI on conception rates in non-suckling Nelore cattle. In Experiment I, the effect of GnRH application at the time of FTAI was evaluated, as was administration of MGA from the 13th through the 18th day following FTAI (D24 to D29 after the initiation of the FTAI protocol). Experiment I was performed in 215 non-suckling cattle of the Nelore breed, divided into four experimental groups: Control group: 56 cows subjected to FTAI without GnRH injection; GnRH group: 51 cows subjected to GnRH at the time of FTAI; MGA Group: 57 cows subjected to FTAI without the application of GnRH with mineral supplementation and the addition of 2.28 g of MGA® Premix per cow per day from D24 to D29 after the initiation of the FTAI protocol; MGA and GnRH group: 51 cows subjected to GnRH injection at the time of FTAI, with mineral supplementation and the addition of 2.28 g of MGA® Premix per cow per day from D24 to D29 after the initiation of the FTAI protocol. In Experiment II, the effect of providing MGA five to ten days after FTAI was evaluated in 196 non-suckling pluriparous Nelore cows, divided into two groups: Control group: 104 cows subjected to FTAI, not supplemented with MGA; treated group: 92 cows supplemented with the addition of 2.28 g of MGA® Premix per cow per day from D15 to D20 after the initiation of the FTAI protocol. Diagnosis of gestation was carried out 45 days after FTAI. Both experiments were conducted using a completely randomised design and analysed via the SAS MIXED procedure. In Experiment I, the control group displayed a lower conception rate (32.1%) compared with the groups administered GnRH, MGA, and both MGA and GnRH, which were respectively provided with MGA after FTAI (45.6%), GnRH at the time of FTAI (50.9%), and the combination of the two treatments (50.9%) (P&lt;0.05). In Experiment II, the control group displayed a higher conception rate (40.38%) compared with the group receiving MGA post-FTAI (18.48%) (P&lt;0.05). It was concluded that the injection of buserelin acetate (GnRH) at the time of FTAI and the oral administration of MGA® Premix from the 13th to the 18th day after FTAI increased the conception rates in non-suckling Nelore cattle. However, when MGA® Premix was administered orally from the fifth to tenth day post-FTAI, conception rates in non-suckling Nelore cattle were reduced.</p>

EFFECT OF GROUP FEEDING OF DIHYDROXYPROGESTERONE ACETOPHENIDE IN COMBINATION WITH AN INJECTION OF ESTRADIOL VALERATE AND MELENGESTROL ACETATE ON OVARIAN ACTIVITY IN BEEF HEIFERS

1968 ◽  
Vol 48 (3) ◽  
pp. 449-453
Author(s):  
V. N. Tripathi ◽  
W. E. Howell
Keyword(s):  
Ovarian Follicles ◽  
Average Level ◽  
Estradiol Valerate ◽  
Ovarian Activity ◽  
Corpora Lutea ◽  
Beef Heifers ◽  
First Feeding ◽  
Melengestrol Acetate ◽  
Group Feeding

An experiment was conducted with 36 yearling beef heifers to determine the effect of orally administered progestagens on the incidence and size of detectable ovarian follicles and corpora lutea. Dihydroxyprogesterone acetophenide (DHPA) was fed at an average level of 75 mg/head/day for 9 days, each heifer being injected intramuscularly with 5 mg estradiol valerate (EV) 24 hours after the first feeding. To a second group, melengestrol acetate (MGA) was fed at an average level of 0.45 mg/head/day for 18 days. While there was a decrease in the incidence of detectable follicles during DHPA + EV treatment, there was no significant reduction in the incidence of detectable corpora lutea. During MGA treatment, the incidence of detectable follicles increased, while the incidence of detectable corpora lutea decreased. Five of 12 heifers ovulated during DHPA + EV treatment, whereas ovulation was completely suppressed during MGA administration.

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.

Estrus synchronization in beef heifers with progestin-based protocols

2004 ◽  
Vol 62 (8) ◽  
pp. 1518-1528 ◽  
Author(s):  
S.L. Wood-Follis ◽  
F.N. Kojima ◽  
M.C. Lucy ◽  
M.F. Smith ◽  
D.J. Patterson
Keyword(s):  
Estrus Synchronization ◽  
Beef 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.

THE ACCUMULATIVE EFFECT OF FINNSHEEP BREEDING IN CROSSBREEDING SCHEMES: REPRODUCTIVE PERFORMANCE

1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR
Keyword(s):  
Body Weight ◽  
Mortality Rate ◽  
Key Words ◽  
Litter Size ◽  
Reproductive Performance ◽  
Conception Rate ◽  
Ovulation Rate ◽  
Genetic Groups ◽  
Linear Regressions ◽  
Size At Birth

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities

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