The effect of dietary iodine supplementation in dairy goats on milk production traits and milk iodine content

Abstract

Dairy products offer an important source of iodine for humans, particularly infants and children. An adequate iodine content in the diet of lactating animals must guarantee a suitable milk iodine concentration. In this experiment, the effects of iodine supplementation of dairy goat diets on the iodine concentration, milk yield, and milk composition of goat milk were studied. Thirty crossbred dairy goats of the Sarda population were divided into 3 groups supplemented with 0 (control group), 0.45 (group 1), or 0.90 (group 2) mg of KI/d per goat. The dose of KI (76.5% of iodine) was dissolved in water and orally administered with a syringe every day for 10 wk. Mean milk iodine concentrations were 60.1 +/- 50.5, 78.8 +/- 55.4, and 130.2 +/- 62.0 microg/L (mean +/- SD) in the control group, group 1, and group 2, respectively. The extent of iodine enrichment in milk was approximately 31% in group 1 and 117% in group 2 compared with the control group. Milk yield was not influenced by KI supplementation and averaged 1,229, 1,227, and 1,179 g/d in groups 0, 1, and 2, respectively. Milk urea nitrogen concentration was significantly lower in the KI-supplemented groups (32 and 33 mg/dL in groups 1 and 2, respectively) than in the control group (37 mg/dL). Iodine supplementation of dairy goat diets can increase milk iodine content without adverse effects on milk production traits.

Effect of dietary iodine on thyroid hormones and energy blood metabolites in lactating goats

“…The concentration of BUN varied over time, without a defined trend (Figure 3b). The decrease in BUN in the supplemented groups was accompanied by a decrease in milk urea nitrogen from about 37.0 mg/dl in CON to an average of 32.0 mg/dl in the KI supplemented groups (Nudda et al, 2009). Previous observations (Pattanaik et al, 2001) report a greater retention of absorbed nitrogen in iodine-supplemented goats.…”

“…The temporal pattern of insulin evidenced an increase with sampling period (Figure 3a). This pattern could be related to the natural decrease of milk yield as lactation progresses (Nudda et al, 2009), because insulin is correlated negatively with milk yield (Squires, 2010). Blood urea nitrogen (BUN) was significantly lowered by iodine supplementation.…”

“…Animals were fed a commercial concentrate (0.7 kg/day per goat, as fed) individually administered during the two daily milkings (0800 h and 1600 h) as well as ryegrass hay (on average 1.4 kg/day per goat, as fed) split into two feedings, morning and evening, according to recommendations of the Institut National de la Recherche Agronomique (INRA, 1988). The experimental design and protocol were described in detail in a previous paper (Nudda et al, 2009).…”

“…The iodine supplementation of dairy animals increases the iodine content of milk (Antonangeli et al, 2000;Nudda et al, 2009;Moschini et al, 2010) and -E-mail: anudda@uniss.it can enhance the supply of iodine to suckling animals and humans. Iodine supplementation can also modify the function of the thyroid gland through the secretion of TH (Pattanaik et al, 2001;Randhawa and Randhawa, 2001;Qin et al, 2011).…”

“…Our previous paper reported the effect of long-term iodine supplementation on milk iodine concentration without influencing milk production and composition in dairy goats (Nudda et al, 2009). Some studies with goats fed goitrogenic feeds have dealt with the effects of iodine supplementation on TH (Haque et al, 1996;Pattanaik et al, 2001 and2004) and some blood metabolites (i.e.…”