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Metabolic basis for calculating energy and amino acid requirements in the lactating sow
200 SUB-THEME: LACTATION IN THE SOW
37. Utilization of milk nutrients by the suckling piglet. M. Etienne and J. Noblet, I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Milk production (weigh-suckle-weigh technique) and composition were measured at regular intervals [ days (d) 1,5, 9, 13, 17 and 21 after farrowing ] in sows suckling 8 to I 0 piglets. Milk daily nutrient intakes were calculated for periods 1 (dl to 5 ) , 2 (d5 to 9), 3 ( d 9 t o 13),4 (d13 to 17) and5 (d17 to 21 ) and total lactation (dl to 21 ). Piglets were weighed on the same days and slaughtered at weaning (d22) for chemical analysis and calculation of their nutrient balance from d 1 to 22. Mean daily intakes of milk and milk dry matter, nitrogen, fat and energy from dl to 21 were 718 g, 132 g, 5.43 g, 53.5 g and 3.63 MJ per piglet, respectively. All nutrients increased steadily over the lactation: 2.58, 3.31, 3.85, 4.09 and 4.30 MJ per day for energy during periods 1, 2, 3, 4 and 5, respectively. From dl to 22 (on average per day), each piglet gained 195 g body weight (BW) and deposited 4.78 g of nitrogen, 28.7 g of fat and 1.95 MJ of energy. The amounts of milk nitrogen or energy per kg BW gained averaged 28 g and 18.7 MJ, respectively. This ratio was constant for nitrogen but, for energy, it was lower ( P < 0.01 ) during periods 1 and 2 ( 17.4 MJ ) than subsequently ( 19.4 M J). About 85% of nitrogen and 55% of energy of milk were retained in the body of piglets. Assuming an efficiency of milk metabolizable energy (ME) for energy deposition in the body equivalent to 80%, ME requirement for maintenance during the suckling period is 430 kJ per kg metabolic BW ( B W °75). Daily deposition of nutrients by the piglets (from d 1 to 21 ) was linearly related to their daily BW gain, so that composition of additional daily gain was constant: 141 mg, 197 mg and 12.4 kJ of deposited protein, fat and energy, respectively, for each gram increase of empty daily gain. In suckling piglets, daily empty BW gain was a linear function of protein and fat deposition, each gram deposited being associated with 5.2 and 1.2 g empty BW gain, respectively. It is suggested that the protein: energy ratio in sow's milk is low compared to the nutrient requirement for maximal growth in suckling piglets. 38. Metabolic basis for calculating energy and amino acid requirements in the lactating sow. M. Etienne, J. Noblet and J.Y. Dourmad. I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Energy and amino acid requirements in the lactating sow were determined according to a factorial approach. Litter size (LS) and litter growth rate over total lactation (LGR, g/day) were used to estimate energy (Emilk, kJ/ day = 20.6 X L G R - 376 X LS, R 2= 0.87) or nitrogen (Nmilk, g/ d a y = 0 . 0 2 5 7 x L G R + 0 . 4 2 x L S , R2=0.90) output in milk. For energy, the approach was based on estimates of energy requirements for maintenance [ 460
201 kJ metabolizable energy (ME) per kg°75 ] and the efficiencies of utilization of ME from feed (kt = 72%) and from body reserves (krt= 88%) for milk production. Calculations indicate that ME requirements vary according to sow body weight and, to a large extent, to litterweight gain. On average, they are equivalent to 70 to 85 MJ ME per day, these values being often higher than the spontaneous food intake of the lactating sow. The discrepancy between energy requirements and spontaneous energy intake during lactation has then to be considered for calculation of energy requirement during subsequent pregnancy. For lysine, the requirement was estimated from a multiple linear relationship calculated between sow N balance (Nbal, g/day) and crude lysine intake (Lys, g/day) and Nmilk ( N b a l = - 1 6 . 9 + l . 4 1 ×Lys -0.58×Nmilk, R2=0.90). With a zero Nbal objective, corresponding to about 200 g/day muscle weight loss, i.e. around 6 kg over lactation, lysine requirement amounts to 35 to 40 g/day for medium to high yielding sows (2000 to 2500 g/day litter growth rate). From a practical point of view and owing to appetite variations, a 0.85% lysine level in the diet can be advised. For the other essential amino acids (EAA), similar results were not available. A calculation was then proposed for estimating the EAA requirements from the lysine requirement by partitioning total requirement between maintenance and milk production. On that basis, the requirements for methionine, methionine+cystine, threonine and tryptophane amount to 26, 54, 66 and 18% of that for lysine, respectively. 39. Nutritional composition and energy utilization of sow colostrum by the newborn pig. P. Herpin and J. Lc Dividich, I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Pooled sow colostrum was analyzed for whole nutritional composition, including amino acid and mineral contents, and its energy utilization was evaluated using 15 newborn pigs during the first postnatal day. Piglets were restrained in individual cages in respiration chambers and fed intragastrically sow colostrnm at the rate of 6, 12 or 18 g/kg birth weight/feeding. A total of 24 feedings at 60-rain intervals starting 2 hr after birth was provided. Heat production was measured over the whole experiment by continuous indirect calorimetry. The sum of essential amino acids (g/16 g N) amounted to 54.2, 52.5 and 45.8 in colostrum collected during parturition and 24 hr later, and in milk collected on day 15 of lactation, respectively. Corresponding concentrations of minerals (g%, dry matter) were: Ca, 0.28, 0.47 and 0.76; P, 0.48, 0.58 and O.61; Mg, 0.03, 0.04 and 0.04; K, 0.51, 0.65 and 0.43 and those of trace elements (ppm, dry matter): Cu, 13.7, 11.2 and 9.3; Zn, 59.8, 37.8 and 30.6; Mn, 0.5, 0.5 and 0.3; Fe, 20.0, 16.2 and 15.1; Na, 3576, 2186 and 2231. Energy retained [Y, kcal/kg body weight (BW) ] was related to ME intake (X, kcal/kg BW) by the following equation: Y=0.91 ( + 0.06) X - 63.6 (r=0.97, n = 15). Similarly, N retained (Y, g/kg BW) was related to absorbed N (X, g/kg BW) by the following equation: Y=0.89 (y + 0.02) X 0.012 (r=0.99, n = 15). Data indicated rapid post parturition changes in
37. Utilization of milk nutrients by the suckling piglet. M. Etienne and J. Noblet, I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Milk production (weigh-suckle-weigh technique) and composition were measured at regular intervals [ days (d) 1,5, 9, 13, 17 and 21 after farrowing ] in sows suckling 8 to I 0 piglets. Milk daily nutrient intakes were calculated for periods 1 (dl to 5 ) , 2 (d5 to 9), 3 ( d 9 t o 13),4 (d13 to 17) and5 (d17 to 21 ) and total lactation (dl to 21 ). Piglets were weighed on the same days and slaughtered at weaning (d22) for chemical analysis and calculation of their nutrient balance from d 1 to 22. Mean daily intakes of milk and milk dry matter, nitrogen, fat and energy from dl to 21 were 718 g, 132 g, 5.43 g, 53.5 g and 3.63 MJ per piglet, respectively. All nutrients increased steadily over the lactation: 2.58, 3.31, 3.85, 4.09 and 4.30 MJ per day for energy during periods 1, 2, 3, 4 and 5, respectively. From dl to 22 (on average per day), each piglet gained 195 g body weight (BW) and deposited 4.78 g of nitrogen, 28.7 g of fat and 1.95 MJ of energy. The amounts of milk nitrogen or energy per kg BW gained averaged 28 g and 18.7 MJ, respectively. This ratio was constant for nitrogen but, for energy, it was lower ( P < 0.01 ) during periods 1 and 2 ( 17.4 MJ ) than subsequently ( 19.4 M J). About 85% of nitrogen and 55% of energy of milk were retained in the body of piglets. Assuming an efficiency of milk metabolizable energy (ME) for energy deposition in the body equivalent to 80%, ME requirement for maintenance during the suckling period is 430 kJ per kg metabolic BW ( B W °75). Daily deposition of nutrients by the piglets (from d 1 to 21 ) was linearly related to their daily BW gain, so that composition of additional daily gain was constant: 141 mg, 197 mg and 12.4 kJ of deposited protein, fat and energy, respectively, for each gram increase of empty daily gain. In suckling piglets, daily empty BW gain was a linear function of protein and fat deposition, each gram deposited being associated with 5.2 and 1.2 g empty BW gain, respectively. It is suggested that the protein: energy ratio in sow's milk is low compared to the nutrient requirement for maximal growth in suckling piglets. 38. Metabolic basis for calculating energy and amino acid requirements in the lactating sow. M. Etienne, J. Noblet and J.Y. Dourmad. I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Energy and amino acid requirements in the lactating sow were determined according to a factorial approach. Litter size (LS) and litter growth rate over total lactation (LGR, g/day) were used to estimate energy (Emilk, kJ/ day = 20.6 X L G R - 376 X LS, R 2= 0.87) or nitrogen (Nmilk, g/ d a y = 0 . 0 2 5 7 x L G R + 0 . 4 2 x L S , R2=0.90) output in milk. For energy, the approach was based on estimates of energy requirements for maintenance [ 460
201 kJ metabolizable energy (ME) per kg°75 ] and the efficiencies of utilization of ME from feed (kt = 72%) and from body reserves (krt= 88%) for milk production. Calculations indicate that ME requirements vary according to sow body weight and, to a large extent, to litterweight gain. On average, they are equivalent to 70 to 85 MJ ME per day, these values being often higher than the spontaneous food intake of the lactating sow. The discrepancy between energy requirements and spontaneous energy intake during lactation has then to be considered for calculation of energy requirement during subsequent pregnancy. For lysine, the requirement was estimated from a multiple linear relationship calculated between sow N balance (Nbal, g/day) and crude lysine intake (Lys, g/day) and Nmilk ( N b a l = - 1 6 . 9 + l . 4 1 ×Lys -0.58×Nmilk, R2=0.90). With a zero Nbal objective, corresponding to about 200 g/day muscle weight loss, i.e. around 6 kg over lactation, lysine requirement amounts to 35 to 40 g/day for medium to high yielding sows (2000 to 2500 g/day litter growth rate). From a practical point of view and owing to appetite variations, a 0.85% lysine level in the diet can be advised. For the other essential amino acids (EAA), similar results were not available. A calculation was then proposed for estimating the EAA requirements from the lysine requirement by partitioning total requirement between maintenance and milk production. On that basis, the requirements for methionine, methionine+cystine, threonine and tryptophane amount to 26, 54, 66 and 18% of that for lysine, respectively. 39. Nutritional composition and energy utilization of sow colostrum by the newborn pig. P. Herpin and J. Lc Dividich, I.N.R.A., Station de Recherches Porcines, 35590 Saint Gilles, France. Pooled sow colostrum was analyzed for whole nutritional composition, including amino acid and mineral contents, and its energy utilization was evaluated using 15 newborn pigs during the first postnatal day. Piglets were restrained in individual cages in respiration chambers and fed intragastrically sow colostrnm at the rate of 6, 12 or 18 g/kg birth weight/feeding. A total of 24 feedings at 60-rain intervals starting 2 hr after birth was provided. Heat production was measured over the whole experiment by continuous indirect calorimetry. The sum of essential amino acids (g/16 g N) amounted to 54.2, 52.5 and 45.8 in colostrum collected during parturition and 24 hr later, and in milk collected on day 15 of lactation, respectively. Corresponding concentrations of minerals (g%, dry matter) were: Ca, 0.28, 0.47 and 0.76; P, 0.48, 0.58 and O.61; Mg, 0.03, 0.04 and 0.04; K, 0.51, 0.65 and 0.43 and those of trace elements (ppm, dry matter): Cu, 13.7, 11.2 and 9.3; Zn, 59.8, 37.8 and 30.6; Mn, 0.5, 0.5 and 0.3; Fe, 20.0, 16.2 and 15.1; Na, 3576, 2186 and 2231. Energy retained [Y, kcal/kg body weight (BW) ] was related to ME intake (X, kcal/kg BW) by the following equation: Y=0.91 ( + 0.06) X - 63.6 (r=0.97, n = 15). Similarly, N retained (Y, g/kg BW) was related to absorbed N (X, g/kg BW) by the following equation: Y=0.89 (y + 0.02) X 0.012 (r=0.99, n = 15). Data indicated rapid post parturition changes in