Research trials bear out the value of water-based medications in treating segregated early weaning nurseries.

Researchers at Kansas State University (KSU) recently conducted a series of trials to evaluate the effectiveness of replacing feed-based antimicrobials with water-based products in segregated early weaning (SEW) nurseries.

Lead researcher Russell Gottlob and KSU colleagues tackled the comparisons at the request of a commercial pork producer who was interested in eliminating the challenges associated with mixing antibiotics in the feedmill, yet was unwilling to sacrifice the improvements in growth rate found with growth-promoting antibiotics.

The producer's concerns centered on three key issues:

  • Feed processing limitations make it difficult to change antimicrobials used;

  • The use of multiple antibiotics in the mill requires multiple runs and adds to concern about cross-contamination with non-medicated feeds; and

  • Pulsing antibiotics can be very difficult in feeds due to difficulties in timing deliveries.

The goal of the KSU experiments was to study the feasibility of replacing in-feed antimicrobials with water-based antimicrobials to simplify these processing and handling challenges and reduce the risk of feed contaminated with inappropriate antimicrobials or residues.

Preliminary Trial Provides Guidance

An initial study involving 350 weaned pigs, averaging 13 lb. and ranging in age from 11 to 17 days of age, was conducted to determine the effects of a water-based antimicrobial on pig performance in the nursery.

Pigs received one of five different treatments — three with water medications consisting of Neomycin sulfate, Oxytetracycline or a combination of the two; another with Neomycin sulfate-Oxytetracycline HCl in the feed; and a “negative” control diet with no feed or water medications.

SelectDoser peristaltic pumps (Genesis Instruments), which are powered by electricity, siphoned a concentrated, pre-mixed stock solution through a tube and dosed the medication into the existing water supply.

At the close of the 28-day nursery trial, researchers reported that pigs receiving antimicrobials in water had higher average daily gain (ADG) and average daily feed intake (ADFI) than pigs that received no medication in feed or water. However, pigs receiving feed-based antibiotics outperformed pigs receiving the water-medicated options.

The KSU researchers noted that water usage was much higher than expected. Typical water disappearance is around 20% of pig body weight (BW) using bowl drinkers.

In this experiment, water disappearance was highest the first week, approximately 36.4% of BW, which gradually tapered off to 22.8% by Day 28. The excess was attributed to pigs playing with the nipple waterers and water spillage while drinking. This confounded the experimental results because water antimicrobial levels were based on predicted consumption without factoring in water wastage.

Consequently, pigs receiving antimicrobials in water “most likely did not receive the desired level of antimicrobial per pound of body weight,” Gottlob explains. “Furthermore, pigs provided antimicrobials through the water received an overall lower dosage compared to pigs provided antimicrobials through feed.”

“This preliminary trial told us that we could improve performance with water-based antibiotics, but that we needed to work further on the dose and delivery to ensure an adequate quantity of antibiotic was reaching the pig,” explains Mike Tokach, KSU Extension swine nutritionist. “The second trial really tells the whole story.”

Follow-Up Study

Bowl drinkers were installed in the same facility to reduce water wastage in the second trial and ensure pigs received the prescribed antimicrobial levels. This follow-up experiment also examined more antimicrobial levels in the water.

A total of 360 weaned pigs, averaging 14.1 lb. and ranging in age from 21 to 24 days of age, were given one of eight experimental treatments, including:

  1. Negative control (no antibiotics in feed or water).

  2. Positive control with Neo-Terra-mycin in the feed (140 g./ton Neomycin sulfate, 140 g./ton Oxytetracycline HCl).

  3. 38 mg. of Neomycin sulfate/liter of water.

  4. 75.5 mg. of Neomycin sulfate/liter of water.

  5. 113.5 mg. of Neomycin sulfate/liter of water.

  6. 100 g./ton of Neomycin sulfate in feed.

  7. 200 g./ton of Neomycin sulfate in feed.

  8. Combination of treatments 2 and 4 (Neo-Terramycin in feed and 75.5 mg. of Neomycin sulfate/liter of water).

Five pigs were placed per pen with nine pens per treatment. The SelectDoser was again used to dose the medication into the water supply. The stock solutions were dosed at a 1:100 ratio to achieve the desired level of medication. Each solution also contained citric acid as a water line cleaner and drug solubility aid. Medication concentrations were based on an estimated consumption of 10% of pigs' body weight, rather than disappearance. Pigs stayed on the same treatment for the 24-day test period and were weighed on Day 7, 14 and 24.

Two dietary treatments were fed, ad libitum, in meal form, with the Phase I diet fed the first 14 days and Phase II fed for the balance of the 24-day trial.

The phase I diet was formulated to contain 1.41% true ileal digestible (TID) lysine, 0.90% calcium (Ca), and 0.50% available phosphorus (P). Phase II diets were formulated to contain 1.31% TID, 0.83% Ca, and 0.39% available P.

Pigs receiving the various treatments (2 through 8) outperformed those receiving the negative control diet, when measuring average daily gain (ADG), average daily feed intake (ADFI) and lb. feed/lb. gain (F/G).

Pigs receiving Treatment 8 had greater ADG and ADFI than pigs fed Treatments 2, 3, 4 and 5. Researchers also noted that increasing Neomycin sulfate in the water (Treatments 3-5) improved ADG and ADFI. Likewise, increasing Neomycin sulfate levels in the feed (Treatments 6 and 7), improved both measures, plus F/G.

Pigs provided Treatment 8 had greater ADFI and tended to have greater ADG than pigs fed Treatment 2 or pigs receiving Treatment 4.

Generally, whether Neomycin sulfate was supplemented through feed or water did not affect the beneficial performance response to antibiotics.

“No differences were found in growth performance of pigs provided medication using either method,” Gottlob explains. “This indicates that water-based medication can be used in place of medication in the feed to yield similar growth performance.”

Table 1. Growth Performance of Early Weaned Nursery Pigs Provided Neomycin Sulfate in the Water and Feed.a
Probability, P<
Neomycin sulfate mg./L water Neomycin sulfate, g./ton feed Negative control vs. Positive control vs. Combo vs water Neo 75.5 Feed med vs. water med
Item Neg control Pos conb 38.0 75.5 113.5 100 200 Comboc Pos control Water med Feed med Water med Feed med Combo
D 0 to 24
ADG, lb. 0.81 0.89 0.91 0.89 0.90 0.91 0.93 0.95 0.02 0.01 0.01 0.78 0.36 0.09 0.06 0.38
ADFI, lb. 1.07 1.14 1.16 1.13 1.16 1.17 1.18 1.23 0.05 0.01 0.01 0.83 0.35 0.04 0.02 0.33
F/G 1.33 1.28 1.27 1.27 1.29 1.29 1.26 1.29 0.11 0.03 0.05 0.84 0.89 0.85 0.61 0.96
aA total of 360 weanling pigs, initially weighed 14.1 lb. and 21 ± 3 d of age (PIC L337 × C22). Values are the mean of nine replications.
bContaining Neo-Terramycin® (140 g/ton Neomycin sulfate, 140 g/ton Oxytetracycline HCl).
cContaining Neomycin sulfate in the water (75.5 mg/L) and Neo/oxy in the feed (140 g/ton Neomycin sulfate, 140 g/ton Oxytetracycline HCl).