The effect of source of supplemental dietary energy on sow milk yield, milk composition and litter performance.

Abstract

Ten crossbred sows were used per treatment to determine production and composition of milk and litter growth. Treatment 1 consisted of a basal diet plus animal fat from d 109 of gestation until farrowing, then only the basal diet through lactation. Treatment 2 was the same level of basal diet plus animal fat from d 109 of gestation to d 21 of lactation. Treatment 3 was the basal diet plus cornstarch in amounts to provide the same energy levels as treatment 2. All treatments were isonitrogenous. Milk yield at d 14 of lactation was increased (P<.05) approximately 30% by the addition of lipids to sow diets. Average pig and litter weights were not different among treatments at birth or on d 7, 14 and 21 of lactation. Feeding fat to sows throughout lactation increased (P<.05) the percentage of total lipids in milk. There were no treatment differences in milk crude protein, lactose, total solids and solids-nonfat percentages and pH. Vitamin A content of milk was increased (P<.05) by lipid feeding during lactation. There were significant treatment × day of lactation interactions for palmitic and palmitoleic acid content, resulting in an overall lower level (P<.05) of these fatty acids in milk from sows fed lipids during lactation. Percentages of stearic, oleic, linoleic and linolenic acids did not differ between treatments, but milk from sows fed treatment 2 did tend to have elevated amounts of 18 carbon-length fatty acids in milk as lactation progressed. Data were summarized by day of lactation to examine changes in milk composition during lactation. Total lipids increased (P<.05) from farrowing to d 3 of lactation, and then tended to decline to weaning. Crude protein was higher (P<.05) in colostrum than in milk. Lactose tended to increase from colostrum to milk, while total solids and solids-nonfat tended to decrease. Vitamin A was highest (P<.05) in colostrum. In general, 16 carbon-length fatty acids increased (P<.05) as lactation continued, while 18 carbon-length fatty acids decreased (P<.05). The concentrations of 16 minerals were determined in milk. The Ca to P ratio increased from less than 1.0 at farrowing to approximately 1.5 at weaning. The K and Na concentrations decreased (P<.05) with each sampling period. Zinc decreased (P<.05) during the first week of lactation while Co did not change between d 1 and 7, but decreased (P<.05) by d 21 of lactation.