Thermal Mechanisms Preventing or Favoring Multiple Ovulations in Dairy Cattle

Rensis, F. De; Morini, G.; García-Ispierto, Irina; López‐Gatius, F.

doi:10.3390/ani11020435

Cited by 4 publications

(4 citation statements)

References 58 publications

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“…In the latter study, the unilateral/bilateral multiple pregnancy ratio varied from 1.07 (346/323) during the cool period to 1.4 (269/192) during the warm period [ 74 ]. In other words, a ratio between unilateral and bilateral multiple pregnancies close to one may be a good indicator of cow well-being and absence of HS in dairy herds [ 75 ].…”

Section: Discussionmentioning

confidence: 99%

Effects of Heat Stress on Follicular Physiology in Dairy Cows

Rensis

Saleri

García-Ispierto

et al. 2021

Animals

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Follicular organization starts during mid-to-late fetal life with the formation of primordial follicles. The bilateral interplay between the oocyte and adjoining somatic cells during follicular growth and ovulation may be sensitive to heat stress (HS). Mechanisms giving rise to pre-ovulatory temperature gradients across reproductive tissues are mostly regulated by the pre-ovulatory follicle, and because the cooling of the gonads and genital tract depends on a counter-current transfer system of heat, HS may be considered a major factor impairing ovulation, fertilization and early embryo development. There is evidence of a long-lasting influence of HS on oogenesis and final follicular maturation. Follicular stages that are susceptible to HS have not been precisely determined. Therefore, the aim of this review was to describe the influence of HS during the staged follicular development in dairy cattle, from the activation of primordial follicles to ovulation. Some clinical prospects are also considered.

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Section: Discussionmentioning

confidence: 99%

Effects of Heat Stress on Follicular Physiology in Dairy Cows

Rensis

Saleri

García-Ispierto

et al. 2021

Animals

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“…A further expected result was the low incidence (4.5%) of bilateral dead twins during the late embryonic period. Under good management and environmental conditions, the ratio between unilateral and bilateral multiple pregnancies is normally close to one [ 34 ]. Here, the ratio was 21.2 (95.5/4.5), indicating a clear predominance of dead unilateral twins upon the first pregnancy diagnosis 28–34 days post-AI.…”

Section: Discussionmentioning

confidence: 99%

Response to Therapeutic Abortion in Lactating Dairy Cows Carrying Dead Twins during the Late Embryo/Early Fetal Period

López‐Gatius

2021

Animals

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This study examined the dose–response effect of prostaglandin F2α (PGF2α) when used to induce abortion in cows with two dead twins at pregnancy diagnosis 28–34 days post-AI (late embryonic period: LE) or at pregnancy confirmation 49–55 days post-AI (early fetal period: EF). The study population consisted of 415 cows receiving a single PGF2α dose (PG1 group: 254 LE and 161 EF cows) and 200 receiving a 1.5 × PGF2α dose (PG1.5 group: 121 LE and 79 EF cows). The induced abortion rate was significantly lower (chi-square test; p < 0.0001) in the EF (34.6%) than LE cows (88%), and was also reduced (p = 0.001) in the EF PG1 group (28%) compared with the EF PG1.5 group (48.1%). High milk production (≥45 kg) was the only factor influencing the induced abortion rate in LE cows (odds ratio 0.2; p < 0.0001), whereas the odds ratio for induced abortion of PG1.5 cows was 2.3 (p = 0.005) in EF cows. In conclusion, an increased PGF2α dose had no effect on abortion induction during the late embryonic period and its rate was inversely associated with milk production. This higher PGF2α dose did, however, offer benefits during the early fetal period.

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“…Although some economic gain has been reported for twin pregnancies, the losses generally outweigh the gains, with an average $135 loss for twin pregnancies compared with singletons in dairy cattle (Cabrera and Fricke, 2021). The economic losses from twin calving in cattle have multiple explanations, including a 3-to 9-fold greater risk of pregnancy loss (Silva-Del-Río et al, 2009;López-Gatius et al, 2017), particularly during heat stress or if both pregnancies are in the same uterine horn (Garcia-Ispierto and López-Gatius, 2019;De Rensis et al, 2021). Other explanations include a greater frequency of dystocia, freemartins, retained placenta, and calf mortality, as well as an increased number of days open and decreased fertility (Echternkamp and Gregory, 1999;Andreu-Vázquez et al, 2012a).…”

Section: Introductionmentioning

confidence: 99%

Effect of elevating luteinizing hormone action using low doses of human chorionic gonadotropin on double ovulation, follicle dynamics, and circulating follicle-stimulating hormone in lactating dairy cows

Gomez-León

Beard

Ginther

et al. 2022

Journal of Dairy Science

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Double ovulation and twin pregnancy are undesirable traits in dairy cattle. Based on previous physiological observations, we tested the hypothesis that increased LH action [low-dose human chorionic gonadotropin (hCG)] before the expected time of diameter deviation would change circulating FSH concentrations, maximum size of the second largest (F2) and third largest (F3) follicles, and frequency of multiple ovulations in lactating dairy cows with minimal progesterone (P4) concentrations. In replicate 1, multiparous, nonbred lactating Holstein dairy cows (n = 18) had ovulation synchronized. On d 5 after ovulation, all cows had their corpus luteum regressed and were submitted to follicle (≥3 mm) aspiration 24 h later to induce emergence of a new follicular wave. Cows were then randomized to NoP4 (untreated) and NoP4+hCG (100 IU of hCG every 24 h for 4 d after follicle aspiration). Ultrasound evaluations and blood sample collections were performed every 12 h for 7 d after follicle aspiration. All cows were then treated with 200 μg of GnRH to induce ovulation. In replicate 2, cows (n = 16) were resubmitted to similar procedures (i.e., corpus luteum regression, follicle aspiration, randomization, ultrasound evaluations every 12 h, GnRH 7 d after aspiration). However, cows in replicate 2 received an intravaginal P4 device that had been previously used (~18 d). Only cows with single (n = 15) and double (n = 16) ovulations were used in the analysis. No significant differences were detected for frequency of double ovulation, follicle sizes, and FSH concentrations across replicates (NoP4 vs. LowP4 and NoP4+hCG vs. LowP4+hCG), so data were combined. Double ovulation was 40% for control cows with no hCG (CONT) and 62.5% with hCG (hCG). Double ovulation increased as the maximum size of F2 increased: <9.5 mm and 9.5-11.5 mm (7.7%) and ≥11.5 mm (94.1%). The hCG group had more cows with F2 > 11.5 (69%) than with 9.5 ≥ F2 ≤ 11.5 (25%) and F2 < 9.5 (6%). In agreement, F2 and F3 maximum size were larger in the hCG group, but FSH concentrations were lower after F1 > 8.5 mm compared with CONT. In contrast, FSH concentrations were greater before deviation (F1 closest value to 8.5 mm) in cows with double ovulations than in those with single ovulations, regardless of hCG treatment. In addition, time from aspiration to deviation was shorter in cows with double rather than single ovulation and in cows treated with hCG as a result of faster F1, F2, and F3 growth rates before diameter deviation. In conclusion, greater FSH and follicle growth before deviation seems to be a primary driver of greater frequency of double ovulation in lactating cows with low circulating P4. Moreover, the increase in follicle growth before deviation and in the maximum size of F2 during hCG treatment suggests that increased LH may also have a role in stimulating double ovulation.

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Thermal Mechanisms Preventing or Favoring Multiple Ovulations in Dairy Cattle

Cited by 4 publications

References 58 publications

Effects of Heat Stress on Follicular Physiology in Dairy Cows

Effects of Heat Stress on Follicular Physiology in Dairy Cows

Response to Therapeutic Abortion in Lactating Dairy Cows Carrying Dead Twins during the Late Embryo/Early Fetal Period

Effect of elevating luteinizing hormone action using low doses of human chorionic gonadotropin on double ovulation, follicle dynamics, and circulating follicle-stimulating hormone in lactating dairy cows

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