|
|
||||||||
,3


* West Central Research & Outreach Center, University of Minnesota, Morris 56267;
and
Department of Animal Science, University of Minnesota, St. Paul 55108; and
and
Southern Research & Outreach Center, University of Minnesota, Waseca 56093
| Abstract |
|---|
|
|
|---|
Key Words: Lactation Meat Byproducts Milk Chocolate Sows Sucrose
| Introduction |
|---|
|
|
|---|
Flavoring agents can improve the voluntary feed intake of nursery pigs and may improve diet acceptability for lactating sows (Orr and Tribble, 1977
). Young pigs consume more of a diet containing elevated levels of sucrose (5%) compared with pigs fed diets based on corn, soybean meal, and dried whey when offered a choice of diets (Wahlstrom et al., 1974
). Yang et al. (1997)
reported that nursery pigs expressed a clear preference for diets that contained milk chocolate product (MCP), a by-product of food manufacture for humans.
Dietary dried porcine solubles (DPS), the residues remaining after extraction of heparin from porcine intestines, improved the growth performance of weaned pigs (Zimmerman et al., 1997
; Lindemann et al., 1998
). Experiences under commercial conditions suggest that the feed intake of lactating sows may be enhanced by the inclusion of DPS in diets. No studies under controlled conditions have been conducted to document these observations.
Our objectives were to determine the voluntary feed intake and performance of lactating sows fed diets containing a sucrose/milk chocolate product blend (Exp. 1) or dried porcine solubles (Exp. 2).
| Materials and Methods |
|---|
|
|
|---|
Litter management practices reflected those commonly employed in the commercial swine industry. Within 3 d after farrowing, all litters were adjusted, irrespective of dietary treatment, to a minimum of nine pigs. Every effort was made to maintain at least nine pigs per litter during the experiments. If a pig died during lactation, a pig of similar weight from a litter not involved in the experiment was used to replace the dead pig within 18 h. Pigs had their ears notched, tails docked, and needle teeth clipped within 24 h of birth. An injection of iron was administered by d 3 after farrowing. Creep feed was not offered to litters, but pigs had access to sow feed.
On the day of weaning, sows were separated from their litters and moved to a confinement breeding facility. Sows were checked daily for signs of estrus using a mature boar. Estrus was recorded when sows stood to be mounted by a boar; days from weaning to estrus were recorded. Sows were removed from the experiment when they displayed estrus or on d 15 postweaning, whichever occurred earlier. If a sow was anestrous through d 15 postweaning, a weaning-to-estrus interval was not recorded for that sow. These sows had missing data for weaning-to-estrus interval in their record.
Experiment 1.
One hundred eight sows (54 sows from each research center) were assigned, based on parity and expected farrowing date, to one of two experimental diets (Table 1
), which were formulated to contain 0.9% total lysine. The sucrose/MCP blend consisted of two-thirds sucrose and one-third MCP. This blend when included in the diet at 6% at the expense of corn provided 4% sucrose and 2% MCP to the final diet.
|
Experiment 2.
One hundred nineteen sows (n = 66 and 53 for the West Central and Southern Research Centers, respectively) were assigned to three dietary treatments during lactation. Corn-soybean mealbased diets were formulated to contain 0.9% total lysine and 0, 1.5, or 3.0% DPS (Table 2
). Dried porcine solubles were included in the appropriate diets using DPS-30 (Nutra-Flo Protein Products, Sioux City, IA). Sows were assigned to dietary treatments based on parity and expected farrowing date within each station.
|
Statistical Analyses.
Data were analyzed by least squares analysis of covariance (Gill, 1978
) using the GLM procedure of SAS (SAS Inst. Inc., Cary, NC). In Exp. 1, parity was used initially as a class variable and included in the statistical model. However, the very small number of advanced-parity sows at the Southern Research Center caused extreme adjustments in the least squares means for many response variables, which was considered misleading. Consequently, linear and quadratic parity terms were included as covariates in the analysis of all response variables for the final statistical analysis. Lactation length was the covariate for sow feed intake, backfat depth of sows, litter weight at weaning, and postweaning interval to estrus. Prefarrowing sow weight was the covariate for subsequent sow weights. Litter weight after cross-fostering was used as a covariate for subsequent litter weights and daily litter weight gain data. In Exp. 2, parity was used as a covariate for analysis of all response variables. Number of pigs per litter after cross-fostering and lactation length were used (in addition to parity) as covariates for subsequent litter size and litter weight data. Parity and lactation length were used as covariates for analysis of dietary influences on sow feed intake and postweaning interval to estrus.
In both experiments, parity accounted for a significant portion (P < 0.05) of the variation in response variables. In most instances, the covariates other than parity also accounted for a significant portion (P < 0.05) of the variation in response variables. The statistical model used for analysis of both experiments included the main effects of station, dietary treatment, the nested effect of farrowing group within station, all possible two-way interactions among main and nested effects, and the appropriate covariates mentioned above. Where appropriate, linear contrasts were used to separate means. Chi-square analysis was used to evaluate the effects of dietary treatment on the occurrence of behavioral estrus by d 15 postweaning. Data are reported as least squares means.
| Results and Discussion |
|---|
|
|
|---|
Inclusion of a sucrose/MCP blend in a standard corn-soybean meal diet had no significant influence on average feed intake of lactating sows (Table 3
). Research center and diet interacted (P < 0.05) to influence weight changes of sows during lactation. Sows at the Southern Research Center lost body weight during lactation regardless of the diet to which they were assigned, whereas sows at the West Central Research Center lost weight when fed the control diet and gained weight when fed the diet containing sucrose/MCP. Neither backfat depth of sows nor change in backfat depth was influenced by dietary treatment.
|
Over the entire experiment regardless of station, 63% of sows fed the control diet expressed estrus by d 15 postweaning whereas 76% of sows fed the sucrose/MCP blend expressed estrus. These differences were not significant (
2 = 2.14; P < 0.15). The poor rebreeding performance of sows at the Southern compared with the West Central Research Center may be explained partially by age of the sows. Mean parity of sows at the Southern Research Center was 1.8 vs. 3.8 for sows at the West Central Research Center (Table 3
). Other researchers (Rasbech, 1969
; Newton and Mahan, 1993
; Yang et al., 2000
) demonstrated improved postweaning reproductive performance with increasing parity of the sow. In the article by NCR-89 (1990)
, it was reported that inclusion of 2.5% sucrose in the diet of lactating sows decreased the proportion of sows displaying estrus by d 30 postweaning; however, their finding was not significant and they did not report parity information for the sows studied.
Dietary treatment had no significant effect on litter size at any time during lactation (Table 4
). A research center x dietary treatment interaction (P < 0.05) was observed for total litter weight at birth and after cross-fostering. This significant interaction continued throughout lactation. By the end of lactation, a 2% improvement in litter weight and daily litter weight gain was noted for sows fed the sucrose/MCP blend at the Southern Research Center. In contrast, sows fed the sucrose/MCP blend at the West Central Research Center weaned litters that were 6% lighter and gained 7% slower than contemporary litters nursing sows fed the control diet. Using litter weight as a gross indicator of the sows milk production, one could infer a subtle decline in milk production of sows at the West Central Research Center when the diet contained the sucrose/MCP blend at a level of 6%. The slight reduction in litter weight gain combined with the small gains in sow weight during lactation when the sucrose/MCP blend was included in the diet suggests these sows may have redirected absorbed nutrients away from milk production in favor of maternal body tissue. In some situations, this redirection of nutrients may be favorable to subsequent reproductive performance of sows; however, we observed no significant effects of diet on either the postweaning interval to estrus or the proportion of sows displaying estrus at the West Central Research Center.
|
Experiment 2.
Effects of research center and farrowing group were significant for many response variables; however, these effects are not reported or discussed because they are not the focus of this experiment. There were no significant interactions between dietary treatments and research center or dietary treatments and farrowing group, suggesting that the effects of diet were consistent at both research centers and across farrowing groups. The remainder of this discussion will focus on the main effects of dietary treatment on sow performance.
The most important finding in this investigation was the effects of DPS on voluntary feed intake of sows. Dried porcine solubles tended to increase the total amount of feed consumed by sows (P < 0.10) through d 9 of lactation and through weaning (Table 5
). This observation resulted in a tendency for sows fed increasing dietary concentrations of DPS to exhibit a linear increase (P < 0.10) in average daily feed intake over the entire lactation. Lindemann et al. (1998)
reported a similar improvement in voluntary feed intake of nursery pigs fed up to 6% DPS. Koehler et al. (1998)
observed marginal improvements in daily feed intake and gain of nursery pigs fed 2.5% DPS, which were enhanced by the addition of 4% spray-dried porcine plasma. Others (Bregendahl et al., 1998
; DeRouchey et al., 2000
) found no effect of dietary DPS on feed intake of nursery pigs, but Zimmerman et al. (1997)
consistently observed increased feed intake of nursery pigs previously fed DPS. The greatest numerical increase in the feed intake of sows in the present study resulted from 1.5% dietary DPS. As DPS addition increased to 3.0%, voluntary feed intake declined but still exceeded that of sows offered the control diet.
|
Similar to sow body weight and backfat depth, dietary DPS did not have any significant effects on litter size or litter weight throughout lactation (Table 6
). Litter size after cross-fostering was different across dietary treatments. This result represents a chance occurrence that we do not attribute to a biological effect of DPS. Consequently, we used litter size after transfer (in addition to parity) as a covariate for analysis of all subsequent litter size and weight data. Since dietary treatments were not imposed until after farrowing, we did not expect any effects of DPS on initial litter size. Apparently, DPS had no effect on milk production of sows because we observed no differences in litter weight at any time during lactation. Daily litter weight gain was 2.15, 2.10, and 2.00 kg for sows assigned to 0, 1.5, and 3.0% DPS diets, respectively.
|
| Implications |
|---|
|
|
|---|
The inclusion of 4% sucrose and 2% milk chocolate product in corn-soybean mealbased lactation diets did not seem to enhance voluntary feed intake of lactating sows, nor did it improve growth performance of nursing piglets. Dried porcine solubles included in corn-soybean meal diets at 1.5% tended to increase the feed intake of lactating sows.
| Footnotes |
|---|
3 Present address: Dept. of Animal Sciences, University of Illinois, Urbana. ![]()
2 Correspondence: 46352 State Highway 329 (phone: 320-589-1711; fax: 320-589-4870; E-mail: johnstlj{at}mrs.umn.edu).
Received for publication March 28, 2003. Accepted for publication June 18, 2003.
| Literature Cited |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
R. L. Payne, R. D. Lirette, T. D. Bidner, and L. L. Southern Effects of a novel carbohydrate and protein source on sow performance during lactation J Anim Sci, August 1, 2004; 82(8): 2392 - 2396. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |