Superior Reproductive Performance: Are You Overlooking These Factors?

Reproductive efficiency is the foundation of successful cattle production. Every day a cow fails to conceive over the recommended 90-day conception window has a significant financial impact. During the first 100 days of lactation, including peak milk production, cows have high nutrient requirements that can exceed what is provided in the diet. In addition, a concurrent metabolic disorder can exacerbate this nutrient gap—especially of trace minerals.

Trace minerals play a vital role in many bodily processes and their adequate supply affects many facets of cattle performance and health, including fertility, claw integrity, udder health, antioxidant status, and immune function. A deficiency or low availability of trace minerals can result in silent heat, reduced first service conception rates and, consequently, longer calving intervals, or poor semen quality.

Lameness is not only a welfare issue but also a major factor affecting the reproductive performance of cows. It is estimated claw disorders affect up to 75 % of cows in Europe. As many of these disorders are subclinical and not immediately associated with lameness, the problem may be underestimated by farmers.

The relationship between estrous expression and lameness has been well described, with a noted decrease in estrous duration and intensity when lameness is present. Lame cows are mounted less frequently and express less intense estrous cycles (Figure 1). Although lameness shortens estrous behavior, it does not appear to affect the frequency of estrus. However, the stress caused by claw problems can impair the immune system and increase susceptibility to other diseases.

Figure 1: The effect of lameness on days from calving to conception in dairy cows. Cows with moderate lameness (maximum locomotion score 2) took almost 13 days longer to conceive compared to non-lame cows (maximum locomotion score 1). Severely lame cows (maximum locomotion score ≥ 3) experienced a prolonged conception interval of almost 30 days more than cows that were not lame (maximum locomotion score 1). Different letters denote significant differences between LS-Means (p < 0.001). Fürst-Waltl et al., 2021.

Even cows in well-managed dairy herds using the latest mastitis control measures continue to have high rates of subclinical and clinical mastitis, especially during the first 90 days of lactation. Clinical mastitis is negatively correlated with reproduction due to altered estrus intervals and decreased luteal phase length.

Cows with clinical mastitis may have disruptions in normal physiology, including decreased luteinizing hormone pulsatility, lack of luteinizing hormone surge and estrous behavior, suppressed estradiol, and failure to ovulate. Clinical mastitis prior to first service may increase the number of days to first service as well as days open (Figure 2).

Figure 2: The influence of udder health on reproductive status. Cows with clinical or subclinical mastitis before first service had increased days to first service and increased interval from calving to conception compared to healthy control cows without mastitis (p < 0.05). Schrick et al., 2001.

During the transition period, dairy cows face tremendous physiological challenges that result in negative energy balance, impaired immunity, and oxidative stress, ultimately compromising postpartum fertility. High oxidative stress disrupts cellular functions through protein and lipid peroxidation, altered gene expression and cell signaling, which may contribute to or exacerbate the effects of metabolic stress on reproductive functions. Oxidative stress can also lead to defects in sperm, resulting in poor bull performance.

Zinc has important reproductive functions. Zinc deficiency has been reported to contribute to subfertility, prolonged postpartum period to onset of estrous cycles, placental retention, increased number of services per conception, and abortions in cattle.

Undoubtedly the most studied trace mineral, zinc plays an important role in immune response and disease resistance. Zinc deficiency can weaken the first line of defense—the skin. Because zinc is required for the synthesis and maturation of keratin, adequate zinc status has long been recognized as necessary for normal wound healing.

Zinc has been shown to promote lower somatic cell counts in lactating dairy cows. The keratin lining of the teat canal protects the teat from bacterial invasion. This lining is lost during the milking process, so keratin must be regenerated to maintain this protective barrier. As zinc is essential for keratin formation, this reflects the importance of this trace element in maintaining an effective epithelial barrier in the udder.

Nutrition also influences claw integrity and wear rate, as the claw horn is also composed of keratin. Specifically, zinc, copper, and manganese are known to be important in the development and maintenance of keratin, while copper and zinc are associated with claw hardness. In fact, inadequate zinc has been linked to impaired locomotion in dairy herds.

In addition to its importance in keratin formation, low manganese levels have been linked to prolonged estrus, silent heat, increased abortion rates and weak calves. Manganese is also essential for bone and connective tissue strength. Adequate manganese promotes strong bone and connective tissue development, which ensures proper leg conformation and claw position.

The biogenesis of connective tissues is dependent on copper as it is required for the cross-linking of collagen and elastin fibers. This makes copper important for the strength and elasticity of claw horn and connective tissues. Copper deficiency can also reduce conception rates and increase embryonic death and retained placenta—all of which have serious implications for fertility and reproduction in cattle.

Low selenium levels have been associated with retained placenta, increased incidence of metritis and ovarian cysts in cows. In addition, selenium supplementation has been shown to reduce the severity and duration of acute coliform mastitis as well as the rate of clinical mastitis.

The role of trace minerals in enzyme function has been extensively studied. Several enzymes in the antioxidant system contain trace minerals such as copper, zinc, manganese, and selenium that are essential for proper function. Dietary deficiencies of these trace elements significantly reduce antioxidant activities, resulting in oxidative damage.

Moreover, during periods of negative energy balance, trace element levels and antioxidant status may suffer. Antioxidant deficiency appears to have a long-term carry-over effect well into the preovulatory stage at the time of breeding, suggesting persistent cellular stress and oxidative damage.

It is important to balance oxidative damage and antioxidant defense in animals by optimizing dietary intake of trace minerals, especially during periods of stress. The optimal antioxidant status of the cow at breeding time supports preovulatory follicular physiology and maximizes the chance of successful pregnancy.

To provide nutritional value, trace minerals must be absorbed. Therefore, not only is it important to provide a source of trace minerals, especially in times of added stress, but the source of the trace minerals is also important.

Inorganic trace minerals are subject to antagonistic effects in the gut, resulting in inefficient absorption and increased excretion. Organic trace minerals—trace minerals bound to amino acids—are more stable and less susceptible to antagonisms and complex formation. This means better absorption.

Fertility Pack^® Cattle is specifically developed for fertility support of high-performance cattle. Fertility Pack^® Cattle contains highly bioavailable organically bound trace minerals combined with selenium and vitamin E that is easily added to the daily ration.

All the components in Fertility Pack^® Cattle are relevant for fertility. The blend of trace minerals supports high milk yield, low somatic cell counts, efficient response of the immune system, and optimized claw integrity.

The supply of manganese, zinc, copper, and selenium has a direct impact on the reproductive performance of breeding animals. Healthy cattle are those that have adequate trace mineral levels to meet the demands of high productivity as well as reproduction.

Only healthy cattle have an edge in fertility. Fertility Pack^® Cattle supports your cattle’s health status, improves udder and claw health, and contributes to a higher reproductive performance.

Fertility Pack^® Cattle is the key to better fertility!