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ANIMAL PRODUCTION |
Department of Animal Science, Michigan State University, East Lansing 48824
| Abstract |
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Key Words: feed intake lactation sow water intake
| INTRODUCTION |
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Agriculture engineers are challenged to design facilities and equipment suitable for animal production, profitability, and environmental compliance, especially those associated with intensive animal feeding operations. The concept of providing lactating sows with eating and drinking choices, with freedom to make decisions relative to when they want to eat, how much they want to eat, and whether they mix feed and water while eating deserves further study.
The objective of this study was to determine the performance of lactating sows, including feed and water intakes, when fed and watered using a self-fed wet/dry (SFWD) feeding system compared with using a conventional hand-fed (HF) dry feeding system.
| MATERIALS AND METHODS |
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Animals and Diets
A total of 114 multiparous Yorkshire (n = 28) or Yorkshire x Landrace (n = 86) sows were randomly assigned based on parity and breed to 1 of 2 treatments during January and February 2002, and from September 2003 to January 2004. The study consisted of 7 replications that farrowed and lactated during the fall and winter seasons. Sow parity ranged from 1 to 9. Sows were moved into farrowing rooms and individual crates 7 d or less before parturition and were fed a corn-soybean meal-based lactation diet from that time until weaning. All sows were treated similarly after weaning; they were moved into individual crates in a breeding room and were managed to stimulate estrus and to be serviced for another pregnancy. A corn-soybean meal-based gestation diet was fed from weaning to estrus. Both diets were in mash form and met or exceeded NRC (1998)
recommendations (Table 1
).
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Two adjacent farrowing rooms were used. The SFWD system was installed in all 12 crates of 1 room, and the HF system was installed in all 12 crates of the other room. Within a room, crates were set on a TriBar slatted floor (Nooyen Inc., Chicago, IL) in a single row and numbered 1 through 12. The rooms were structured and equipped similarly, except for the feed-water systems used in each room. The justification for using separate rooms is provided below in the general management subsection.
The bottom of the SFWD system (Berry Feeding System, Greencastle, IN; manufactured by Lou Mfg., Inc, Austin, MN) included a flat area located below a plastic hopper and a sow-operated feed dispensing mechanism, and a shallow bowl area located below a water nipple. This allowed the sow an option of consuming dry or wetted feed. The sow-operated feed dispenser of the SFWD system included a rolling ball as the agitating mechanism that the sow used, and a knob that was inaccessible to the sow and used by the researchers to adjust the amount of feed flowing with each agitation by the sow. Feed passed from the hopper into the feeder when the sow moved the rolling ball dispensing mechanism.
The SFWD system was made of 3 materials: the feeder was made of stainless steel, the dispenser was made of PVC, and the hopper was made of polyethylene plastic. The dimensions of the SFWD feeder were: height, 54.6 cm without the hopper or 102.9 cm with the hopper; width, 41.6 cm; depth, 29.2 cm; lip to floor, 20.3 cm; and height of the bottom of the feed trough from the floor, 6.4 cm. The bottom of the HF feeder (Circle B Mfg. Inc, Three Rivers, MI) was J-shaped and free of corners in which feed could accumulate and spoil. All parts of the HF feeder that came in contact with the sow or feed were made of stainless steel. The dimensions of the HF feeder were: height, 69.2 cm; width, 36.2 cm; depth, 34.3 cm; lip to floor, 26.7 cm; and height of the bottom of the feed trough from the floor, 4.0 cm.
In both systems, the feeders were mounted to the head-gate of individual farrowing crates. Ad libitum access to drinking water was available in both systems. The nipple drinker (Jalmarson, model 1720-180A, Eskilstuna, Sweden) was approximately 8.0 cm above the shallow bowl, which was pressed into the bottom of the feeder used in the SFWD system. Water for the HF sows was provided using a nipple-cup combination, with the nipple fixed into the mounting wall of the cup. The nipple drinker (Edstrom, model 1000-0743, Waterford, WI) for the HF system was located 10.0 cm above the TriBar slatted floor, and to the left front side of each sow (10.0 cm from the feeder). The HF watering equipment was mounted to the left panel of the sow crate.
General Management
Feed-water systems were assigned to separate, adjacent farrowing rooms to assess most accurately the sow response to the feed and water systems. In a preliminary study (unpublished), the SFWD and HD systems were randomly distributed among the 12 farrowing crates within 1 farrowing room. We observed that sows on both systems stood and ate when HF sows were being hand-fed in the morning and afternoons. The eating behavior of the sows on the SFWD system appeared to be influenced by the management of the HF system. Believing that this was a violation of the self-fed or operant, ad libitum access concept, which we wanted to evaluate with the SFWD system, the 2 systems were placed in separate but nearly identical farrowing rooms for the current study. The facilities, equipment, and management, other than the feed-water system, were identical. Sows were not trained to use the feed-water systems before experimentation.
Environmental temperatures in the 2 farrowing rooms were maintained with thermostatically controlled heating and ventilation. Temperatures of the 2 farrowing rooms were set at 18 to 22°C for the study period and monitored daily. The thermostat was set at 22°C when farrowing began and was reduced gradually until it reached 18°C, by the end of the first week of lactation. It remained set at 18°C until weaning. Minimum and maximum temperatures were monitored daily (0830) at 30 cm above the floor. Within each replication, temperatures in the 2 farrowing rooms were similar (21.2 ± 0.1°C). For piglet warmth during the lactation period, a heat pad (Standfield, Model RS2B40, 50 x 90 cm, Osborne Industries Inc., Osborne, KS) was provided on the floor on 1 side of the sow in each crate. The same 24-h lighting regimen was used throughout the study in both rooms, with lighting from fluorescent bulbs during the day (0700 to 1700) and lighting from incandescent bulbs during the night.
Feeding Management
From entry into the farrowing room until parturition, all sows were offered 2.0 kg of the lactation diet once daily. Twice each day for the first 3 d postpartum, the sows were offered the same amount. Thereafter, the sows were fed to appetite until weaning (20 ± 0.2 d). After d 3 postpartum, feed was manually added to the hoppers of the SFWD systems 1 or 2 times (0800 or 1600, or both) daily so that fresh feed was constantly available. Fresh feed was placed in the hopper of the SFWD system when the quantity of feed remaining would potentially limit sow intake in the following 12 h. The HF sows were fed to appetite (an amount slightly exceeding the feed disappearance in previous meals) twice each day (0800 and 1600). Feed additions were weighed and recorded in the morning and afternoon on each day for each individual sow during lactation. At the end of the time period of d 0 to 6, d 7 to 13, and d 14 to weaning, all residual feed in the feeder, including the feed in the hopper of the SFWD system, was collected and weighed to determine total feed disappearance. Sows were fed 2.3 kg of the gestation diet once daily from weaning to estrus.
Sow Performance
Total feed disappearance was determined over the entire lactation period for each sow. Sows were weighed within 24 h after parturition, on d 7 and 14 postpartum, and at weaning. Sow backfat depths were measured using a digital backfat indicator (Lean Meater, Renco Corp., Minneapolis, MN) on d 0 and at weaning at 5 cm to the left and right of the midline at the 10th rib. Standing heat in the presence of a boar was used as an indication of postweaning estrus. Several different boars were used rotationally, and exposure was 2 times each day.
Piglet Growth Performance
By d 3 postpartum, litters were standardized to have a minimum of 10 piglets per sow by cross-fostering. The number of piglets within a litter and piglet BW were recorded at birth, at cross-fostering, and on d 7, d 14, and at weaning. The CV for individual piglet BW within litter was calculated for each weighing day to evaluate the effect of treatment on piglet growth variation within a litter. No creep feed was provided before weaning.
Feed and Water Intake
To document feed and water intake of lactating sows, custom-built water tanks and feed and water wastage collecting systems were used to record water disappearance and to collect feed and water wastage. In each of the 5 replications studied from September 2003 to January 2004, 5 or 6 sows from a treatment group in a replication were randomly allotted to crates 7 to 12 of each room and used to more accurately determine actual feed and water intakes. The water supply to crates 1 through 6 in both farrowing rooms was via standard plumbing within the barn (41 to 48 kPa). Sows in crates 7 through 12 in both farrowing rooms received their water from individual, pressurized (41 to 48 kPa) water tanks, which were designed to hold 42 to 43 L of water and which allowed measurement of water disappearance for sows in those crates.
The nipple drinker, water flow rate for the 2 rooms was adjusted to 1.0 to 1.4 L/min under a water pressure of 41 to 48 kPa. Water disappearance was recorded at 0800 and 1600 daily. The water tanks were refilled after each measurement of disappearance. Custom-fabricated systems to collect wasted feed and water were installed under the TriBar slatted floor of crates 7 through 12 in both farrowing rooms. Each crate had a separate collection unit, which consisted of a screen, a pan, and a carboy. The screen was set in the pan, and the carboy was fitted under the pan. This allowed separation of wasted water from the wasted feed for each sow. Wasted water drained through the screen onto the pan, where it then followed a designed slope into the carboy. Collection units were mounted on garage door tracks under the feeding and watering areas of the sow beneath the crates.
Wasted feed was collected on a 1- to 3-d basis (0800) throughout lactation, with wasted water collected twice daily (0800 and 1600). Carboys containing wasted water were weighed at the farm immediately after collection and were then emptied. Wasted feed was collected and transferred to labeled aluminum pans. The labeled aluminum pans were covered and transported to the laboratory, where DM of the waste feed was determined by oven dying for 24 h at 100°C and then was extrapolated back to as-fed moisture (12% moisture). The difference in the amount between the original weight of the waste feed and its as-fed feed weight was added back into the amount of waste water. Care was taken to avoid collection of piglet and mice feces, although minor contamination was unavoidable.
After each collection, the waste collection equipment was scraped, brushed to clean off any residue, reassembled, and placed back under the crates. Average daily feed intake was calculated as total lactation feed disappearance per sow minus total lactation feed waste per sow divided by lactation length. Total lactation feed waste as a percentage of the total feed disappearance was also calculated for each sow. Average daily water intake was calculated as total lactation water disappearance per sow minus total lactation water waste per sow divided by lactation length.
Statistical Analysis
Sow feed disappearance and lactation performance data were collected for all sows (n = 114). Feed and water intake and wastage data were collected on a subset of those sows (n = 58). Piglet growth performance was evaluated using BW recorded on d 7, 14, and at weaning. Piglet BW at birth and at cross-fostering were not analyzed because the exact date of weighing was inadvertently not recorded for several litters.
Thirteen of the sows on the HF system were not included in the analysis of the water wastage and average daily water intake data because of unanticipated water wastage in excess of the carboy capacity. Water wastage in excess of the carboy capacity did not occur with the SFWD system. Two outliers were detected using the Studentized outlier test for the feed wastage data, but data were included in the final analysis because there were no biological reasons for their removal.
Data were analyzed by ANOVA using PROC MIXED (SAS Inst. Inc., Cary, NC) for a completely randomized design, with the sow and piglet serving as the experimental unit for sow and piglet parameters, respectively. The models for the sow and piglet parameters included fixed effects of treatment and parity, as well as the treatment x parity interaction. When appropriate, non-significant interactions (P > 0.25) were pooled into the appropriate error terms for the final models.
Lactation length was included as a covariate in models analyzing sow total lactation feed disappearance, d 14 to weaning feed disappearance, water disappearance, feed wastage, water wastage, sow BW at weaning, sow BW change from d 0 to weaning, weaning backfat depth, backfat depth change during lactation, weaning-to-estrus interval, CV of piglet BW within litter at weaning, piglet BW at weaning, and piglet BW gain from d 14 to weaning. Litter size was included as a covariate in models analyzing total lactation feed disappearance; weekly feed disappearance; water disappearance; feed wastage; water wastage; feed intake; water intake; sow BW at d 7, 14, and weaning; sow BW change during lactation; weaning backfat depth; backfat depth change during lactation; weaning-to-estrus interval; piglet survival; CV of piglet BW within litter; piglet BW at d 7, 14, and weaning; and piglet BW gain from d 7 to 13 and d 14 to weaning. Sow BW at d 0 was included as a covariate in models analyzing sow feed and water disappearance, feed and water wastage, and feed and water intake, as well as subsequent sow BW. For the above covariates, if more than 1 covariate was mentioned for a given parameter, all were included in a single covariate model.
Random effects in PROC MIXED for sow parameters included replicate, replicate x treatment, and replicate x treatment x parity. Random effects for piglet parameters included replicate, replicate x treatment, replicate x treatment x parity, and sow (replicate x treatment x parity).
Chi-square analysis was used to evaluate the effects of feed-water system on the occurrence of estrus by d 11 postweaning.
All means presented are least squares means. Differences were considered significant at the level of P < 0.05.
| RESULTS AND DISCUSSION |
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Sow BW at d 0, d 7, 14, and weaning were not different between treatments (Table 2
). Both groups of sows gained BW during lactation, with those on the SFWD system gaining more from d 0 to weaning (P < 0.01). Sows in both groups lost BW between d 14 and weaning, suggesting a metabolic use of body tissues and the inability of either feed-water system to provide sufficient nutrients for milk production and litter growth at the end of lactation. Peterson et al. (2004)
reported no difference in BW change during lactation when comparing self-fed and hand-fed feeding. The studies of Whittemore et al. (1988)
, Mahan (1998)
, and Spencer et al. (2003)
, although not designed to compare methods of feed and water provision, likewise observed sows gaining BW during lactation, when BW change was calculated using weights taken immediately postpartum and at weaning. Although BW change in the current study suggests differing amounts of body tissue mobilization during lactation, subcutaneous backfat depth at weaning and backfat change from d 0 to weaning were not different between treatments. In contrast, Peterson et al. (2004)
reported less backfat loss during lactation with greater feed intakes when using of the self-fed mechanism. Conservation of sow BW or tissue during lactation is thought to be important because it is related to the culling of highly productive sows because of post-weaning anestrus or failure to conceive after weaning. However, despite the greater BW gains of SFWD sows in the current study, feed-water system did not influence weaning-to-estrus interval or the percentage of sows that displayed estrus postweaning. The current study only included one lactation, and the potential impact of the intake options provided the sow with the SFWD system on long-term reproductive performance over multiple parities is worthy of further investigation.
Piglet Growth Performance
Litter sizes at cross-fostering, d 7, d 14, and weaning were not different between HF and SFWD treatments (Table 3
). Likewise, feed-water system had no effect on litter survival from cross-fostering to weaning or on the CV for piglet BW within litter at any time from cross-fostering to weaning. Piglet BW on d 7 and 14 were not different, but at weaning, the SFWD piglet BW was 0.51 kg greater (P < 0.01) than that of the HF piglet. Piglets nursed by SFWD sows had greater ADG from d 7 to 13 and from d 14 to weaning (P < 0.01 and P < 0.01, respectively) compared with those nursed by HF sows. Within treatment comparison of piglet ADG between periods showed that piglets of SFWD sows increased gain from mid to late lactation. However, the ADG of HF piglets was 254 and 254 g/d for the same 2 periods, indicating that milk production of sows on this treatment did not increase enough to promote piglet ADG in the later period of lactation. Treatment differences in piglet growth reflected similar treatment differences in feed disappearance, suggesting that the SFWD sows were producing increasing amounts of milk as lactation progressed. In contrast, in the studies of OGrady and Lynch (1978)
and Koketsu (1994)
, no improvement in litter growth was reported when a wet feeding system was used, despite observing an increase in apparent feed consumption by sows.
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Daily water requirement during lactation varies from 15 to 35 L (Thacker, 2001
). The results of the current study are within this range but are much closer to the lesser requirement suggested. The wide range of water requirement reported by Thacker (2001)
may in part be the consequence of water disappearance measurement rather than actual water intake. For example, Seynaeve et al. (1996)
and Farmer et al. (2001)
reported water intake but did not take into account water wastage.
In this study, the amount of water wastage of the HF sows was more variable than that of the SFWD sows. Drinkers located inside the SFWD system resulted in an average of 15 L of waste water per sow during the entire 20-d lactation period. Comparatively, about 15 times more water was wasted per sow on the HF system. If the goal of a commercial swine operation is to reduce the amount of slurry or manure by limiting water waste by the animals, then the large amount of waste water with the HF system would be a concern. As an example, a 2,400-sow production unit would waste at least 1,362 t more water per year using the HF feeding system.
| IMPLICATIONS |
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| Footnotes |
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2 Current address: Department of Youth Development & Agricultural Education, Purdue University, West Lafayette, IN 47907. ![]()
3 Current address: Cargill Innovation Center, Elk River, MN 53330. ![]()
4 Corresponding author: rozeboom{at}msu.edu
Received for publication July 18, 2006. Accepted for publication October 26, 2006.
| LITERATURE CITED |
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