Revisión de los programas de sincronización ovárica basados en el uso de hormona liberadora de gonadotropinas y prostaglandina F2α para novillas de leche y de carne

Sanz, A.; Macmillan, K.; Colazo, M.G.

doi:10.12706/itea.2019.002

Cited by 3 publications

(5 citation statements)

References 28 publications

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“…In the current study, 80% of heifers were pregnant with a single AI, which is a higher pregnancy rate than reported other studies using a similar synchronization protocol [30] or cosynch protocols [42]. This high pregnancy rate could be associated with the optimal body development of heifers at AI (approximately 70% of the mature LW).…”

Section: Heifer Reproductive Performancecontrasting

confidence: 55%

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves

Noya

Casasús

Ferrer

et al. 2019

Animals

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In this study, we evaluated the effects of maternal subnutrition in early pregnancy on the growth and reproductive performance of female offspring during their rearing, first gestation, and lactation. We inseminated 21 Parda and 15 Pirenaica multiparous cows and assigned them to a CONTROL (100% of nutrition requirements) or SUBNUT (65%) diet until day 82 of gestation. Cows were fed 100% requirements afterward. During the rearing of female offspring, growth, physiological profiles and ovarian follicular dynamic were studied. At 16 months old, heifers were inseminated. After first calving, dam–calf weights were recorded during lactation. Heifers born from CONTROL cows were heavier at weaning (four months old) than heifers born from SUBNUT cows, but this difference disappeared at the end of rearing and during the first gestation and lactation periods. All heifers reached puberty at a similar age and live weight. During rearing, SUBNUT heifers had higher concentrations of non-esterified fatty acids, urea, and cholesterol and a lower antral follicle count than CONTROL, but no difference was found in their fertility rate. After heifer first calving, dam–calf weights were similar among groups. In conclusion, maternal undernutrition reduced offspring postnatal gains at weaning, compromising metabolic status and follicle population during rearing but did not impair performance in the first gestation and lactation periods of beef heifers.

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Section: Heifer Reproductive Performancecontrasting

confidence: 55%

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves

Noya

Casasús

Ferrer

et al. 2019

Animals

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“…A total synchronization rate of 80-90% was observed in the current work with the three hormonal protocols tested in dairy heifers, similarly to previous studies [16,17]. Likewise, a conception rate around 60% was obtained in beef heifers, comparable to that achieved in other studies with the protocol Cosynch 72 and 56 h [9,10,[13][14][15][30][31][32][33][34][35][36].…”

Section: Discussionsupporting

confidence: 90%

“…The rst protocol to synchronize ovulation for xed-time arti cial insemination (FTAI) based on gonadotropin-releasing hormone (GnRH) was reported in 1995 [1]. Since then, several modi cations have been developed, including such protocols as G6G [2], double-ovsynch [3], presynch-ovsynch [4], 5 day ovsynch [5,6], 7 day Co-synch [7], 5 day Co-synch [8] and others [9,10]. Research on xed-time arti cial insemination has traditionally focused on dairy cattle, but some protocols and data are available for beef cattle [10].…”

Section: Introductionmentioning

confidence: 99%

Effects of delaying the removal of the intravaginal progesterone device by 24 h in the 5d Co-synch protocol in heifers

Fernández-Novo¹,

Santos-Lopez

Pesantez-Pacheco

et al. 2021

Preprint

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Background In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. This study 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 whether such a modified protocol would provide an acceptable, 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), the standard 5d Co-synch 72 h protocol (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). Heifers were considered synchronized (TSR) if serum progesterone value > 1.0 ng/mL and the corpus luteus (CL) was detectable by ultrasonography on Day 5, if progesterone < 1.0 ng/mL and at least one follicle had a diameter > 8 mm on Day 7.5, and if progesterone > 1.0 ng/mL and CL was detectable on Day 15. In Experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72 h or 6d Co-synch 48 h protocol and conception rate (CR) studied. Results In experiment 1, the three protocols in dairy heifers 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). Heifer age, body condition score or stress score did not significantly affect conception rate. Conclusions These results suggest that delaying removal of the intravaginal progesterone device by 24 h during the standard 5d Co-synch 72 h protocol provides satisfactory results without reducing reproductive efficiency of heifers.

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“…Moreover, dairy heifers show a comparable ovarian physiology to beef heifers [ 20 , 21 ]. Likewise, a conception rate around 60% was obtained in beef heifers, comparable to that achieved in other studies with the protocol Co-synch 72 and 56 h [ 9 , 10 , 13 , 14 , 16 , 18 , 24 , 27 , 28 , 29 , 30 , 31 ].…”

Section: Discussionsupporting

confidence: 85%

“…The first protocol to synchronize ovulation for fixed-time artificial insemination (FTAI) based on gonadotropin-releasing hormone (GnRH) was reported in 1995 [ 1 ]. Since then, several modifications have been developed, including such protocols as G6G [ 2 ], double-ovsynch [ 3 ], presynch-ovsynch [ 4 ], five-day ovsynch [ 5 , 6 ], seven-day Co-synch [ 7 ], five-day Co-synch [ 8 ], and others [ 9 , 10 ]. Research on fixed-time artificial insemination has traditionally focused on dairy cattle, but some protocols and data are available for beef cattle [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

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

Fernández-Novo

Santos-Lopez

Pesantez-Pacheco

et al. 2021

Animals

View full text Add to dashboard Cite

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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Revisión de los programas de sincronización ovárica basados en el uso de hormona liberadora de gonadotropinas y prostaglandina F2α para novillas de leche y de carne

Cited by 3 publications

References 28 publications

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves

Effects of delaying the removal of the intravaginal progesterone device by 24 h in the 5d Co-synch protocol in heifers

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

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