Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

Mellado, Miguel; Treviño, Lucía M; Chávez, Marı́a Isabel; Véliz-Deras, Francisco Gerardo; Macías‐Cruz, Ulises; Avendaño‐Reyes, Leonel; García, José Eduardo

doi:10.1111/rda.14250

Cited by 3 publications

(3 citation statements)

References 48 publications

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“…A recent study of pregnancy loss in New Zealand compared with North American Holsteins showed a higher abortion rate in the latter genotype, with an interaction between parity and genotype (Garzón et al, 2022). Additionally, Melendez et al (2023) found lower late embryo mortality (32 to 53 days) in Holstein cows sired by Limousine, compared with Holstein sires.…”

Section: Risk Factors For Abortionmentioning

confidence: 97%

Invited review: Bovine abortion—Incidence, risk factors and causes

Mee

2023

Reprod Domestic Animals

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The true incidence of bovine abortion (42–260 days of gestation) is unknown because of under‐reporting. This is particularly true of the first half of gestation when most abortions occur. From research studies, it is estimated that the animal‐level incidence of abortion between day 45 and term is approximately 10%, being lower in suckler than in dairy cows. While wide variation exists in herd‐level incidence, up to 30%, it is estimated that less than 5% of farmers report high (>5%) observed abortion rates. Given these figures, veterinary practitioners and farmers tend to use investigation thresholds close to these values, ≥5 and ≥3%, respectively. Most of the risk factors for abortion are animal‐level factors (e.g. parity), but there are also herd‐level factors (e.g. enterprise type). Of the many risk factors for bovine abortion, only a small number are modifiable. While the causes of bovine abortion are often classified as noninfectious or infectious, in reality, this means diagnosis not reached (DNR) or infectious. Approximately 40% of abortions are diagnosed as infectious and the remaining 60% as DNR; DNR includes both infectious and noninfectious causes not diagnosed. Increasingly, genetic causes are being diagnosed and changes to current national genetic selection indices may be warranted. Of the infectious causes, Neospora caninum is now the most commonly diagnosed abortifacient internationally, followed by Trueperella pyogenes, BVDv and fungi. Both national eradication programmes and effective vaccination programmes can reduce the burden of some infectious abortifacients, but the control of sporadic, noninfectious and Neospora‐associated abortions remains challenging.

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Section: Risk Factors For Abortionmentioning

confidence: 97%

Invited review: Bovine abortion—Incidence, risk factors and causes

Mee

2023

Reprod Domestic Animals

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“…Melendez et al. (2023) reported a significant difference in late embryo mortality (32–53 days of gestation) in Holstein cows bred with either Holstein or Limousin semen (15.2% and 9.8%, respectively), and this result was attributed to hybrid vigor in the crossbred calf.…”

Section: Genetic Variability In Cattle Breeds For the Risk Of Abortio...mentioning

confidence: 99%

The role of genetic variability of the host on the resistance to Neospora caninum infection in cattle

Dinon,

Fiorani,

Campero

et al. 2024

Animal Genetics

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Neospora caninum is one of the most frequently diagnosed abortifacient pathogens in cattle. There is abundant genomic information about the parasite itself, but very little is known about the genetic variability of resistance in the most common intermediate host. The aim of this review was to compile all the available information about the genetic variability associated with the resistance to N. caninum both between and within cattle breeds. We systematically searched for published studies that investigated the influence of genetics of the host on the prevalence of N. caninum and risk of abortion. Beyond the potential confounding effects of feeding systems, management and animal density, some lines of evidence suggest that Holstein, the most popular breed for milk production, has a comparatively higher risk of abortion due to infections by N. caninum, whereas some beef breeds from Continental Europe seem to be more resistant. It is still not clear if different genetic mechanisms of resistance are involved in the two known routes of infection: postnatal ingestion of oocysts or transplacental transmission from the infected dam to the fetus. Genomic information associated with susceptibility to infection and risk of abortion in different cattle breeds is still scarce. The information reported here could be useful to identify new research alternatives and to define novel strategies to deal with this major problem of animal production.

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“…Additionally, the training of inseminators is a significant contribution to the successful commercial application of AI to dairy cattle breeding [ 12 , 13 ]. In consequence, inseminator training and improvements in the act of inseminating remain topics of great interest [ 14 , 15 , 16 , 17 ]. However, the correct detection of estrus remains a challenge [ 18 , 19 , 20 , 21 , 22 ] determining that some 20% of inseminations may be performed in pregnant cows [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Timing of Insemination at Spontaneous Estrus in Dairy Cattle

López‐Gatius¹

2022

Animals

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Cows show spontaneous estrus over 8–20 h but become refractory to the bull about 10–12 h before ovulation. This indicates that ovulation occurs 10–12 h after the end of estrus behavior, yet spermatozoa from the bull ejaculate need to undergo maturation and capacitation for 6 to 8 h in the female reproductive tract before they are capable of fertilization. Traditionally, the onset of estrus has been considered the best timing for artificial insemination (AI) in cattle, that is, 6 to 24 h from the first signs of estrus. However, recent findings suggest this interval should be reduced to 16 to 6 h before ovulation, bringing it closer to the end of estrus. In this review, the end of estrus rather than its onset is proposed as the best guide for AI timing in dairy cattle, and physiological indicators of late estrus are discussed such as relaxation of the intravaginal part of the uterus, a lower cervical mucus viscosity and a softer pre-ovulatory follicular consistency as simple cues indicating a cow is ready for service.

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Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

Cited by 3 publications

References 48 publications

Invited review: Bovine abortion—Incidence, risk factors and causes

Invited review: Bovine abortion—Incidence, risk factors and causes

The role of genetic variability of the host on the resistance to Neospora caninum infection in cattle

Revisiting the Timing of Insemination at Spontaneous Estrus in Dairy Cattle

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