Effects of fescue toxicosis on reproduction in livestock.

The research article studies the adverse effects of fescue toxicosis, a disease resulting from the consumption of a specific fungus-infected grass, on the reproductive health and overall productivity of livestock.

Objective of the Study

The study aims to explore the mechanisms responsible for fescue toxicosis, manifested as lower calf birth rates, retarded growth rates, delayed puberty onset, and dysfunctional corpora lutea in heifers. The research further investigates this adverse effect on the endocrine functioning in steers and ewes, as well as its impact on pregnant mares.

Fescue Toxicosis and Its Impact

• Fescue toxicosis originates from livestock consuming endophyte-infected tall fescue, causing a severe drop in animal productivity due to diminished reproductive efficiency, reduced weight gains and curtailed milk production.
• In cattle, the condition may worsen due to the retention of winter fur, increased susceptibility to high temperatures, and light intolerance, suggesting a significant disruption in their normal biological rhythm.
• Endocrine effects are also marked, with steers showing reduced prolactin and melatonin secretions and altered neurotransmitter metabolism in pivotal organs like the hypothalamus, pituitary, and pineal glands.
• Ewes affected by the condition had declined prolactin levels and increased intervals from the introduction of the ram to conception, indicating disrupted reproductive cycles.
• Pregnant mares also faced complications including prolonged gestation, unusually thick placentas, extra-large foals, difficult labor (dystocia), and (lack of milk post-birth agalactia).

Possible Cause of Fescue Toxicosis

• Through this research, Ergot peptide alkaloids produced by the endophyte have been suggested as the primary causal agents behind fescue toxicosis.
• These compounds act destructively in the animal body by reducing prolactin, increasing body temperatures, and inducing powerful vasoconstrictive effects.
• Neurohormonal imbalances involving prolactin and melatonin, coupled with limited blood flow to internal organs, may be the primary triggers for abnormal reproduction, growth, and maturation in livestock consuming endophyte-infected tall fescue.