Increase in the reproductive efficiency of primiparous and multiparous Nellore cows following moxidectin treatment at the onset of a fixed-time artificial insemination protocol

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.

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Cooled semen for fixed-time artificial insemination in beef cattle

Reproduction Fertility and Development ◽

10.1071/rd14185 ◽

2016 ◽

Vol 28 (7) ◽

pp. 1004 ◽

Cited By ~ 9

Author(s):

Juliana C. Borges-Silva ◽

Márcio R. Silva ◽

Daniel B. Marinho ◽

Eriklis Nogueira ◽

Deiler C. Sampaio ◽

...

Keyword(s):

Beef Cattle ◽

Sperm Motility ◽

Artificial Insemination ◽

Egg Yolk ◽

Fixed Time ◽

Pregnancy Rates ◽

Reproductive Efficiency ◽

Sperm Abnormalities ◽

Hypoosmotic Swelling Test ◽

Interesting Approach

This study evaluated the use of cooled semen in a fixed-time artificial insemination (FTAI) program compared with frozen–thawed semen to improve pregnancy rates in beef cattle. Ejaculates of three bulls were collected and divided into two treatments: (1) frozen–thawed semen and (2) cooled semen. Egg-yolk extender without glycerol was used for the cooled semen treatment. Straws (25 × 106 spermatozoa) were submitted to cooling for preservation at 5°C for 24 h, after which FTAI was performed. Nelore cows (n = 838) submitted to FTAI were randomly inseminated using frozen–thawed semen or cooled semen. There was a 20% increase in the pregnancy per AI (P AI–1) using cooled semen compared with frozen–thawed semen (59.9 ± 4.7 vs 49.4 ± 5.0%; P < 0.005). There was no difference in P AI–1 among the bulls (P = 0.40). The frozen–thawed semen had fewer functional spermatozoa than did the cooled semen when evaluated by sperm motility (61.7 vs 81.0%), slow thermoresistance test (41.7 vs 66.7%) and hypoosmotic swelling test (38.3 vs 53.7%; P < 0.05). The percentage of sperm abnormalities did not differ between the freeze–thawing and cooling processes (18.6 vs 22.1%; P > 0.05). Because there was less damage to spermatozoa and improvement in P AI–1, the use of cooled semen instead of frozen–thawed semen is an interesting approach to increase reproductive efficiency in cattle submitted to a FTAI protocol.

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Use of cooled buffalo semen as a strategy to increase conception rates in fixed-time artificial insemination programs during unfavorable reproductive periods

Arquivo Brasileiro de Medicina Veterinária e Zootecnia ◽

10.1590/1678-4162-12142 ◽

2021 ◽

Vol 73 (3) ◽

pp. 560-570

Author(s):

J. Almeida ◽

M.F. Brito ◽

B.P. Neves ◽

V.A.B. Becerra ◽

P.A. Auler ◽

...

Keyword(s):

Artificial Insemination ◽

Fixed Time ◽

Reproductive Season ◽

The Other ◽

Reproductive Efficiency ◽

Frozen Semen ◽

Significant Difference ◽

Buffalo Semen ◽

Four Blocks ◽

Artificial Vagina

ABSTRACT The objective of this study was to compare the reproductive efficiency of dairy buffaloes undergoing fixed-time artificial insemination (FTAI) protocols based on progesterone/estrogen (P4/E2) and eCG during unfavorable breeding season using cooled (CS) and frozen semen (FS). A total of 446 buffaloes (> 40 days postpartum) were randomly distributed into four blocks (years): B1-2014 (n = 143), B2-2015 (n = 34), B3-2016 (n = 90), and B4-2017 (n = 179). Each block was subdivided into two (AI with CS and FS using the same ejaculate of each bull). Thus, the block subdivision was as follows: B1 (CS = 71 and FS = 72); B2 (CS = 18 and FS = 16); B3 (CS = 47 and FS = 43); and B4 (CS = 90 and FS = 89). The ejaculates of eight Murrah bulls collected using an artificial vagina were divided into two aliquots: one aliquot was diluted in Botu-Bov® commercial extender and cooled (BB-CS), and the other was diluted in the same extender and frozen (BB-FS). BB-CS aliquots were cooled at 5 °C/24 h using a refrigerator. BB-FS group aliquots were also cooled, and after equilibrating at 5 °C for 4 h, were placed in a 21-L Styrofoam box, 5 cm above the surface of liquid nitrogen. In the afternoon (A) on D0 (2:00 p.m.) the animals received EB 2.0 mg IM (Estrogin®) and an ear implant (CRESTAR® 3.0 mg P4). At D9 (A), the implant was removed, and the animals received eCG 400 IU IM (Folligon® 5000) + Cloprostenol PGF2α 0.530 mg IM (Sincrocio®). At D10 (A), the animals received EB 1.0 mg IM (Estrogin®), and at D12 (8:00 a.m.), AI was performed. At D42, pregnancy was diagnosed via ultrasonography. Total CRs were 48.2% CS and 34.6% FS for years 2014 to 2017, with a significant difference of 13.7% (P<0.05). In conclusion, cooled semen resulted in higher CR than frozen semen in dairy buffaloes under the P4/E2 and eCG FTAI during the unfavorable reproductive season.

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Reproductive efficiency Nellore and crossbred cows submitted to administration of melengestrol acetate (MGA) after FTAI protocols

Research Society and Development ◽

10.33448/rsd-v9i10.8897 ◽

2020 ◽

Vol 9 (10) ◽

pp. e5679108897

Author(s):

Alan Gabriel Valero ◽

Carlos Renato de Freitas Guaitolini ◽

Andre Maciel Crespilho ◽

Gabriela Passamani da Cruz ◽

Marcio Luiz Denck Tramontin ◽

...

Keyword(s):

Statistical Analysis ◽

Breeding Season ◽

Medroxyprogesterone Acetate ◽

Artificial Insemination ◽

Fixed Time ◽

Pregnancy Rates ◽

Conception Rate ◽

Reproductive Efficiency ◽

Crossbred Cows ◽

Melengestrol Acetate

This study aimed to evaluate the influence of medroxyprogesterone acetate (MGA) supplementation between the 13th and 20th day after Fixed-Time-Artificial Insemination (FTAI), on the conception and gestation rates of Nellore and crossbred cows (Nellore x Angus), pluriparous and lactating. For the study, 349 Nellore cows and 270 crossbred cows were selected, distributed into 1) group G1 (n=176): Nellore cows submitted to the FTAI protocol, without MGA supplementation; 2) group G2 (n=173): Nellore cows submitted to the FTAI protocol, with supplementation for 7 days of MGA® (0.28g/AU/day) from the 13th post-FTAI; 3) group G3 (n=119): crossbred cows: FTAI protocol, without MGA supplementation; 4) group G4 (n=151): crossbred cows: FTAI protocol followed by MGA supplementation for 7 days (0.28g/AU/day), from the 13th to the 20th day after FTAI. For statistical analysis, the procedures MIXED and GLIMMIX from SAS were used. G3 had higher rates of conception (CR=85.7%) and pregnancy (PR=95.8%) at the end of the breeding season (P<0.05), without the interference of supplementation with MGA (P>0.05). G1 females had a lower conception rate (TC=76.7%) (P<0.05), with the use of MGA® (CR-MGA=59.5%), but similar rates of pregnancy (PR=90.3%; PR-MGA=92.5%) to the G2, at the end of the breeding season (P>0.05). When G2 and G4 were compared, we found that crossbred females supplemented had higher rates of conception and pregnancy. In conclusion, crossbred animals have higher conception and pregnancy rates at the end of the breeding season. Besides, we found that Nellore females had a lower conception rate, with the use of MGA® Premix.

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The use of fixed time artificial insemination programmes for the use of sexed semen in block calving dairy heifers

Livestock ◽

10.12968/live.2021.26.3.124 ◽

2021 ◽

Vol 26 (3) ◽

pp. 124-130

Author(s):

Mike Kerby ◽

Tom Clarke ◽

Tom Angel ◽

Kythé Mackenzie

Keyword(s):

Artificial Insemination ◽

Prostaglandin F2α ◽

Cost Benefit ◽

Fixed Time ◽

Reproductive Efficiency ◽

Costs And Benefits ◽

Dairy Heifers ◽

Conception Rates ◽

Sexed Semen

In seasonal block calving herds reproductive efficiency can have a significant impact on productivity and profitability. Within this it is key that the nulliparous heifers calve down promptly in the block, and if these heifers can have heifer calves it will expediate genetic gain. There is extensive research into the conception rates of differing protocols and the literature is reviewed to support the choice of protocol used in the subsequent case study. The case study uses a 6-day progesterone protocol with two injections of prostaglandin F2α and sexed semen; it demonstrated acceptable conception rates as well as the variability that can occur between different bulls' semen straws. Finally, the case study assesses the costs and benefits of the synchronisation programme and concludes a cost benefit of £88.55 per heifer.

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Effect of recombinant bovine somatotropin on pregnancy rates of Nellore cows resynchronized with the use of new DIB and third use, and inseminated at fixed-time

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v4i1.4304 ◽

2015 ◽

Vol 4 (1) ◽

pp. 356-362

Author(s):

Josemara Silva Santos ◽

Tania Cavalcante ◽

Francisca Elda Ferreira Dias ◽

Domenica Palomaris Mariano de Souza ◽

Alencariano J.S. Falcão ◽

...

Keyword(s):

Artificial Insemination ◽

Linear Models ◽

Plasma Concentrations ◽

Fixed Time ◽

Estradiol Benzoate ◽

Pregnancy Rates ◽

Recombinant Bovine Somatotropin ◽

Equine Chorionic Gonadotropin ◽

Rectal Palpation ◽

Intravaginal Device

The objective of the experiment was to evaluate the effects of recombinant bovine somatropin (rbST), and the reuse of the progesterone (P4) releasing devices in resynchronization, on the pregnancy rates of Nellore cows submitted to fixed-time artificial insemination. A group of 123 multiparae Nellore cows, was submitted to a resynchronization protocol: on day 0 a Bovine Intravaginal Device (DIB® ) with 1,0g of P4 was implanted, associated with intramuscular administration of 2,0mg of estradiol benzoate (IM); on day 8 DIB was removed; and 1,0mg of estradiol cypionate, 0,15mg of prostaglandin F2? and 300 UI of equine chorionic gonadotropin were administered; on day 10, fixed-time artificial insemination was conducted (FTAI). The cows were randomized into G1 (n=12) – without rbST / with used Bovine Intravaginal Device, G2 (n=50) – without rbST / with new DIB, G3 (n=11) - with rbST / with used DIB and G4 (n=50) – with rbST/ with new DIB. rbST was introduced on the eighth day of the protocol. Sixty days after TAI, pregnancy diagnoses were conducted, via rectal palpation. Blood samples were taken on day 0, 8 and 10 of the protocol, in order to assess P4 plasma concentrations. Pregnancy rates were statistically evaluated through Generalized Linear Models Theory and their significance was tested with Analysis of Deviance. Pregnancy rates were 58%, 40%, 81% and 48% for G1, G2, G3 and G4, respectively, with significant statistical difference for G3. Plasma concentrations of P4 were not statistically different among groups, or collections. In view of the results obtained, we concluded that the administration of rbST in association with P4 DIB, used for the third time, improves pregnancy rates. Estrus resynchronization and re-insemination positively impacted pregnancy rates.

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Parenteral Copper Administration at the Beginning of a Fixed-Time Artificial Insemination Protocol in Beef Cattle: Effect on Ovarian Function and Pregnancy Rates

Biological Trace Element Research ◽

10.1007/s12011-021-02795-y ◽

2021 ◽

Author(s):

Juan Patricio Anchordoquy ◽

Santiago Nicolás Lorenti ◽

Gustavo Sebastián Polero ◽

Nicolás Agustín Farnetano ◽

Diana Esther Rosa ◽

...

Keyword(s):

Beef Cattle ◽

Artificial Insemination ◽

Ovarian Function ◽

Fixed Time ◽

Pregnancy Rates

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Luteogenesis and Embryo Implantation Are Enhanced by Exogenous hCG in Goats Subjected to an Out-of-Season Fixed-Time Artificial Insemination Protocol

Biology ◽

10.3390/biology10050429 ◽

2021 ◽

Vol 10 (5) ◽

pp. 429

Author(s):

Jorge A. Bustamante-Andrade ◽

César A. Meza-Herrera ◽

Rafael Rodríguez-Martínez ◽

Zurisaday Santos-Jimenez ◽

Oscar Ángel-García ◽

...

Keyword(s):

Corpus Luteum ◽

Artificial Insemination ◽

Body Condition Score ◽

Embryo Implantation ◽

Implantation Rate ◽

Fixed Time ◽

Efficiency Index ◽

Control Group ◽

Condition Score ◽

Interesting Approach

The aim of this study was to evaluate the possible effect of two doses of hCG (100 and 300 IU) applied at two different times (7 and 14 d) after a fixed-time artificial insemination protocol (FTAI) upon some variables involved in the embryonic implantation rate in goats during the natural deep anestrous season (April, 25° north). The experimental units considered crossbred, multiparous, anovulatory goats (n = 69, Alpine, Saanen, Nubian x Criollo), with average body weight (43.6 ± 5.7 kg) and body condition score (1.86 ± 0.28 units) located in northern–semiarid Mexico (25° N, 103° W). Once the goat’s anestrus status was confirmed, goats were subjected to an estrus induction protocol. Upon estrus induction confirmation, goats (n = 61) were subjected to a FTAI procedure. Immediately after the FTAI, the goats were randomly distributed to five experimental groups: (1). G100-7 (n = 13) 100 IU, hCG 7 d post-FTAI, (2). G100-14 (n = 12) 100 IU hCG, 14 d post-FTAI, (3). G300-7 (n = 12) 300 IU, hCG, 7 d post-FTAI, (4). G300-14 (n = 12) 300 IU hCG 14 d post-FTAI, and (5). Control group, CONT (n = 12) 0.5 mL saline, 7 and 14 d post-FTAI. The response variables conception rate (39.36 ± 0.23), fertility rate (27.96%), prolificacy rate (1.1 ± 0.29 kids), ovulation rate (0.74 ± 0.20 corpus luteum) corpus luteum diameter (10.15 ± 0.59 mm), embryo number (1.58 ± 0.20), and embryo implantation rate (48.96%), did not differ between treatments. However, while the variables fecundity rate (67%), embryo efficiency index-1 (33.99 ± 0.20%), and embryo efficiency index-2 (27.94 ± 0.30%) were favored by the G300-14 treatment, the corpus luteum area was favored (p < 0.05) by both G300-7 (113.30 ± 0.19 mm2) and G300-14 (103.04 ± 0.17 mm2). Such reproductive strategy emerges as an interesting approach, not only to enhance the out-of-season reproductive outcomes, but also to boost one of the main rulers defining the global reproductive efficiency of a heard, namely, the embryo implantation efficiency.

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