As a guideline, heifers should have attained 80 percent of their mature body weight at calving. The nutritional program during the dry period has an impact on cows' reproduction. During periods of nutrient insufficiencies, the fetus and reproductive tissue will have first priority for nutrients and the dam will mobilize nutrients from her body to meet the fetus' nutrient requirements. However, if the dam's reserves are unable to supply adequate nutrients, normal fetal development subsides and death, malformations or reduced viability of the offspring result. In acute, severe malnutrition, abortion or premature delivery does not act as a protective mechanism for the dam, instead it precedes the death of the dam.
Nutrients can affect fetal development.
Table 3 lists some nutrient deficiencies and resulting clinical signs in offspring. Influence of dry cow nutrient deficiencies on calf viability. Deficiency symptoms and associated Nutrient problems in calves Energy Small calf weight at birth, unthrifty, slow growing calves. Phosphorus Seldom a problem, bone loss from dam provides sufficient calcium and phospho- rus for fetal development. Iodine Big neck on goiter in newborn calves.