Poor reproductive performance is in the top three challenges on dairy farms (Denis-Robichaud et al., 2018). High producing dairy cattle often have low fertility due to a variety of factors including genetic selection, on-farm management, health status and nutrition. Though progress has been made in genetic selection to improve fertility and more research is available on proper management of the post-partum cow, there are still a number of factors that can cause reduced fertility in dairy cows. These factors include delayed resumption of normal cyclicity and proper uterine health following parturition, as well as lower expression of estrus and lower survivability of embryos (Crowe et al., 2018).
Trace mineral nutrition can have an impact on each of factors above as they support reproductive performance. Understanding the role that three critical trace minerals - manganese, zinc, and copper - play in supporting fertility in dairy cattle demonstrates the need to ensure dairy cattle are supplied adequate levels of trace minerals.
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Manganese is needed for steroid
synthesis including key reproductive steroids, progesterone, estrogen, and
testosterone (Keen and Zidenburg-Cherr, 1990). Improper manganese levels can
lead to decreased circulation of these key hormones resulting in anestrus or
irregular estrus lowering conception rates (Bhalakiya et al., 2019). Manganese has a role in initiating estradiol secretion by the conceptus as a pregnancy
recognition signal (Hostetler et al., 2003). Having adequate manganese will contribute
to proper hormone levels required for resumption of normal cyclicity that
results in greater fertility.
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Zinc is needed for maintenance and
repair of the uterine epithelium, while also being involved in ovarian follicle
recognition and fetal growth. Adequate zinc is needed to allow the oocyte,
an immature egg, to mature into an egg ready for fertilization
through improving the quality of the egg (Garner et al., 2021). Once the egg
has been fertilized, the egg needs to develop properly. Zinc helps maintain
symmetrical division and supports proper cellular proliferation and
differentiation of the embryo (Garner et al., 2021). This will hopefully result
in greater embryo quality and survivability that translates to more pregnant
cows.
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Copper deficiencies have been linked
to delayed onset of puberty, low conception rates, and the need for repeat
breeding. This demonstrates the need to supplement the proper level of copper
in dairy rations. Copper has been shown to assist not only in fertility of the
cow but also to benefit the developing fetus. Copper is stored at a
much higher level per unit of body mass in the fetus compared to an adult cow
(Michaluk and Kochman, 2007). With the fetus being highly dependent on copper
supply from the dam, maternal copper supply is critical during the second and
third trimesters of pregnancy and plays a key role in fetal development
(Michaluk and Kochman, 2007).
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Research where manganese, zinc, and copper were supplied in the form of MINTREX® bis-chelated trace minerals resulted in improved conception rates (Zanton et al., 2011; Bach et al., 2015).
A trial was conducted at a New York dairy trial facility across a 305-day period. The
trial had 4 pens (~50 cows per pen) arranged between 2 treatments, a Control diet
with ITMs and a treatment diet using REDUCE AND REPLACE™ with MINTREX®. Cows fed MINTREX® were 1.6 times more likely to conceive at earlier
services compared to Control cows (Zanton et al., 2011).
A 6-month study on 27 dairy herds with 2,880 cows fed a total
mixed ration from a common mixing site was conducted through the
IRTA dairy cooperative in Spain. There were 15 herds (1,287 cows)
fed inorganic trace minerals (ITMs) and 12 herds (1,593 cows) fed a
combination of ITMs and MINTREX® trace minerals. Reproductive performance was monitored
for each herd using the month prior to the study as a baseline. Cows fed MINTREX® were 1.5 times more likely to conceive at first service compared to cows fed ITMs (Bach et al., 2015).
These trials support the role of manganese, zinc, and copper in boosting fertility in lactating dairy cattle. Supplementing with MINTREX® trace minerals provides a more bioavailable mineral, so more mineral is absorbed and available for the cow to use for production purposes like fertility.
References
Bach, A., A. Pinto, and M. Blanch. 2015. Association between chelated trace mineral supplementation and milk yield, reproductive performance, and lameness in dairy cattle. Liv. Sci. 182:69-75. Doi:10.1016/j/livsci.2015.10.023.
Bhalakiya, N., N. Haque, P. Patel, and P. Joshi. 2019. Role of trace minerals in animal production and reproduction. Int. J. Livest. Res. 9: 1-12. Doi: 10.5455/ijlr.20190222105609.
Crowe, M. A., M. Hostens, and G. Opsomer. 2018. Reproductive management in dairy cows- the future. Ir. Vet. J. 71: 1-13. Doi: 10.1186/s13620-017-0112-y.
Denis-Robichaud, J., R. L. A. Cerri, A. Jones-Bitton, and S. J. LeBlanc. 2018. Dairy producers’ attitudes toward reproductive management and performance on Canadian dairy farms. K. Dairy Sci. 101: 850-860. Doi: 10.3168/jds.2016-12416.
Garner, T. B., J. M. Hester, A. Carothers, and F. J. Diaz. 2021. Role of zinc in female reproduction. Biol. Reprod. 104: 976-994. Doi: 10.1093/biolre/ioab023
Hostetler, C. E., R. L. Kincaid, and M. A. Mirando. 2003. The role of essential trace elements in embryonic and fetal development in livestock. Vet. J. 166: 125-139. Doi: 10.1016/S1090-0233(02)00310-6
Keen, C. L., and S. Zidenberg-Cheer. 1990. Manganese. Present knowledge in nutrition. 268-279. M. L. Brown (Ed.) International Life Science Institute Nutrition Foundation, Washington D.C.
Michaluk, A., and K. Kochman. 2007. Involvement of copper in female reproduction. Reprod. Biol. 7: 193-205.
Zanton, G. I., D. E. Diaz, M. Vazquez-Anon, and J. E. Nocek. 2011. Form of trace mineral supplementation on complete lactation performance, reproduction, and locomotion in Holstein cows. J. Dairy Sci. 94: 123 (Abstract).