While nutritional management (especially in the springer period) plays a significant role in reproductive performance, it is not the only factor contributing to poor reproductive performance. A review of reproductive management in dairy cows1 showed that factors that reduced fertility include delayed cycling activity, uterine health, lower expression of heat symptoms and lower pregnancy rates to first and subsequent inseminations. The latter is mainly caused by an increased incidence of embryonic and foetal death.
Over the last 20 years genetic selection for high-yielding cows has led to an unconscious bias towards cows that mobilise their body reserves in early lactation. While most cows can cope with moderate ‘metabolic load’, excessive body weight loss results in metabolic stress. If left unchecked, this may result in a “shut down” of non-essential processes, such as immunity and fertility. Examples of metabolic stress or depressed immune function are uterine infections and elevated somatic cell count. Therefore, trace minerals (especially selenium, iodine and zinc) and vitamins (especially A, D and E) are very important during calving and mating. New tools such as Melofeed® (a world’s first primary antioxidant) are also useful tools to help reduce the impacts of metabolic stress on immune function and the developing embryos.
Rumensin® 20% Millmix and Rumensin® Trough Treatment have just been reclassified to a class 6.1C and 6.1D respectively. So you don’t need to be a Certified Handler to purchase it now.
In addition to supporting immune function, reducing the risk of ketosis is also critical for improving reproduction outcomes. There have been over 30 papers published containing 45 trials specifically on Rumensin® showing the effect of Rumensin® on metabolic disease.2 A common and consistent finding in these studies has been a decrease in blood concentrations of ‘ketosis markers’ known as BHBA or NEFA. On average Rumensin® decreases the risk of ketosis by 18-25%, and in some cases this reduction was as high as 50%.3 The benefit on reducing ketosis risk is greater in pasture fed herds as the risk of negative energy balance can be higher, especially in early lactation.
Other post calving strategies to help improve fertility include feeding diets designed to counteract the effects of negative energy
balance e.g., diets containing grain and their by-products should be fed immediately post caving. However, this presents its own set of challenges as cows that are poorly adapted to concentrates are less likely to eat because of sub-acute rumen acidosis (which also prevents them from fully utilising their feed.) Levucell®SC is a unique, patented, natural, rumen specific live yeast (Saccharomyces cerevisiae CNCM I-1077) that is specifically selected to optimise rumen performance.
Levucell SC® can be added to in-shed feeds and or TMR’s and has been proven to excel under rumen challenged environments with a 7:1 return on investment.
- Reproductive management in dairy cows – the future. Mark A. Crowe, Miel Hostens & Geert Opsomer
- Compton et al., (2015). Efficacy of controlled-release capsules containing monensin for the prevention of subclinical ketosis in pasture-fed dairy cows. New Zealand Veterinary Journal 63:5 249-253
- Duffield et al., (2008c). A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle Part 3. Health and Reproduction. Journal of Dairy Science 91 2328–2341.