Figure 1
Seasonal variation in characteristics of estrus in lactating cows. Shown are data on duration of estrus in Arizona (Wolff and Monty, 1974Wolff LK, Monty DE, Jr. 1974. Physiologic response to intense summer heat and its effect on the estrous cycle of nonlactating and lactating Holstein-Friesian cows in Arizona. Am J Vet Res, 35:187-192.), number of mounts per estrus in Virginia (Nebel et al., 1997Nebel RL, Jobst SM, Dranfield MBG, Pandolfi SM, Bailey, TL. 1997. Use of radio frequency data communication system, HeatWatch®, to describe behavioral estrus in dairy cattle. J Dairy Sci. 80 (Suppl. 1):179 (Abstract).), the increase in pedometer activity at estrus in Spain (López-Gatius et al., 2005aLópez-Gatius F, Santolaria P, Mundet I, Yániz JL. 2005a. Walking activity at estrus and subsequent fertility in dairy cows. Theriogenology, 63:1419-1429.) and estimated percent of estrus periods detected by farm personnel in Florida (Thatcher et al., 1986). The figure is reproduced from Hansen (2017)Hansen PJ. 2017. Physiological approaches to improving fertility during heat stress. In Large Herd Dairy Management, 3rd. ed., Beede, D.K. (ed.), American Dairy Science Assn, Champaign-Urbana, Illinois, chapter 7-24. with permission of the American Dairy Science Association.
Figure 2
Pregnancies per artificial insemination of herds surveyed in Israel (Flamenbaum and Galon, 2010Flamenbaum I, Galon N. 2010. Management of heat stress to improve fertility in dairy cows in Israel. J Reprod Dev, 56 (Suppl):S36-41.). Herds were classified based on the overall level of milk production (high vs low) and on the degree of cooling that cows receive (intensive vs moderate).
Figure 3
Comparisons of pregnancy success for artificial insemination vs embryo transfer in the summer. Data are from Putney et al. (1989b)Putney DJ, Drost M, Thatcher WW. 1989b. Influence of summer heat stress on pregnancy rates of lactating dairy cattle following embryo transfer or artificial insemination. Theriogenology, 31:765-778. (A), Drost et al. (1999)Drost M, Ambrose JD, Thatcher MJ, Cantrell CK, Wolfsdorf KE, Hasler JF, Thatcher WW. 1999. Conception rates after artificial insemination or embryo transfer in lactating dairy cows during summer in Florida. Theriogenology, 52:1161-1167. (B), Stewart et al. (2011)Stewart BM, Block J, Morelli P, Navarette AE, Amstalden M, Bonilla L, Hansen PJ, Bilby TR. 2011. Efficacy of embryo transfer in lactating dairy cows during summer using fresh or vitrified embryos produced in vitro with sex-sorted semen. J Dairy Sci, 94:3437-3445. (C), Vasconcelos et al. (2011)Vasconcelos JL, Jardina DT, Sá Filho OG, Aragon FL, Veras MB. 2011. Comparison of progesterone-based protocols with gonadotropin-releasing hormone or estradiol benzoate for timed artificial insemination or embryo transfer in lactating dairy cows. Theriogenology, 75:1153-1160. (D) and Baruselli et al. (2011)Baruselli PS, Ferreira RM, Sales JN, Gimenes LU, Sá Filho MF, Martins CM, Rodrigues CA, Bó GA. 2011. Timed embryo transfer programs for management of donor and recipient cattle. Theriogenology, 76:1583-1593. (E). Abbreviations are as follows: AI, artificial insemination, ET, embryo transfer; IVF, in vitro fertilized; SO, superovulation; TAI, timed AI; TET, timed embryo transfer; Vit., vitrified. The figure is modified from a technical bulletin by Vetoquinol and is reproduced with permission.
Figure 4
Comparisons of percent cows pregnant following embryo transfer in cool or hot weather. Data are from Putney et al. (1988b)Putney DJ, Thatcher WW, Drost M, Wright JM, DeLorenzo MA. 1988b. Influence of environmental temperature on reproductive performance of bovine embryo donors and recipients in the southwest region of the United States. Theriogenology, 30:905-922. (A), Block et al. (2007) and Loureiro et al. (2009)Loureiro B, Bonilla L, Block J, Fear JM, Bonilla AQ, Hansen PJ. 2009. Colony-stimulating factor 2 (CSF-2) improves development and posttransfer survival of bovine embryos produced in vitro. Endocrinology, 150:5046-5054. (B), Ferraz et al. (2016)Ferraz PA, Burnley C, Karanja J, Viera-Neto A, Santos JE, Chebel RC, Galvão KN. 2016. Factors affecting the success of a large embryo transfer program in Holstein cattle in a commercial herd in the southeast region of the United States. Theriogenology, 86:1834-1841. (C), Chebel et al. (2008)Chebel RC, Demétrio DG, Metzger J. 2008. Factors affecting success of embryo collection and transfer in large dairy herds. Theriogenology, 69:98-106. (D), Vasconcelos et al. (2011)Vasconcelos JL, Jardina DT, Sá Filho OG, Aragon FL, Veras MB. 2011. Comparison of progesterone-based protocols with gonadotropin-releasing hormone or estradiol benzoate for timed artificial insemination or embryo transfer in lactating dairy cows. Theriogenology, 75:1153-1160. (E) and Baruselli et al. (2011)Baruselli PS, Ferreira RM, Sales JN, Gimenes LU, Sá Filho MF, Martins CM, Rodrigues CA, Bó GA. 2011. Timed embryo transfer programs for management of donor and recipient cattle. Theriogenology, 76:1583-1593. (F). Abbreviations are as follows: ET, embryo transfer; IVF, in vitro fertilized; S. Dakota, South Dakota; Spr., spring; SO, superovulation; Sum., summer; TET, timed embryo transfer; THI, temperature-humidity index; Win., winter. The figure is modified from a technical bulletin by Vetoquinol and is reproduced with permission.