Acknowledgement
The authors thank the owners and all employees of Fazenda Mater for the use of their facilities and help with animal management. CAPES for scholarship support (first author). Minerthal supported this research.
References
- D'Occhio MJ, Baruselli PS, Campanile G. Metabolic health, the metabolome and reproduction in female cattle: a review. Ital J Anim Sci 2019;18:858-67. https://doi.org/10.1080/1828051X.2019.1600385
- Wiltbank JN, Rowden WW, Ingalls JE, Geegoey KE, Koch RM. Effect of energy level on reproductive phenomena of mature hereford cows. J Anim Sci 1962;21:219-25. https://doi.org/10.2527/jas1962.212219x
- Santos FP, Dorea JR, Costa DFA, De Souza J, Batistel F. Forage management and methods to improve nutrient intake in grazing cattle. The 25th Symposium Nutrition Symposium; Gainesville, FL, United States, 4-5 February 2014. Gainesville, FL USA: University of Florida; 2014. pp. 144-65.
- De Gouvea VN, Colli MHA, Goncales Junior WA, et al. The combination of β-carotene and vitamins improve the pregnancy rate at first fixed-time artificial insemination in grazing beef cows. Livest Sci 2018;217:30-6. https://doi.org/10.1016/j.livsci.2018.09.002
- Stobbs TH. Factors limiting the nutritional value of grazed tropical pastures for beef and milk production. Trop Grasslands 1975;9:141-50.
- Sotelo D, Paulino MF, Renno LN, et al. Performance and metabolic status of grazing beef heifers receiving increasing protein supplementation pre- and postpartum. Anim Prod Sci 2018;59:1244-52. https://doi.org/10.1071/AN17485
- Spitzer JC, Morrison DG, Wettemann RP, Faulkner LC. Reproductive responses and calf birth and weaning weights as affected by body condition at parturition and postpartum weight gain in primiparous beef cows. J Anim Sci 1995;73:1251-7. https://doi.org/10.2527/1995.7351251x
- Hess BW, Lake SL, Scholljegerdes EJ, et al. Nutritional controls of beef cow reproduction. J Anim Sci 2005;83(Suppl 13):E90-106. https://doi.org/10.2527/2005.8313_supplE90x
- Ayres H, Ferreira RM, Torres-Junior JRS, et al. Inferences of body energy reserves on conception rate of suckled Zebu beef cows subjected to timed artificial insemination followed by natural mating. Theriogenology 2014;82:529-36. https://doi.org/10.1016/j.theriogenology.2014.04.026
- Wettemann RP, Lents CA, Ciccioli NH, White FJ, Rubio I. Nutritional- and suckling-mediated anovulation in beef cows. J Anim Sci 2003;81(Suppl 2):E48-59. https://doi.org/10.2527/2003.8114_suppl_2E48x
- De Moura FH, Costa TC, Trece AS, et al. Effects of energyprotein supplementation frequency on performance of primiparous grazing beef cows during pre and postpartum. Asian-Australas J Anim Sci 2020;33:1430-43. https://doi.org/10.5713/ajas.19.0784
- Sales JNS, Bottino MP, Silva LACL, et al. Effects of eCG are more pronounced in primiparous than multiparous Bos indicus cows submitted to a timed artificial insemination protocol. Theriogenology 2016;86:2290-5. https://doi.org/10.1016/j.theriogenology.2016.07.023
- DelCurto T, Hess BW, Huston JE, Olson KC. Optimum supplementation strategies for beef cattle consuming lowquality roughages in the western United States. J Anim Sci 2000;77(Suppl E):1-16. https://doi.org/10.2527/jas2000.77esuppl1v
- Kunkle WE, Johns JT, Poore MH, Herd DB. Designing supplementation programs for beef cattle fed forage-based diets. J Anim Sci 2000;77(Suppl E):1-12. https://doi.org/10.2527/jas2000.00218812007700es0012x
- Meteer WC, Shike DW, De Cardoso FC. Prepartum and postpartum nutritional management to optimize fertility in beef cattle. Acta Sci Vet 2015;43:1286.
- D'Occhio MJ, Baruselli PS, Campanile G. Influence of nutrition, body condition, and metabolic status on reproduction in female beef cattle: a review. Theriogenology 2019;125: 277-84. https://doi.org/10.1016/j.theriogenology.2018.11.010
- Bailey CR, Goetsch AL, Hubbell DS, Rosenkrans CF. Effects of monensin on beef cow reproduction. Can J Anim Sci 2008; 88:113-5. https://doi.org/10.4141/CJAS07082
- Hardin DR, Randel RD. Effect of monensin on postpartum interval to first estrus and serum LH response to 0, 1, 2 or 4 mg estradiol-17β at 21 days postpartum. Theriogenology 1983;19:343-54. https://doi.org/10.1016/0093-691X(83)90090-0
- Cassini MH, Hermitte G. Patterns of environmental use by cattle and consumption of supplemental food blocks. Appl Anim Behav Sci 1992;32:297-312. https://doi.org/10.1016/S0168-1591(05)80023-1
- Bailey DW, Welling GR. Evaluation of low-moisture blocks and conventional dry mixes for supplementing minerals and modifying cattle grazing patterns. Rangel Ecol Manag 2007;60:54-64. https://doi.org/10.2111/05-138R1.1
- Loest CA, Titgemeyer EC, Drouillard JS, Lambert BD, Trater AM. Urea and biuret as nonprotein nitrogen sources in cooked molasses blocks for steers fed prairie hay. Anim Feed Sci Technol 2001;94:115-26. https://doi.org/10.1016/S0377-8401(01)00312-1
- Moriel P, Vendramini JMB, Carnelos C, Piccolo MB, da Silva HM. Effects of monensin on growth performance of beef heifers consuming warm-season perennial grass and supplemented with sugarcane molasses. Trop Anim Health Prod 2019;51:339-44. https://doi.org/10.1007/s11250-018-1693-5
- Valadares Filho S de C, Silva LFC e, Gionbelli MP, et al. Nutrient requirements of Zebu and crossbred cattle - BR-CORTE. In: Suprema Grafica, editor. Exig. Nutr. Zebuinos Puros e Cruzados - BR-CORTE, Editora Federal de Vicosa; 2016. https://doi.org/10.5935/978-85-8179-111-1.2016B002
- Ayres H, Ferreira RM, de Souza Torres-Junior JR, Demetrio CGB, de Lima CG, Baruselli PS. Validation of body condition score as a predictor of subcutaneous fat in Nelore (Bos indicus) cows. Livest Sci 2009;123:175-9. https://doi.org/10.1016/j.livsci.2008.11.004
- Shoup LM, Kloth AC, Wilson TB, et al. Prepartum supplement level and age at weaning: I. Effects on pre- and postpartum beef cow performance and calf performance through weaning. J Anim Sci 2015;93:4926-35. https://doi.org/10.2527/jas.2014-8564
- Vizcarra JA, Wettemann RP, Spitzer JC, Morrison DG. Body condition at parturition and postpartum weight gain influence luteal activity and concentrations of glucose, insulin, and nonesterified fatty acids in plasma of primiparous beef cows. J Anim Sci 1998;76:927-36. https://doi.org/10.2527/1998.764927x
- Williams AR. Ultrasound applications in beef cattle carcass research and management. J Anim Sci 2002;80(Suppl 2):E183-8. https://doi.org/10.2527/animalsci2002.80E-Suppl_2E183x
- Marques RS, Cooke RF, Rodrigues MC, Moriel P, Bohnert DW. Impacts of cow body condition score during gestation on weaning performance of the offspring. Livest Sci 2016; 191:174-8. https://doi.org/10.1016/j.livsci.2016.08.007
- Schelling GT. Monensin mode of action in the rumen. J Anim Sci 1984;58:1518-27. https://doi.org/10.2527/jas1984.5861518x
- Reed BK, Whisnant CS. Effects of monensin and forage: concentrate ratio on feed intake, endocrine, and ovarian function in beef heifers. Anim Reprod Sci 2001;67:171-80. https://doi.org/10.1016/S0378-4320(01)00118-X
- Matos M. Monensin supplementation pre and postpartum associated synchronization of the ovulation protocols in nelore cows. Dissertation, 2004, 58 f.
- Laskowski D, Sjunnesson Y, Humblot P, Andersson G, Gustafsson H, Bage R. The functional role of insulin in fertility and embryonic development-What can we learn from the bovine model? Theriogenology 2016;86:457-64. https://doi.org/10.1016/j.theriogenology.2016.04.062
- Wettemann RP, Bossis I. Energy intake regulates ovarian function in beef cattle. J Anim Sci 2000;77(Suppl E):1-10. https://doi.org/10.2527/jas2000.77e-suppl1c
- Sa Filho MF, Penteado L, Reis EL, Reis TANPS, Galvao KN, Baruselli PS. Timed artificial insemination early in the breeding season improves the reproductive performance of suckled beef cows. Theriogenology 2013;79:625-32. https://doi.org/10.1016/j.theriogenology.2012.11.016
- Baruselli PS, Ferreira RM, Sa Filho MF, Bo GA. Review: Using artificial insemination v. natural service in beef herds. Animal 2018;12:s45-52. https://doi.org/10.1017/S175173111800054X
- Freitas BG, Mingoti RD, Monteiro BM, et al. Relationship of body maturation with response to estrus synchronization and fixed-time AI in Nelore (Bos indicus) heifers. Livest Sci 2021;251:104632. https://doi.org/10.1016/j.livsci.2021.104632
- Callaghan MJ, Rodgers RJ, Perry VEA. Supplementation of rangeland primiparous Bos indicus x Bos taurus beef heifers during lactation. 1. Effects on dam milk production and liveweight, bull calf growth, live carcass characteristics and metabolic hormone concentrations. Theriogenology 2020; 152:69-82. https://doi.org/10.1016/j.theriogenology.2020.04.030
- Bohnert DW, Stalker LA, Mills RR, Nyman A, Falck SJ, Cooke RF. Late gestation supplementation of beef cows differing in body condition score: Effects on cow and calf performance. J Anim Sci 2013;91:5485-91. https://doi.org/10.2527/jas.2013-6301
- Hill SL, Olson KC, Jaeger JR, Stevenson JS. Serum and plasma metabolites associated with postpartum ovulation and pregnancy risks in suckled beef cows subjected to artificial insemination. J Anim Sci 2018;96:258-72. https://doi.org/10.1093/jas/skx033
- Rhoads ML, Rhoads RP, Gilbert RO, Toole R, Butler WR. Detrimental effects of high plasma urea nitrogen levels on viability of embryos from lactating dairy cows. Anim Reprod Sci 2006;91:1-10. https://doi.org/10.1016/j.anireprosci.2005.02.009
- Gunn PJ, Lundberg AL, Cushman RA, Freetly HC, Amundson OL. Effect of circulating blood or plasma urea nitrogen concentrations on reproductive efficiency in beef heifers and cows. Iowa State University Animal Industry Report 13, Animal Industry Report: Volume 662, Issue 1. https://doi.org/10.31274/ans_air-180814-542