Spotlight - male livestock reproductive health

Successful livestock breeding usually focusses considerable attention on readying females of breeding age. Almost forgotten, some males’ breeding preparation can languish in the shadows prior to mating, and yet still be expected to perform optimally for a fruitful union. Male infertility and suboptimal fertility can be important contributing factors of poor pregnancy rates in New Zealand livestock. Good can transform into best, simply by utilising key basic factors to help livestock sires shine. Breeding sire preparation should begin at least two months prior to mating, including a vet check assessment of physical and functional reproductive soundness, and to exclude disease. In ruminants, scrotal circumference is a positive indicator and genuine measurement of fertility. Provide any necessary vaccinations such as ‘Multine 5-in-1’ to aid against clostridial disease occurring consequent to fighting injuries.

Having reasonable body condition, health and reproductive function for mating, begins months before breeding season through feeding a balanced diet, allowing for gradual weight gain and high-quality sperm production to ensue. Protein and energy play key roles in reproductive performance, both during pre-pubertal development and long-term seasonal performance, leading to higher conception rates and more progeny born. On the first day of breeding, a sire will be utilising semen produced almost two months previously, due to the length of time required for the completion of sperm maturation in the epididymis. Minimising heat stress over this period is also important – shearing full fleece rams is advisable to minimise overheating and impairment of semen quality. Integral to optimal male fertility and the production of male hormones, healthy motile sperm with normal morphology and functionality, and libido are trace minerals including zinc, selenium, copper, and manganese. High levels of dietary antagonists like iron, sulphur, or molybdenum can exacerbate some trace mineral deficiencies. Trace minerals can be supplemented via diet, poured mineral blocks, and direct administration of oral or injectable products, such as Injectamin or Injectamax.

However, due to only being required in minute amounts, care must be exercised to avoid over-supplementation of trace minerals, which can lead to reduced fertility and even toxicity. Regular testing of trace mineral levels in animals’ blood and liver on-farm is advisable to best support the trace mineral requirements of breeding sires. For rams, warmer weather brings an increased risk of flystrike from fighting and head-butting other rams for dominance. Flystrike is a welfare issue and prompt treatment is required. Preventative applications of effective flystrike products mitigate the risk, but ongoing monitoring is still necessary to ensure no rams become flystruck. Proper sire management is essential to avert over-work and reduced sire fertility, and for attaining expected pregnancy rates. Do not forget to join males with females. Yes, it has happened. Switch and rotate sires during the season to help safeguard any sire underperforming and help maintain condition. Livestock breeding is commonly cyclic and seasonal, which is why enjoying the fruit of a compact breeding season is not merely by chance or opportunistic but influenced by good practices. This not only aids planning for spring feed needs, but it can also significantly impact an individual’s lifetime reproductive proficiency and profitable economic returns.