EFFECT OF DIETARY CALCIUM-CONCENTRATION DURING GESTATION AND LACTATION IN THE SOW ON MILK-COMPOSITION AND LITTER GROWTH

This study evaluated the effects of diets containing varying amounts o f Ca on milk composition and litter characteristics of sows. Yorkshire sows were fed one of the following diets: low Ca (.38%; n = 5), stand ard Ca (.75%; n = 5), or high Ca (1.12%; n = 4). Diets were fed from d 42 of gestation to d 42 of lactation. Milk was collected on d 7 +/- 1 , 21 +/- 1, and 42 +/- 1 of lactation. Lactose was greater (6.4%, P < .05) in milk from sows fed low Ca than in those fed standard (5.5%) or high (5.8%) Ca, but only on d 7 of lactation. No treatment effect or time x treatment interaction was detected for total protein or casein concentrations. Calcium increased(P < .05) over time irrespective of t reatment. There was an increase (P < .05) in ADG on d 7 in pigs from h igh-fed (.28 kg) and low-fed sows (.20 kg) compared with those from st andard-fed sows (.13 kg). In conclusion, body Ca is so physiologically regulated that minor dietary alterations have little overall effect o n milk composition. Alterations in ADG for pigs, especially from sows fed high Ca, warrant further investigation.