Interaction between water and reproduction

Dr John Carr

Water is obviously essential for life. A sow will die within 4 days if she does not receive any water. Normal sows are used to living in an environment where there is a plentiful supply of water and she normally produces poorly concentrated urine, a normal urine concentration will have specific gravity of 1.000 to 1.010 where as humans are much better at concentrating urine (normal specific gravity 1.030).

What are the normal requirements for water in adult sows?

Daily requirement

Animals are 70% plus or more water, at birth piglets have a higher water content. In general terms pigs will use 1 litre of water for each 10 kg body weight, again younger animals use more, older animals require less. Therefore, a non lactating 200 kg sow could theoretically use 20 litres per day - which is in excess of majority of advice sheets of 8-10 litres per day.

Why is there this difference? Predicting a sow's daily requirement is frustrated by:

a) Measuring usage not requirement. A lot of drinkers are very wasteful - up to 40% of water from a lot of drinkers is not swollowed by the pig.

b) The amount required per sow varies between days and between sows. In my own work, clinically healthy non lactating sows will drink 6 to 12 litres per day.

c) Requirements will vary with the seasons, in the hot summer the daily intake will be greater.

d) The requirement is related to feed intake. This can have a significant impact on availability of water for the lower order sows.

e) Health or disease can have an impact in individuals. Chronic kidney problems can be common on pig farms and if the kidneys are damaged the animals will require more water as they are unable to concentrate their urine. One such sow with chronic kidney failure required on average 125 litres per day (range 85-140 litres per day personal observation).

Finally, in lactation, the water requirement increases tremendously. At peak lactation (around day 18) milk output of the modern sow will be 12-14 litres of milk. Therefore, the requirement of the healthy sow for water during lactation increases to 40 to 80 litres per day.

Therefore in summary, on average the healthy dry sow requires 12 litres of water per day, the healthy lactating sow requires 40 litres of water per day.

Drinker provision

To provide the daily water requirement, a drinker needs to be provided which will allow the sow to easily obtain her daily requirement with minimal waste. There are a number of features, illustrated in figure 1, to bear in mind. Three specific points to note: a) The flow of water through the drinker. From a nipple or bite drinker provide 2 litres per minute (minimum 1.5 litres per minute). This means that dry sows obtain their daily water intake in 6 minutes and a lacating sow takes 20 - 30 minutes. How long do you drink each day? Research has shown that weaners may only spend 3-4

minutes drinking each day. In a trough scenario a sow will drink 3 litres in 45 seconds. b) Height of the drinker. For sows a nipple or bite drinker should be placed at 75-90 cm from the floor. Note the drinker needs to be easily accessible and not shielded or hidden by other equipment. c) Drinkers should be 2 metres apart in loose housed sows to prevent one sow dominating the drinking system.

How can water specifically affect reproduction?

There are four specific conditions to consider.

a) Cystitis and pyelonphritis

b) Gilt vaginal and vulva mucosal sloughing

c) Poor wate quality

d) Lactation feed intake

e) Water for body temperature control

Cystitis and Pyelonephritis

Cystitis is infection of the bladder and when it damages the ureterovesical valves, infection ascends to the kidneys resulting in pyelonephritis.

The agents isolated from cases are primarily bacterial, associated with Actinobaculum (Eubacterium,) suis, Escherichia coli (E. coli) and streptococci. All of these are very common either in the environment or in the prepuce of the boar. The disease occurs when the defence mechanisms of the bladder is affected. The defence mechanism of the bladder is primarily influenced by poor urination. Water availability has an impact on the sow's urinating patterns. Because this disease is a combination of poor enviroment and behaviour, the disease is seen in adult sows, particularly those older than parity 3.

The clinical signs depend on if the bladder only is affected or where there is damage to the kidneys as well. If the bladder only is affected (cystitis), the clinical signs can be minimal with only the production of smokey urine, some pain response and frequent urination, many of these signs the average stockperson will miss. Note some 70-90% of sows in the farrowing house may have histological evidence of cystitis.

Once the disease affects the kidneys the clinical signs can be dramatic and sudden. In acute pyelonephritis cases the sow will be a few days post-breeding. She may appear to be urinating frank blood, off food, collapsed, hypothermic or may be found dead. Death can occur with hours of any presenting signs. Recovery is unlikely. Alternatively the sow may have chronic pyelonephritis, which can occur at any time in her reproductive cycle. She will be urinating smoky to red/blood urine. The sow will be toxic and this creates rapid breathing, off food, weakness in hind legs, collapse and death. The major affect on reproduction is death of the pregnant sow. Majority of sow's with pyelonephritis will be pregnant and therefore the farrowing rate is reduced, on specific farms this has accounted for a 10% reduction in the farrowing rate. There may also be some reduction in litter size associated with excessive toxins which have not been cleared from the

Figure 2 Kidney with chronic pyelonephritis - the white/grey areas, the darker areas are still functioning kidney

body by the affected kidneys, but this is only apparent in severe chronic cases.

Treatment routines

Individual sows

Loose house the sow and provide exercise (forced if necessary) to encourage urination. Provide continuous access to troughed water. Use of antibiotics such as a combination of lincocin and tetracycline by intramuscular injections can be very useful. Note in acute cases the sow can die very rapidly.

Herd treatment

Water and urination

It is essential to encourage regular and frequent urination. During the problem period check all sow's post-service (0-28 days) for any blood in her urine. Treatment is more effective when a case if descovered early. Ideally feed or heat check the sows twice daily to encourage the sow's to rise and urinate in the afternoon.

Improve water availability to provide water at a flow rate of 2+ litres per minute. One way to check if the water supply is adequate, is to enquire about the average sow feed consumption on day 18 of lactation, which should be approaching 10 kg per day. Regularly maintain water supplies and record that the examination has been carried out.

Farrowing house management

Limit any trauma and infection of the vagina and bladder, improve hygiene behind the sow by manually removing faeces 3 days prior and 7 days post-farrowing. Very dirty rear regions should be cleaned with soap and water. Reduce manual farrowing as much as possible, and if it is necessary use plastic gloves and clean hands. All sows manually farrowed should receive appropriate antibiotics. Encourage the correct use of oxytocin where appropriate. Ideally increase lactating length to 24 days to allow for any damage to the bladder and vagina, which occurred at farrowing, to heal by the time the sow is rebred.

Breeding area hygiene

At all times stalled sows must be separated for her urine and faeces. Clean all soiled rears of the sow particularly prior to service. Avoid contact with the boar's penis during service. Ensure that the underline of the boar is kept clean by managing the boar in a clean dry environment. Ensure service is carried out on a good non-slip floor. Do not serve lame sows with boars, only use AI.

Gilt vagina and vulval mucosal sloughing

Puruent vulval dischages and water availability has been difficult to associate. Majority of 14-21 day vulval discharges, which result in failure of pregnancy, are associated with breeding management rather than specific water issues. However, cases of vulval discharge in gilts (bred and unbred) have been seen which are associated with farrowing rates below 60%. The characteristic of these animals were that they were subjected to long distance transportation without water and then were bred within 10 days of arrival on to the farm. The transportation distances varied, but in three cases they were 1500 miles over land. The animals presented clinically weak, dehydrated but otherwise fit. Examination of their external genitalia revealed swelling, congestion and sloughing of the internal mucosa of the vulva and vagina. The lining of the vulva and vagina were very dry and no natural lubrication could be elicited. The genital injuries healed within 2 weeks of arrival following normal care. However, of the gilts which were bred within 10 days of arrival, 20% presented with a very purulent vaginal discharge within 2-3 weeks of breeding, the farrowing rate in the remaining was only 60% with a resultant poor litter size, however, their genitalia recovered. Ceasation of breeding immediately post-arrival restored the normal reproductive parameters and changes in the transporation protocols, allowing time to stop and provide water and allowing gilts the ability to urinate naturally, stopped the drying of the vulval and vaginal mucosa.

Poor water quality

This is a very poorly documentated area. However, without scientific proof, there are several cases where reproductive problems have persisted over a long period of time (low farrowing rates -65% and low litter size -10.5 live born) have suddenly been resolved by the use of municipal water supplies as compared to the bore hole water previously used. No specific investigation into the differences in water quality have been carried out or no specific differences were noted, given the range of tests carried out. However, water quality is an area where investigations are required and from time to time can make a significant difference to the performance of the breeding sow.

Lactation feed intake

There are many factors that can affect lacatation feed intake. Clinically there are three major areas which should be examined first as they have the biggest impact (in my opinion): Water provision; farrowing house temperatures (day and night) and the health of the sow.

Water and lactation feed intake has received scant research. What research has been done has been contraversial with several trials indicating little correlation between water and feed intake. However, most trials have used nipple or bite drinkers which automatically limit the sow's ability to drink or fail to standardise the availability of water, merely stating 'water was freely available' which is little more than meaningless.

In my own studies average sow lactation feed intake over a 24 day lactation has progressed from 5 kg a day with a peak intake of 6-7 kg at day 18 through the feeding of dry lactation feed (18% protein 1% lysine 14 MJ DE) to 6.8 kg a day with a peak intake of 9-11 kg at day 18 using the same feed. Recent studies on liquid feeding (using a very similar formulae for the feed on a per dry matter basis) has resulted in increasing average lactation intakes to 8 kg a day with a peak intake of 11-14 kg on day 18. The weaning weights of the piglets have closely matched the average lactation intake. With liquid feeding over 100 kg of piglet weaned have been achieved per sow per weaning. On all these farms no other change in farrowing house design, genetics or basic stockmanship occurred. The impact on reproduction has been more difficult to assess. The farms where these results have been obtained are non-reseach farms where many other parameters are changed or moulded over time to maintain output. On all of the farms the reproductive results were good to excellent, with farrowing rates 82% or above, total born 12.5 or above, the number of piglets weaned being in excess of 10 per sow per litter. However, from time to time, despite the lactation feeding regimes, reproductive performance also failed, associated with, for example; bouts of poor health, stockmanship errors or seasonal influences.

Water for body temperature regulation

The pig is unable to regulate its body temperature through sweating, as sweat glands are very localised in the pig, on the carpus for example. Body temperature regulation is primarily through behaviour and panting. In hot climates being able to avoid the heat and humidity may be impossible, particularly with the development of large pig farms utilising European genetic coupled with little provision for the sow and boars to turn around. Therefore the necessary microenvironment must be provided. Reseach again is sparse and a large reliance on clinical observation is required. General advice can be given and has proved to be sucessful in practice.

Boars

The boar is particularly sensitive to temperature effects on semen output and quality, with a marked decrease in output and an increase in abnormal sperms been seen in the hotter weather. Of interest is how the semen quality will vary over the day with reasonable quality sperm being obtained in the cool morning and very poor quality sperm being obtained in the heat of the mid-afternoon. Boars subjected to an ambient temperature of 30C for 2 days can have poor semen output for the next 6 weeks and some of the animals do not recover from the heat stress.

Sows

Lactating and pregnant sows will reduce their feed intake (depending on feeding routines) if they are subjected to heat stress. This will result in loss of maternal bodyweight and in lactation a reduction in litter weaning weights. The effect on reproduction is more difficult to analyse as the effects can be transient. However, effects of loosing weight in lactation can extend the sow's weaning to breeding time, which has negative reproductive consequences.

Outdoor sow enjoing a mud wallow

If pregnant sows are sufficiently temperature stressed they can abort. However, note that this can be associated with excessive heat stress, but also poorly cooled sows which are damp and subjected to excessive air movement can result in too much cooling, the chilling will result in abortion. In outdoor systems, even in temporate climates, adequate cooling provision through mud wallows are essential to assist in reaching acceptable reproductive performance.

Summary

Water is an integral part of the sow's requirement for survival and yet is often overlooked in the normal daily routines. Water plays many roles in the sow and in the specific case of reproductive performance if clear drinking water is not provided in sufficient qaulities can specifically influence

a) production through the death of the pregnant sow with pyelonephritis,

b) interfer with the gilt's ability to breed though changes in the vaginal and vulval mucosal integrity,

d) affect lactation feed intake,

e) affect boar semen production and sow mating abilities through lack of cooling and

f) in an undefined way affect reproduction in general through poor water quality.