Conception rates and serum progesterone concentration in dairy cattle administered gonadotropin releasing hormone 5 days after artificial insemination

Howard, J.M.; Manzo, Richard A.; Dalton, J.C.; Frago, F.; Ahmadzadeh, A.

doi:10.1016/j.anireprosci.2005.10.010

Cited by 39 publications

(38 citation statements)

References 35 publications

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“…In pregnant animals, mean P 4 concentrations were significantly greater in the Ovsynch'Post-AI group compared with the Ovsynch group on day 21 for heifers and day 28 for cows, indicating a response from the result of an accessory CL. Other studies have also observed increases in P 4 from Post-AI treatments of GnRH (Schmitt et al 1996;Willard et al 2003;Howard et al 2006).…”

Section: Discussionmentioning

confidence: 82%

“…One study reported increased PR in dairy cows following GnRH treatment 7 d (Ambrose et al 2000) and 5 d or 11 d after Ovsynch TAI, while in a more recent study no increase in pregnancy was observed (Howard et al 2006). A study that examined treatments of GnRH agonist or hCG given 5 d after AI found 91% of the cows and heifers treated with hCG and 93% of the cows and heifers treated with GnRH agonist formed an accessory CL, after induced estrus (Schmitt et al 1996).…”

Section: Discussionmentioning

confidence: 99%

“…The timing of the GnRH injection is significant, and its effects depend on the follicular status at the time of treatment (Lewis et al 1990). The administration of GnRH on day 5 or 7 has been shown to induce the formation of an additional CL arising from the ovulation of the first-wave dominant follicle present at the time of treatment (Schmitt et al 1996;Howard et al 2006). A recent study by Howard et al (2006) observed increased serum P 4 , but no differences in conception rates when GnRH was administered 5 d after AI.…”

mentioning

confidence: 95%

“…The administration of GnRH on day 5 or 7 has been shown to induce the formation of an additional CL arising from the ovulation of the first-wave dominant follicle present at the time of treatment (Schmitt et al 1996;Howard et al 2006). A recent study by Howard et al (2006) observed increased serum P 4 , but no differences in conception rates when GnRH was administered 5 d after AI. Moreover, practical implementation of hormonal protocols becomes important for farmer compliance, especially on those farms that assign groups of cows to initiate protocols on a weekly basis (Fricke et al 2003).…”

mentioning

confidence: 95%

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Effects of presynchronization and postinsemination treatments on pregnancy rates to a timed breeding Ovsynch protocol in dairy cows and heifers

Gordon¹,

Dinn²,

Rajamahendran³

2010

Can. J. Anim. Sci.

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Gordon, M. B., Dinn, N. and Rajamahendran, R. 2010. Effects of presynchronization and postinsemination treatments on pregnancy rates to a timed breeding Ovsynch protocol in dairy cows and heifers. Can. J. Anim. Sci. 90: 35Á44. This study examined two strategies to improve pregnancy rate (PR) following Ovsynch timed artificial insemination (TAI) for lactating dairy cows (n0225) and nulliparous heifers (n 087). Animals were assigned randomly to receive one of three treatments: Ovsynch protocol (GnRH 7 d before and 48 h after one PGF 2a treatment), Presynch'Ovsynch (two treatments of PGF 2a 14 d apart followed by Ovsynch 14 d later), or Ovsynch'Post-AI GnRH (GnRH 6 d after Ovsynch TAI) for first service breeding. Pregnancy rates among treatments were not different in lactating cows (42.5, 48.0, and 44.9%) or heifers (65.5, 58.6, and 58.6%) for Ovsynch, Presynch'Ovsynch, and Ovsynch'Post-AI, respectively. Cows treated with Ovsynch had lower PR when bred B76 d in milk (DIM) compared with Presynch'Ovsynch or Ovsynch' Post-AI treatments. In addition, cows and heifers that received Post-AI GnRH had greater progesterone (P 4 ) concentrations on day 21 and day 28 post-TAI than the Ovsynch group. Animals with higher P 4 concentrations at initiation of Ovsynch had better PR than those with low P 4 concentrations. Presynch animals had a greater proportion of animals with P 4 values above 1 ng mL(1 at the initiation of Ovsynch than those animals in the Ovsynch group (74.5 vs. 59.4%). Heifers had lower PR if they were B14.6 mo of age (48.9 vs. 75%) or weighed B380 kg (47.4 vs. 70.8%). Although no significance differences in PR were observed between treatments in cows or heifers, DIM in cows and age and weight in heifers affected PR. ; Ovsynch'GnRH post-IA (GnRH 6 jours apre`s IATP par Ovsynch) pour une premie`re saillie. Le taux de conception des vaches en lactation (42,5%, 48,0% et 44,9%) et des ge´nisses (65,5%, 58,6% et 58,6%) ne varie pas avec le traitement (Ovsynch, Presynch'Ovsynch et Ovsynch'post-IA, respectivement). Les vaches recevant le traitement Ovsynch se caracte´risent par un TC plus faible quand on les accouple apre`s moins de 76jours de lactation, comparativement a`celles qui rec¸oivent le traitement Presynch'Ovsynch ou Ovsynch'post-IA. D'autre part, les vaches et les ge´nisses a`qui on administre de la GnRH post-IA pre´sentent une plus forte concentration de progeste´rone (P 4 ) que celles du groupe Ovsynch, le 21 e et le 28 e jour apre`s l'IATP. Les sujets qui pre´sentaient une plus forte concentration de P 4 au de´but du traitement Ovsynch avaient un TC supe´rieur a`ceux pre´sentant une faible concentration de P 4 . Le groupe Presynch comptait un plus grand nombre d'animaux ayant plus de 1 ng de P 4 par mL dans le sang au de´but du traitement Ovsynch que le groupe Ovsynch (74,5% c. 59,4%). Le taux de conception des ge´nisses est plus faible quand elle ont moins de 14,6 mois (48,9% c. 75%) ou pe`sent moins de 380 kg (47,4% c. 70,8%). Bien qu'on n'ait observe´aucun e´cart significatif dans le TC des vaches et ...

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 95%

mentioning

confidence: 95%

See 2 more Smart Citations

Effects of presynchronization and postinsemination treatments on pregnancy rates to a timed breeding Ovsynch protocol in dairy cows and heifers

Gordon¹,

Dinn²,

Rajamahendran³

2010

Can. J. Anim. Sci.

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“…In the present study, administration of GnRH on Day 23 post-AI increased the days to conception and the number of S/C and decreased FSCR in cows treated with M 1 compared to M 2 protocol (Table 1). Several studies have investigated the effect of treatment with GnRH or equine chorionic gonadotropin (eCG) after insemination to improve fertility by inducing ovulation and forming an accessory corpus luteum [13]. Corpus luteum development results in secretion of P4, which influences embryo development, interferon-τ production, and inhibition of the luteolytic cascade.…”

Section: Iiiresults and Discussionmentioning

confidence: 99%

Reproductive parameters in Holstein dairy cows treated with three resynchronization methods

Kor¹

2012

IOSJPBS

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Impact of norgestomet supplementation during early luteal phase on subsequent luteal profiles and conception rate in buffalo: a preliminary study

Pandey

Dhaliwal

Ghuman

et al. 2012

Trop Anim Health Prod

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The current study was aimed to establish the impact of progesterone supplementation (norgestomet progestagen) between days 4 to 10 post-ovulation on subsequent luteal profile and conception rate in buffaloes. The 28 Murrah buffaloes of second to fourth parity, having normal reproductive organs, were estrus synchronized by double PGF(2α) protocol at 11 days apart. The buffaloes were inseminated during mid- to late estrus and thereafter repeated at 24 h interval. The buffaloes were randomly assigned into two groups: (1) control (no treatment, n = 14) and (2) treatment group (CRESTAR ear implant, n = 14). The CRESTAR ear implant (3 mg, norgestomet progestagen) was inserted subcutaneous between days 4 to 10 post-ovulation. The ovaries were scanned at estrus and thereafter on days 4, 10, 16, 21, and 40 post-ovulation to examine the preovulatory follicle (POF) and corpus luteum (CL) diameter. Each ultasonography was followed by blood sample collection for analysis of plasma progesterone concentrations following ovulation. The conception rate was similar (p > 0.05) between treated and control buffaloes. The pregnant buffalo of the control group had larger (p < 0.05) POF diameter than nonpregnant counterparts. The CL diameter was similar (p > 0.05) in both treated and untreated control as well as in their pregnant and nonpregnant buffaloes of the respective groups. The plasma progesterone concentrations were higher (p < 0.05) in the treatment group on the day 10 post-ovulation as compared to the control buffaloes. It is concluded that norgestomet supplementation had no impact on conception rate and CL diameter but enhances the plasma progesterone concentrations following treatment in buffaloes.

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Conception rates and serum progesterone concentration in dairy cattle administered gonadotropin releasing hormone 5 days after artificial insemination

Cited by 39 publications

References 35 publications

Effects of presynchronization and postinsemination treatments on pregnancy rates to a timed breeding Ovsynch protocol in dairy cows and heifers

Effects of presynchronization and postinsemination treatments on pregnancy rates to a timed breeding Ovsynch protocol in dairy cows and heifers

Reproductive parameters in Holstein dairy cows treated with three resynchronization methods

Impact of norgestomet supplementation during early luteal phase on subsequent luteal profiles and conception rate in buffalo: a preliminary study

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