Water Quality for Dairy Herds - Case Histories from Pennsylvania

William E. Sharpe, Ph.D., Professor of Forest Hydrology, The Pennsylvania State University
Richard S. Adams, Ph.D., Professor Emeritus of Dairy Science, The Pennsylvania State University

Introduction

Today's dairy cows are finely tuned milk producing machines that require a perfect balance of nutrition and adequate water intake to perform at peak levels. Although water contributes very little to the cow's nutrition, it is essential to the production of milk, which is mostly water. When water intake is below normal, milk production suffers. If the quality of water is such that normal rumen function is upset, milk production will also be reduced. Finally, if water contains toxins in sufficient quantity, the cow's health may be adversely affected and death is a possible outcome.

Existing water quality standards for dairy cows are inadequate and often of very limited diagnostic value. For example, if one endeavors to determine the effects of excess manganese in the water being supplied to a dairy herd, one of the best references available contains the information that no limits are available for manganese since sufficient experimental data are not available (NAS 1974). The date of this reference points to another significant problem. Summaries of available toxicological information are almost all out of date. In fact, one of the best ones available (McKee and Wolfe 1963) is long out of print and out of date. Data on new chemicals in water and current summaries of available information are sorely needed.

How does one interpret water quality data in the context of herd health? There are a few obvious problems that are relatively easy to decipher and many others that are very difficult to resolve. Some of the former would include excessively low or high pH, gross bacterial contamination, very high sulfates, and foul smelling or tasting water. Beyond these there is a relatively large void in current knowledge and one is left to play a game of trial and error elimination in hopes of isolating problems.

If a water quality problem is not readily apparent, the first step is to look at water preferably by metering the supply. If intake is low, a possible problem with water quality may exist. The next step is to place several animals on a different source of water known to be problem free. If water intake as well as the general condition of the animals e.g. milk production increases, then water is implicated and a more thorough water analysis is usually indicated. If this analysis turns up high levels of a particular contaminant, it is assumed that it is the problem even when specific toxicity information is unavailable.

Case Histories

Experience is the most valuable asset in diagnosing water quality problems associated with animal health. The following case histories will give the reader benefit of our experience and hopefully assist in the diagnosis of water quality related dairy health and production problems. Only case histories with successful problem resolutions are included.

Centre County, PA 

Case One

A fanner complained of low milk production in his dairy herd. Years previously he had abandoned a spring due to gasoline contamination from a storage tank on the premises and drilled a well. The well-yielded "sulfur" water, which is the local colloquialism for hydrogen sulfide (H2S), dissolved in water. The problem was worse following prolonged dry spells indicating that the sulfide bearing rocks were nearer to the bottom of the well than the top. Analysis confirmed H2S and an experimental H2S removal system was installed (hydrogen peroxide injection) and the problem solved. Milk production rose substantially. A short time later, a different solution was put in place. As a result of a drought, the H2S contaminated well went dry. A new well was drilled located on fracture zones and the H2S bearing rock formation was avoided by controlling drilling depth.

Case Two

A widow was attempting to continue dairying following the sudden and unexpected death of her husband. Daily water intake was about 17 gallons/cow/day with milk production between 63-68 lbs./cow/day; however, sudden drops in milk production to as low as 55 lbs./cow/day had previously occurred. In order to boost production, water was trucked in for the cows. Milk production was much better on the hauled water. Analysis indicated an iron problem even though an iron treatment and ultraviolet light (disinfection) were in place. In talking with the dairywoman, it became obvious that the problem was potentially more complicated than iron. The ungrouted well was immediately adjacent to the milk house and silo. The bedrock around the well was fractured and solutionalized limestone. Silage juice and milking parlor wastes were suspected of flowing directly into the well. Due to the difficulty inherent in treating such pollutants, conventional treatment was out of the question. A new well was sited and put into production some distance up the groundwater gradient from the existing well and the problem was solved.

Franklin County

Case One

A dairy producer had multiple problems with the quality of his water supply. Among these were a pH that was slightly elevated (8.0), high iron and high manganese. Muriatic acid was added to the water to reduce the pH to 6.8. Subsequently, milk production improved by 5.4 lbs./cow/day. An improvement in milk production as a result of adjusting pH 8.0 water was puzzling because pH 8.0 water should not have been a problem. This water was also highly contaminated with coliform bacteria (1,930/100 ml). Correction of the bacteria problem, which results in off-feed problems (feed consumption later increased by approximately 30 percent), could also have accounted for the production gain. In fact, if chlorination were in use for bacteria control as had been recommended earlier, a reduction in pH to 6.8 would have improved treatment effectiveness and this may have accounted for the gain rather than the pH adjustment. This case illustrates the sometimes-complicated nature of water treatment.

Case Two

A dairy farm in the southern part of the county reported production problems associated with high bacteria counts. A visit to the farm and an inspection of the water system revealed a cartridge-type particulate filter that was clogged with what appeared to be pieces of manure. The farm was situated on a limestone outcrop and had a relatively new in ground manure storage that had required some blasting to remove rock during excavation. Roof runoff was channeled to the manure storage and the storage was never observed to overflow. It seemed highly likely that the well and the manure storage were hydraulically connected over the relatively short distance between them. The producer was advised to direct roof runoff water away from the storage pit and to put a liner in the bottom of the manure storage or discontinue using it. Unfortunately, no information on milk production was available for this operation.

Berks County

 Another example of potential mistaken identity involved a dairy producer who had installed a rather expensive ion exchange nitrate removal system on the recommendation of a local vendor of such equipment. A noticeable improvement in milk production became apparent shortly after the equipment was in place. The producer attributed the increased production to the nitrate removal system even though nitrate concentrations in his water supply were well below problem levels. On an ensuing farm visit, it was discovered that water prior to treatment was fouled by H2S while the water after treatment was not. An unexpected side benefit, albeit a costly one, of the nitrate removal was H2S removal as well. The producer was informed of this and subsequently ceased nitrate removal while maintaining H2S removal without suffering a drop in production.

Somerset County

A dairy fanner in an area of active bituminous coal surface mining and bio-solids reclamation requested assistance with a dairy herd producing on the order of 20 lbs. of milk/cow/day. A visit to the farm revealed active mining within 500 feet of the well and thin, anemic cows with loose manure. The veterinarian's report indicated that the cows were suffering from "abortion, anemia, poor utilization of feedstuffs, substandard reproductive performance and above average susceptibility to disease." These problems could not be explained by blood analysis and pathology. The cows were consuming an average of 13 gallons of water per cow per day. When these cows were placed on a different source of water, milk production improved dramatically. Water analysis revealed high iron and manganese typical of acid mine drainage pollution. In addition, zinc and lead were high in some analyses. The pH of the water was highly variable. The presence of the zinc and lead did not appear to lead to any outright pathology. Iron concentrations were as high as 10 mg/l and Mn concentrations were also high at 0.31 mg/I. These levels almost certainly adversely affected the palatability of this water supply and were responsible at least in part for the low water intake. We attributed the lead, zinc and fluctuating pH to the mine reclamation activities in the area. The farmer sued the mine operator and, in what was hailed as a landmark case for Pennsylvania, won a monetary judgement.

Summary

The case histories presented represent some of the more clear-cut examples of water quality related dairy herd production problems. Unfortunately, we still know very little about the toxicity to dairy cattle of many of the more recently discovered organic groundwater pollutants, such as industrial solvents. Similarly, the combined effects of various pollutants are poorly understood as well as the precise thresholds of toxicity for all pollutants, even the more familiar ones. Lastly, a thorough review of the available literature is absolutely necessary to provide an up-to-date reference for workers in the field.

We know mostly from our experience that pollution from mining activities resulting in high sulfates, iron, manganese and sometimes aluminum is a serious problem for dairy producers resulting in poor animal health, low water intake, and poor milk production. Indeed, acid mine drainage has forced some producers completely out of business. Low pH from whatever cause is also a significant problem resulting in acidosis and loss of milk production. Hydrogen sulfide (H2S) in water reduces water intake and milk production and its removal by treatment has been shown to be of benefit. Likewise, even relatively low levels of coliform bacteria sometimes result in off-feed and ketosis problems.

Our experience also indicates that anything that you can smell or taste in water is a potential palatability problem for dairy cattle. Water quality may vary considerably in space and time and this should be considered when interpreting water analyses. If initial water analyses do not indicate any obvious problems, animals should be given water from another source (preferably of high quality) and their performance monitored. Improved performance may then warrant a more exhaustive suite of water analyses. It is always helpful to know what pollutants match up with what land use activity. This aids in the specification of water analysis. A site visit and producer interview are usually essential to unraveling water quality related problems. In cases of gross contamination, the contamination source is usually very close to the water supply. Multiple expertise is often required to solve complex problems. And finally, there are no free lunches and there are no miracle cures for water quality problems.

Literature Cited

Adams, R.S. and W.E. Sharpe. Water Intake and Quality for Dairy Cattle. Dept. of Dairy and Animal Science, The Pennsylvania State University, 324 Henning Building, University Park, PA, 16802. DAS 95-8. 7 p. (1995).

McKee, J.E. and H.W. Wolf. Water Quality Criteria (second edition). State of California State Water Quality Control Board, Sacramento, CA. 548 p. (1963).

National Academy of Sciences. Nutrients and Toxic Substances in Water for Livestock and Poultry. Washington, DC. 93 p. (I 974).