AND LACTATION B. G. Harmon, C. T. Liu, A. H. Jensen and D. H. Baker Illinois Agricultural Experiment Station, Urbana 61801
Summary One hundred and twelve gilts were bred and assigned to gestation treatments in which they were fed a corn-soybean meal diet (.33% P) with no supplemental phosphorus or sufficient dicalcium phosphate to give a total of .68% dietary phosphorus. At parturition the sows within each gestation treatment were rendomly assigned to dietary treatments of a cornsoybean meal diet fortified to contain .45, .55 or .65% phosphorus for a 28-day lactation. Low dietary phosphorus did not significantly reduce litter size at birth or weaning, weight gain to weaning, sow weight gain during gestation or lactation, milk production or composition, or sow bone calcium or phosphorus. Lactating sows fed .45% phosphorus digested and retained less phosphorus than did sows on the other two treatments. Although bone ash values were high for all sows after lactation, the sows fed .45% phosphorus had significantly lower values. With sows on tests through one litter the unsupplemented diet (.33% P) was adequate during gestation and .45% phosphorus proved to be adequate during lactation. The reduced bone ash observed in sows fed the lowest level of phosphorus suggests that sows retained for multiple parities may require increased phosphorus for greater bone strength.
Introduction
ment during gestation and lactation at .50%. Insufficient research with sows has been conducted in the intervening period to substantiate either level of phosphorus as a dietary requirement. Kornegay et al. (1973) studied reproductive performance in multipleparity sows fed either high calcium and phosphorus or low calcium and phosphorus. There were no significant differences between dietary treatments for any reproductive or tissue parameter. Dudley (1960) and Harmon et aL (1974) evaluated different phosphorus sources for sows with diets fortified to contain .5% phosphorus. Each study included unsupplemented cornsoybean meal diets. In studies conducted on pasture and in dry lot (Dudley, 1960) sows fed unsupplemented corn-soybean meal diets containing .31% phosphorus through two parities had no criteria statistically different from the sows fed diets containing .5% phosphorus. Harmon et al. (1974) observed a high incidence of posterior paralysis in sows fed the unsupplemented diet when sows lactated for 8 weeks. The condition was not observed when lactation was terminated after 4 weeks. The present study was conducted to more clearly define the phosphorus requirement of firstlitter sows during gestation and lactation.
Experimental Procedure
A total of 112 Hampshire, Yorkshire and The phosphorus requirement during gestation and lactation is based on limited research crossbred gilts were farrowed over a period of 1 data. Mitchell et al. (1931) measured the year. As bred the grits were formed into phosphorus deposition in the products of outcome groups and randomly assigned to two conception at weekly intervals while feeding a dietary treatments. They were housed in an diet that contained .36% phosphorus. The environmentally modified building in individual N.R.C. (1973) estimates the phosphorus require- pens measuring one-half by two meters. 660 JO U R N A L OF-ANIMAL SCIENCE, vol. 40, no. 4, 19"/5
Downloaded from https://academic.oup.com/jas/article-abstract/40/4/660/4668001 by Iowa State University user on 25 January 2019
PHOSPHORUS REQUIREMENTS OF SOWS DURING G E S T A T I O N
HARMON ET AL.
Results and Discussion
Gestation gain, litter size and litter weight were similar for firstqitter sows fed either a
corn-soybean meal diet with no supplemental phosphorus (.33%) or with supplemental phosphorus (.68% total phosphorus, table 2). Weight gain of the litter from birth to weaning was not affected (P < .05) by dietary treatment during gestation. The results are similar to those reported previously (Harmon et al., 1974) for sows receiving .31 or .51% phosphorus. Number of pigs weaned was not influenced by phosphorus level fed during lactation; however, sows fed the highest level of phosphorus during lactation weaned lighter pigs ( P < .05) than sows fed the lower levels of phosphorus (table 3). Litter size at birth was not significantly affected by the breeding groups, but litter weight gain to weaning was significantly less ( P < .01) for the Hampshire pigs than for the Yorkshire or crossbred pigs. The weight loss by sows during the 28-day lactation averaged 17 kg and was not influenced (P < .05) by gestation and lactation treatments or breeding group. Milk production is shown in tables 2 and 3 and composition is shown in table 3. Daily milk yield, determined at two times (1 lth and 25th days) during lactation, was not ( P < .05) influenced by the level of phosphorus fed during lactation. However, the sows that received supplemental phosphorus during gestation produced more milk ( P < .01) in late lactation. The breed effect on milk production was significant ( P < .01) as the Hampshires produced less milk than the other breeding groups. When daily milk production was expressed on a per pig basis, the values for the Hampshire breed were lower (P < .05) only for the collection made on the I I th day. The concentration of calcium and phosphorus in the milk was not influenced by
TABLE 1. COMPOSITION OF EXPERIMENTAL DIETS
Gestation
Phase
Phosphorus, %
Ref. No.
.33
Corn Soybean meal (49%) Dicalcium phosphate Limestone
4-02-931 5-04-612 6-01-080 6-02-632
79.7 18.0
79.1 18.0
--
1.7
Trace mineral salt a Vitamin mixture a
1.7 95 .1
Chromic oxide
--
aHarmon
e t al.
(1970).
.68
.6 .5 .1 --
Lactation .45 79.5 18.0 .5
.55
.65
79.3 18.0
79.1 18.0
1.0
1.5
1.3 .5 .1
1.0 .5 .1
.7 .5 .1
.1
.1
.1
Downloaded from https://academic.oup.com/jas/article-abstract/40/4/660/4668001 by Iowa State University user on 25 January 2019
Previous to the experiment the gilts had been grown receiving diets containing .7% calcium and .5% phosphorus. During gestation they were fed daily 1.8 kg of diet containing either .33% or .68% phosphorus (table 1). All diets contained .70% calcium and 330,000 IU vitamin D per kilogram of diet. Throughout lactation, sows were fed 1 kg thrice daily of diets containing .45, .55 or .65% phosphorus. The feeding levels were established to limit intake during gestation and approach ad libitum consumption during lactation. No creep diet was available although it was possible for pigs to obtain some feed from the sow feeder. Calcium and phosphorus balance of the sows was measured in 5-day collection periods during the eighth to 13th and 23rd to 28th days of lactation. Milk production was measured on the l l t h and 25th days of lactation. The composition of milk was determined on samples collected 1 day after milk production was measured. The procedures used for the balance trials with nursing sows, measuring milk production and sampling milk have been described previously (Harmon et al., 1974). Pigs were weaned at 28 days of age and within 72 hr the sows were killed and turbinates and 10th ribs were removed for analysis. Calcium and phosphorus analyses were made on diet, feces, urine, milk and bones (Harmon et al., 1970; Harmon etal., 1974). An analysis of variance of the factorially arranged treatments was calculated for each criterion.
661
HARMON ET AL.
662
TABLE 2. EFFECTS OF PHOSPHORUS LEVELS DURING GESTATION ON REPRODUCTIVE PERFORMANCE Breed a Diet phosphorus, %
Yorkshire
Crossbred
.33
.68
.33
.68
.33
.68
48.1 8.4 7.6 11.4 10.4 6.2 29.1
50.6 7.9 7.3 14.0 10.0 5.9 22.0
49.9 9.4 7.9 10.3 9.3 7.3 29.9
55.4 10.5 9.8 11.9 11.1 8.8 33.1
54.4 8.9 8.6 12.2 11.9 7.8 33.2
50.6 9.2 7.8 13.0 11.4 7.4 31.2
2.0 1.9
2.1 2.2
3.0 2.4
3.1 3.4
3.5 3.1
3.0 3.0
303 305
342 371
418 315
369 341
405 397
450 498
aTotal of 1 1 2 s o w s ; 4 6 Hampshires, 4 7 York,shires and 19 crossbreds. bSignificantly (P ~ .01) l o w e r for Hampshire s o w s . CSignificantly (P < .05) l o w e r for Hampshire SOws.
the lowest level of phosphorus supplementation (.09% P). Digestibility increased (P < .01) as the lactation dietary phosphorus increased. Phosphorus retention values also increased significantly ( P < .01), but the magnitude of differences between treatment means was much less. This indicates that urinary phosphorus increased as dietary phosphorus increased. Such an increase would be expected if the dietary needs had been exceeded. Phosphorus and
dietary treatment. Calcium and phosphorus concentrations were higher ( P < .01) on the 25th than on the 1 l t h day of lactation. Five-day balance trials (table 4), started 8 and 23 days after parturition, demonstrate once again that phosphorus in corn and soybean meal is poorly utilized (Harmon et al., 1970; Bayley and Thomson, 1969; Harmon et al., 1974). Phosphorus digestibility was less than 37% during each collection period for sows receiving
TABLE 3. EFFECT OF PHOSPHORUS LEVELS DURING GESTATION AND LACTATION ON REPRODUCTIVE PERFORMANCE Diet phosphorus, % Gestation Lactation No. pigs weaneda Litter wt gain, 28 days, kgb
Sow lactation, gain, kg Milk prod/day, kg llth 25th c Ca rag/100 ml milkd 11th day 25th day P rag/100 ml milkd 11th day 25th day
.33 .55
.45
.65
.68 .55
.45
.65
7.5 31.3
7.5 33.6
6.7 29.7
7.4 29.3
7.2 31.9
7.1 23.4
-- 19.7
-- 13.3
-- 17.0
- - 21.0
-- 17.1
-- 18.3
2.8 2.1
3.0 2.7
2.5 2.5
2.6 2.7
2.9 3.2
2.8 2.7
198 248
189 242
174 219
193 245
188 218
211 237
141 165
136 167
135 155
128 165
137 151
135 160
aTotal of 112 litters. bSignificantly lower (P
Summary One hundred and twelve gilts were bred and assigned to gestation treatments in which they were fed a corn-soybean meal diet (.33% P) with no supplemental phosphorus or sufficient dicalcium phosphate to give a total of .68% dietary phosphorus. At parturition the sows within each gestation treatment were rendomly assigned to dietary treatments of a cornsoybean meal diet fortified to contain .45, .55 or .65% phosphorus for a 28-day lactation. Low dietary phosphorus did not significantly reduce litter size at birth or weaning, weight gain to weaning, sow weight gain during gestation or lactation, milk production or composition, or sow bone calcium or phosphorus. Lactating sows fed .45% phosphorus digested and retained less phosphorus than did sows on the other two treatments. Although bone ash values were high for all sows after lactation, the sows fed .45% phosphorus had significantly lower values. With sows on tests through one litter the unsupplemented diet (.33% P) was adequate during gestation and .45% phosphorus proved to be adequate during lactation. The reduced bone ash observed in sows fed the lowest level of phosphorus suggests that sows retained for multiple parities may require increased phosphorus for greater bone strength.
Introduction
ment during gestation and lactation at .50%. Insufficient research with sows has been conducted in the intervening period to substantiate either level of phosphorus as a dietary requirement. Kornegay et al. (1973) studied reproductive performance in multipleparity sows fed either high calcium and phosphorus or low calcium and phosphorus. There were no significant differences between dietary treatments for any reproductive or tissue parameter. Dudley (1960) and Harmon et aL (1974) evaluated different phosphorus sources for sows with diets fortified to contain .5% phosphorus. Each study included unsupplemented cornsoybean meal diets. In studies conducted on pasture and in dry lot (Dudley, 1960) sows fed unsupplemented corn-soybean meal diets containing .31% phosphorus through two parities had no criteria statistically different from the sows fed diets containing .5% phosphorus. Harmon et al. (1974) observed a high incidence of posterior paralysis in sows fed the unsupplemented diet when sows lactated for 8 weeks. The condition was not observed when lactation was terminated after 4 weeks. The present study was conducted to more clearly define the phosphorus requirement of firstlitter sows during gestation and lactation.
Experimental Procedure
A total of 112 Hampshire, Yorkshire and The phosphorus requirement during gestation and lactation is based on limited research crossbred gilts were farrowed over a period of 1 data. Mitchell et al. (1931) measured the year. As bred the grits were formed into phosphorus deposition in the products of outcome groups and randomly assigned to two conception at weekly intervals while feeding a dietary treatments. They were housed in an diet that contained .36% phosphorus. The environmentally modified building in individual N.R.C. (1973) estimates the phosphorus require- pens measuring one-half by two meters. 660 JO U R N A L OF-ANIMAL SCIENCE, vol. 40, no. 4, 19"/5
Downloaded from https://academic.oup.com/jas/article-abstract/40/4/660/4668001 by Iowa State University user on 25 January 2019
PHOSPHORUS REQUIREMENTS OF SOWS DURING G E S T A T I O N
HARMON ET AL.
Results and Discussion
Gestation gain, litter size and litter weight were similar for firstqitter sows fed either a
corn-soybean meal diet with no supplemental phosphorus (.33%) or with supplemental phosphorus (.68% total phosphorus, table 2). Weight gain of the litter from birth to weaning was not affected (P < .05) by dietary treatment during gestation. The results are similar to those reported previously (Harmon et al., 1974) for sows receiving .31 or .51% phosphorus. Number of pigs weaned was not influenced by phosphorus level fed during lactation; however, sows fed the highest level of phosphorus during lactation weaned lighter pigs ( P < .05) than sows fed the lower levels of phosphorus (table 3). Litter size at birth was not significantly affected by the breeding groups, but litter weight gain to weaning was significantly less ( P < .01) for the Hampshire pigs than for the Yorkshire or crossbred pigs. The weight loss by sows during the 28-day lactation averaged 17 kg and was not influenced (P < .05) by gestation and lactation treatments or breeding group. Milk production is shown in tables 2 and 3 and composition is shown in table 3. Daily milk yield, determined at two times (1 lth and 25th days) during lactation, was not ( P < .05) influenced by the level of phosphorus fed during lactation. However, the sows that received supplemental phosphorus during gestation produced more milk ( P < .01) in late lactation. The breed effect on milk production was significant ( P < .01) as the Hampshires produced less milk than the other breeding groups. When daily milk production was expressed on a per pig basis, the values for the Hampshire breed were lower (P < .05) only for the collection made on the I I th day. The concentration of calcium and phosphorus in the milk was not influenced by
TABLE 1. COMPOSITION OF EXPERIMENTAL DIETS
Gestation
Phase
Phosphorus, %
Ref. No.
.33
Corn Soybean meal (49%) Dicalcium phosphate Limestone
4-02-931 5-04-612 6-01-080 6-02-632
79.7 18.0
79.1 18.0
--
1.7
Trace mineral salt a Vitamin mixture a
1.7 95 .1
Chromic oxide
--
aHarmon
e t al.
(1970).
.68
.6 .5 .1 --
Lactation .45 79.5 18.0 .5
.55
.65
79.3 18.0
79.1 18.0
1.0
1.5
1.3 .5 .1
1.0 .5 .1
.7 .5 .1
.1
.1
.1
Downloaded from https://academic.oup.com/jas/article-abstract/40/4/660/4668001 by Iowa State University user on 25 January 2019
Previous to the experiment the gilts had been grown receiving diets containing .7% calcium and .5% phosphorus. During gestation they were fed daily 1.8 kg of diet containing either .33% or .68% phosphorus (table 1). All diets contained .70% calcium and 330,000 IU vitamin D per kilogram of diet. Throughout lactation, sows were fed 1 kg thrice daily of diets containing .45, .55 or .65% phosphorus. The feeding levels were established to limit intake during gestation and approach ad libitum consumption during lactation. No creep diet was available although it was possible for pigs to obtain some feed from the sow feeder. Calcium and phosphorus balance of the sows was measured in 5-day collection periods during the eighth to 13th and 23rd to 28th days of lactation. Milk production was measured on the l l t h and 25th days of lactation. The composition of milk was determined on samples collected 1 day after milk production was measured. The procedures used for the balance trials with nursing sows, measuring milk production and sampling milk have been described previously (Harmon et al., 1974). Pigs were weaned at 28 days of age and within 72 hr the sows were killed and turbinates and 10th ribs were removed for analysis. Calcium and phosphorus analyses were made on diet, feces, urine, milk and bones (Harmon et al., 1970; Harmon etal., 1974). An analysis of variance of the factorially arranged treatments was calculated for each criterion.
661
HARMON ET AL.
662
TABLE 2. EFFECTS OF PHOSPHORUS LEVELS DURING GESTATION ON REPRODUCTIVE PERFORMANCE Breed a Diet phosphorus, %
Yorkshire
Crossbred
.33
.68
.33
.68
.33
.68
48.1 8.4 7.6 11.4 10.4 6.2 29.1
50.6 7.9 7.3 14.0 10.0 5.9 22.0
49.9 9.4 7.9 10.3 9.3 7.3 29.9
55.4 10.5 9.8 11.9 11.1 8.8 33.1
54.4 8.9 8.6 12.2 11.9 7.8 33.2
50.6 9.2 7.8 13.0 11.4 7.4 31.2
2.0 1.9
2.1 2.2
3.0 2.4
3.1 3.4
3.5 3.1
3.0 3.0
303 305
342 371
418 315
369 341
405 397
450 498
aTotal of 1 1 2 s o w s ; 4 6 Hampshires, 4 7 York,shires and 19 crossbreds. bSignificantly (P ~ .01) l o w e r for Hampshire s o w s . CSignificantly (P < .05) l o w e r for Hampshire SOws.
the lowest level of phosphorus supplementation (.09% P). Digestibility increased (P < .01) as the lactation dietary phosphorus increased. Phosphorus retention values also increased significantly ( P < .01), but the magnitude of differences between treatment means was much less. This indicates that urinary phosphorus increased as dietary phosphorus increased. Such an increase would be expected if the dietary needs had been exceeded. Phosphorus and
dietary treatment. Calcium and phosphorus concentrations were higher ( P < .01) on the 25th than on the 1 l t h day of lactation. Five-day balance trials (table 4), started 8 and 23 days after parturition, demonstrate once again that phosphorus in corn and soybean meal is poorly utilized (Harmon et al., 1970; Bayley and Thomson, 1969; Harmon et al., 1974). Phosphorus digestibility was less than 37% during each collection period for sows receiving
TABLE 3. EFFECT OF PHOSPHORUS LEVELS DURING GESTATION AND LACTATION ON REPRODUCTIVE PERFORMANCE Diet phosphorus, % Gestation Lactation No. pigs weaneda Litter wt gain, 28 days, kgb
Sow lactation, gain, kg Milk prod/day, kg llth 25th c Ca rag/100 ml milkd 11th day 25th day P rag/100 ml milkd 11th day 25th day
.33 .55
.45
.65
.68 .55
.45
.65
7.5 31.3
7.5 33.6
6.7 29.7
7.4 29.3
7.2 31.9
7.1 23.4
-- 19.7
-- 13.3
-- 17.0
- - 21.0
-- 17.1
-- 18.3
2.8 2.1
3.0 2.7
2.5 2.5
2.6 2.7
2.9 3.2
2.8 2.7
198 248
189 242
174 219
193 245
188 218
211 237
141 165
136 167
135 155
128 165
137 151
135 160
aTotal of 112 litters. bSignificantly lower (P
