Organic and inorganic selenium: III. Ewe and progeny performance

Area of Science:

• Animal Science
• Nutritional Biochemistry
• Reproductive Physiology

Background:

• Selenium (Se) is a vital micronutrient for sheep, crucial for lamb growth and survival.
• Se deficiency can negatively impact flock productivity and animal health.
• Understanding the effects of different Se forms and dosages is essential for optimizing sheep nutrition.

Purpose of the Study:

• To investigate the impact of varying chemical forms and dosages of selenium on ewe and progeny performance.
• To determine the efficacy of organic versus inorganic selenium sources in sheep.
• To evaluate the effects of supranutritional selenium supplementation on ewe health and lamb growth.

Main Methods:

• 240 mature ewes were assigned to 8 treatment groups receiving different selenium (Se) forms (Na-selenite, Na-selenate, Se-yeast) and dosages weekly.
• Treatments were administered for approximately 2 weeks before breeding and continued for 62.5 weeks, with some groups continuing through a second lambing season.
• Ewe reproductive parameters (lambing rate, births, weaning) and progeny performance (lamb weight at specific ages) were monitored.

Main Results:

• Selenium form or dosage did not affect ewe reproductive performance (lambing, births, weaning rates).
• Ewes receiving the highest Se-yeast dosage (24.5 mg Se/wk) showed improved body condition score (BCS) at year-end.
• Lambs born to ewes supplemented with the highest Se-yeast dosage exhibited significantly greater weight gains at 120 days (Year 1) and 60 days (Year 2) compared to controls or lower Se-yeast dosage groups.

Conclusions:

• Supranutritional supplementation with organic Se-yeast at 24.5 mg Se/wk enhances lamb growth and ewe body condition.
• This level of selenium supplementation does not adversely affect ewe reproductive performance.
• Organic Se-yeast offers a promising strategy for improving sheep health and productivity, particularly in scenarios with multiple lambs per ewe.