Timed artificial insemination: current challenges and recent advances in reproductive efficiency in beef and dairy herds in Brazil

Reproductive efficiency is closely tied to the profitability of dairy herds, and therefore successful dairy operations seek to achieve high 21-day pregnancy rates in order to reduce the calving interval and days in milk of the herd. There are various factors that impact reproductive performance, including the specific reproductive management program, body condition score loss and nutritional management, genetics of the cows, and the cow comfort provided by the facilities and management programs. To achieve high 21-day pregnancy rates, the service rate and pregnancy per artificial insemination (P/AI) should be increased. Currently, there are adjustments in timed artificial insemination (TAI) protocols and use of presynchronization programs that can increase P/AI, even to the point that fertility is higher with some TAI programs as compared with AI after standing estrus. Implementation of a systematic reproductive management program that utilizes efficient TAI programs with optimized management strategies can produce high reproductive indexes combined with healthy cows having high milk production termed “the high fertility cycle”. The scientific results that underlie these concepts are presented in this manuscript along with how these ideas can be practically implemented to improve reproductive efficiency on commercial dairy operations.

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PSVIII-16 Effect of estrous synchronization with natural service or fixed-timed artificial insemination with conventional or gender-skewed semen in beef females

Journal of Animal Science ◽

10.1093/jas/skab235.773 ◽

2021 ◽

Vol 99 (Supplement_3) ◽

pp. 431-432

Author(s):

Julie Walker ◽

George A Perry ◽

Jerica J Rich

Keyword(s):

Artificial Insemination ◽

Reproductive Efficiency ◽

Weaning Weight ◽

Estrous Synchronization ◽

Sexed Semen ◽

Group A ◽

Timed Artificial Insemination ◽

Calving Season ◽

And Gender ◽

Natural Service

Abstract Reproductive efficiency is critical for profitability, and age at weaning critically impacts weaning weight. The objective was to evaluate estrous synchronization and/or AI with conventional (CON) or gender-skewed (SEXED) semen on calving distribution. Beef females (n=1,620) were either 1) synchronized (7-CIDR:Syn) or not synchronized (Nonsyn) and mated to bulls, 2) synchronized (7-d CIDR) and mated to bulls (SynNS) or artificially inseminated (SynAI), or 3) synchronized (7-d CO-Synch plus CIDR) and AIed with CON or SEXED semen. Calving distribution and gender were determined at birth and were analyzed using the GLIMMIX procedure in SAS. Synchronization resulted in more calves born from d1 to 14 (P < 0.01; 62% vs 47%) of the calving season. There was no differences (P = 0.31) between Syn and Nonsyn in the percent of calves born after d21, but between d22 and 42, more (P = 0.04) calves were born in the Nonsyn group. A greater proportion (P < 0.02; 46% vs 38%) of calves were born in SynNS between d1 and 14 compared to SynAI. There was no difference between treatments (P > 0.12) from d1 to 42, but more calves were born for SynAI after d43. With SEXED semen, there were no differences (P > 0.14) between CON and SEXED for the proportion of calves born from d1 to 14 or d1 to 21; however, more of the desired gender were born in the SEXED group during d1 to 14 of the calving season (P < 0.01; 84% vs 68%). More total calves were born from d22 to 42 in the SEXED group compared to the CON group (P < 0.05; 49% vs 33%). In summary, synchronization increased the proportion of females that calved early in the calving season, and SEXED semen increased the proportion of the desired gender born early in the calving season.

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