Better Pork - October 2005

What's behind the surge in fall abortions?

Decreasing daylight hours, temperture fluctuations and low progesterone levels seem to be the culprits. Some remedies if your herd is affected

by S. ERNEST SANFORD

Every fall, there is a sudden and apparently haphazard upsurge of spontaneous abortions in sow herds in temperate climates. In Ontario, these abortions start in September every year, increase in October, reach a peak in November and then decline thereafter.

These spurts of abortions are non-infectious (i.e. not PRRS or any other infectious disease). Most of the abortions occur in middle or late pregnancy, although it is possible that earlier pregnancies may have been terminated and fetuses reabsorbed or passed unnoticed. Sows that abort do not stop eating or have a fever, cough or show any sign of sickness. They just dump their pigs and press on as if nothing out of the ordinary had happened. The aborted piglets appear normal and, if it is a late-gestation abortion, some of the piglets may be alive, but premature, and usually unable to survive.

Post-mortems on aborted fetuses show no signs of disease. The lack of clinical and pathological findings suggests that this is a failure of pregnancy maintenance on the dam part rather than the result of any disease.

Although the burst of fall abortions occurs every year, the number of cases seen from year to year varies. In some years, only sporadic cases of abortion are observed or reported, whereas in other years abortion storms litter the countryside. Remember, these are non-infectious abortions and do not involve PRRS or any other disease agent. Thus, they are in addition to PRRS abortions, of which there is also an upsurge in the fall every year.

The number of abortions also varies from one herd to another. In some herds, up to 10 per cent of pregnant sows abort in peak months (September to December), while others have few or no abortions. The abortions are more likely to occur when there are marked fluctuations in temperature, especially when very low overnight temperatures (around or below freezing) follow mild or warm fall days (10-20ºC).

When I first started seeing and tracking these fall abortions nearly 30 years ago, the affected herds were what we then called medium- to large-size herds (150 to 500 sows). Over time, the larger herds, now more than 1000 sows, seem to have much less of a problem with these non-infectious fall abortions. Today, the small- to medium-sized herds, where there is less control over widely fluctuating temperatures, are more likely to be the ones experiencing this phenomenon.

Several factors have been identified as the cause of, or contributing to, fall abortions. The most common of these are the decrease in daylight hours, a drop-off in progesterone in the dam, and environmental temperature stressors.

Decreasing daylight hours. Our modern-day pig was domesticated from the European wild pig, which is a seasonal breeder. Estrous cycles in non-pregnant sows cease in July and restart in the fall (October to December). Declining daylight hours is probably the major thing terminating sexual activity. Factors that influence recommencement of the breeding season in the fall include availability of food supply and interactions with sexually mature boars.

Progesterone activity. In light of the above, we should expect that, in addition to sexual activity following the decrease in daylight from summer through to autumn, there would also be a similar decline in female sex hormonal levels accompanying this seasonal photoperiodic activity. And there is.

Progesterone is called "the pregnancy hormone." It is produced by the corpus luteum (CL) in the ovary. The CL is formed after an egg is expelled from the ovary. If the egg is fertilized and pregnancy occurs, the CL is maintained for the duration of the pregnancy. One of the functions of the CL is to produce progesterone, which is instrumental in maintaining pregnancy. Blood samples taken from sows in early and late pregnancy at different times of the year show a steep increase in progesterone levels in sows served in the fall and winter, reaching a zenith in the spring.

Spring, of course, would be the time when the wild sow would be delivering her piglets. In contrast, progesterone levels for sows that become pregnant in the spring and summer show only slight to negligible increases in progesterone levels between early and late pregnancy.

Environmental temperature stressors. So the stage is set. We have ancestrally programmed seasonal breeders, pregnant during the period of decreasing daylight and with low progesterone levels, whose ability to maintain pregnancy is likely on a "teeter-totter." Not a good combination. The "teeter-totter" can tip over and terminate the pregnancy if some unwanted stressors intervene.

Markedly fluctuating temperatures like those we experience in the mid-to-late fall can be one such stressor. It should also be noted that it is not unusual for the aborting sows to be at the end of a row closest to an exit door, in a row on an outside wall or in a cool air draught -- all meaning that these are sows more likely to be subjected to sudden temperature fluctuations.

Preventing the fall abortion syndrome is still handled on a mainly empirical basis. Here are some of the things that can be done in herds still experiencing fall abortions:

• Increase the amount of artificial lighting in the gestation area to provide 16-18 hours of light per day through the late summer and into the fall. The intensity of light should be 200 lux (about 18 foot candles), which is enough to read a newspaper. Provide extra heat (target 18-20ºC) during the risk period in the fall.

• Increase the plane of nutrition (energy intake) to the sow, without overfeeding (up to 2.5 kilograms), to compensate for maintenance of body heat in the colder periods.

Group housing may provide more opportunities for huddling and thus provide more communal heat.

It must be borne in mind, however that, unless the herd is experiencing the fall abortion problem, there is no need to take this kind of action. Working with your veterinarian would be the best way to sort out whether the fall abortion syndrome is occurring in your herd or if there is a real disease outbreak. BP

S. Ernest Sanford, DVM, Dip. Path., Diplomate ACVP, is a swine specialist with Boehringer Ingelheim Vetmedica (Canada) in Burlington. esanford@bur.boehringer-ingelheim.com

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Better Pork - October 2005

Public support for pork research needed more than ever

Today, such concerns as the environment, animal welfare, food quality and safety and disease prevention are driving research. And public funding is indispensable

by JIM DALRYMPLE

In Canada, and Ontario in particular, there have been dramatic changes and cuts in public funding for swine research in recent years. In fact, in many countries, the pork industry has seen a steady decline in spending by governments on the resources needed to undertake research in most disciplines. Yet the opportunities for the pork industry are immense as world demand for pork, poultry and other meat products escalates.

Australia has recently expanded its funding with an infusion of $20 million Cdn to establish a new Co-operative Research Centre for pork production and product development. The intent is to enhance the international competitiveness of their pig industry. The Australian industry slaughters about 5.5 million pigs annually. Similarly the Danes, the Dutch and Canada's other competitors are rethinking the need for publicly supported research. At the same time, agribusiness and the industry itself recognize the need for research investment.

The challenges facing the pork industry are different from those experienced 30 years ago, when increased production was the main criterion for research spending. Today, such concerns as the environment, animal welfare, food quality and safety and disease prevention are driving research. Many of our long-established facilities are not well equipped to research these new needs. For example, the opportunity to use animal wastes, both manure and carcasses, as a bio-fuel needs to be analyzed from many viewpoints, such as economics, health and the environment.

However, some partners in the pork industry have increased their research commitment. The Animal Health Industry (AHI) in the United States, for example, is investing more dollars in research. It spent $556 million in 2004 in the animal field to research and develop new products and to ensure the safety and effectiveness of existing ones. Its president affirms that "keeping animals healthy is important to keeping people healthy, and strong research and development programs are necessary to maintain a supply of new and innovative animal health products." This is evident with the viruses that have been seen in Asia in recent months.

The general public sometime questions the merits of this research, suggesting that animal health companies have dubious reasons for undertaking research. The cost of research is immense and the time and commitment to take research from initial development to final regulatory approval and subsequent application on farms is staggering. Public funds for animal health maintenance are critical.

There are many research initiatives that need to be carried out with public funds. One area is food safety research. Commitment to, and research in, food safety is on the decline in many parts of the world. According to U.S. university researchers, the ever-present threats to the food supply posed by disease, spoilage and the spectre of bio-terrorism need increased attention. Alternatives to such things as sow stalls and farrowing crates should also be the responsibility of all taxpayers.

The pork industry throughout the world continues to increase its support for research and education. Ontario pork producers identify and implement research initiatives in all phases of pork production through a check-off per pig marketed and with input from a producer research committee, the Agricultural Research Institute of Ontario and a multi-stakeholder Ontario Pork Research and Services Committee.

In 2005, the National Pork Council in the United States again identified key research needs in the following categories:

• Enhanced environmental responsibility in pork production;

• Ensuring production of safe, high-quality, nutritious pork;

• Safeguarding swine health and assuring swine welfare;

• Strengthening the profitability and global competitiveness of the pork industry.

In 2005, the Council awarded one of their key projects on animal welfare to the University of Guelph, indicating close co-operation between U.S. and Canadian industries. This study will look at how drinking behaviour influences feed intake and the development of behaviour problems in newly weaned pigs.

Ontario's research priorities are much the same as those of the United States:

1. The environment
2. Food safety
3. Animal welfare
4. Herd health
5. Nutrition
6. New products and technology
7. Pork product quality
8. Reproduction

There are also concerns about possible antibiotic resistance when products used in animal agriculture are also used in treating human health. Critics of pork production, and animal agriculture in general, say the overuse and misuse of antibiotics jeopardizes public health. This has not been substantiated and publicly funded research is needed to look into this. In recent years, the use of antimicrobials in Ontario and Canada has decreased.

Odour solutions, manure management and biogas production are other areas of research needing increased effort. These benefit society as a whole and should also be publicly funded. Continued research on biosecurity, genetic resistance to disease, animal identification and traceability are all designed to respond to consumer concerns.

Producers and their industry partners continue to fund research into artificial insemination, embryo transfer technologies that can improve animal health, product quality and profitability.

As well as research initiatives, educational programs similar to that at the Prairie Swine Centre in Saskatoon showing modern production technology would be beneficial. Almost 97 per cent of the public do not understand or appreciate the benefits of current production practices. BP


J.R. (Jim) Dalrymple P.Ag CAC is a former Ontario government swine specialist and owner of Livestock Technology Services in Brighton.

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Better Pork - October 2005

Wheat screenings prove good energy source for growing-finishing pigs

Recent research suggests that wheat screenings can be fed at levels as high as 72 per cent with no negative effects

by JANICE MURPHY

Wheat is one of the world's most important cereal grain crops. According to the U.N. Food and Agriculture Organization (FAO), worldwide production of wheat exceeded 600 million tonnes in 2004.

Wheat intended for human use or as animal feed is usually run through a series of blowers and shaking screens, which separate particles on the basis of density and size. The contaminants removed during this process are known as wheat screenings and usually consist of broken and shrunken wheat kernels, oil seeds, weed seeds and the like.

The nutritional value of wheat screenings is based on their botanical composition. In theory, shrunken and broken wheat kernels should be similar in nutritional value to wheat. But while weed seeds may have nutritional value, they could be a source of anti-nutritional factors that may interfere with pig performance. It has been some time since the nutritional value of Canadian wheat screenings has been evaluated, but recent research by Dr. Phil Thacker Prairie Swine Centre, in Saskatchewan has investigated the feeding value of this feed ingredient for growing-finishing pigs.

The chemical and botanical compositions of the number 1 wheat screenings used in the experiment are outlined in Table 1. In order to be classified as number 1 wheat screenings according to Canadian Grain Commission guidelines, the screenings must contain at least 35 per cent shrunken or broken wheat and no more than eight per cent wild oats and six per cent small weed seeds (such as canola, rapeseed, wild and domestic mustard seed).

Table 1. Chemical analysis and botanical composition of number 1 wheat screenings.
Chemical analysis (per cent as fed)
Moisture	12.29
Crude protein	13.27
Ether extract	3.08
Acid detergent fibre	4.62
Ash	1.82
Botanical composition (per cent as fed)
Broken wheat	77.14
Whole wheat	11.45
Wild buckwheat	6.70
Canola seed	2.80
Cleavers, wild oats, hemp nettle, canarygrass, cow cockle, flax, sweet clover, Russian thistle, brown mustard, and other seeds	1.91

Botanical analysis showed that the number 1 wheat screenings contained more than 88 per cent whole or cracked wheat, with the most prevalent weed seeds being wild buckwheat and canola seed. According to Dr. Thacker, these values differ dramatically from earlier research, which showed that wheat made up approximately 70 per cent of the screenings.

In the earlier samples, the predominant weed seeds varied from wild buckwheat (25.9 per cent) in one to wild buckwheat (4-12 per cent) and canola seed (5-11 per cent) in another. It is uncertain whether the differences between the botanical composition of modern screenings and those evaluated a number of years ago reflect changes in agronomic practices (such as reduction in summer fallowing and changes in available herbicides) or changes made to the cleaning process itself.

In the experiment, 40 crossbred pigs weighing an average of 19.7 kilograms were assigned on the basis of sex, weight and litter to one of five dietary treatments. The wheat screenings were included at levels of 0, 18, 36, 54 and 72 per cent in the grower diet (19.7 to 64.2 kilograms) and 0, 20.5, 41, 61.5 and 82 per cent in the finisher diet (64.2 to 105.1 kilograms). The experimental diets were barley-soybean meal rations with the wheat screenings typically added at the expense of barley.

The diets were formulated based on the assumption that the digestible energy (DE) for wheat screenings was slightly lower than barley, due to the presence of the lower energy weed seeds, and tallow was added to make up the difference. However, in reality, because the level of weed seed contamination was quite low, a DE value closer to wheat would appear to have been reasonable for wheat screenings in this case. Throughout the growing-finishing period, individual body weight, feed consumption and feed conversion were recorded weekly. Pigs were slaughtered at a commercial abattoir at an average weight of 105.1 kilograms and standard carcass measurements were recorded.

Pig performance during the experiment is shown in Table 2. Feed intake decreased in a linear fashion, while feed conversion improved linearly with increasing levels of wheat screenings.

Dr. Thacker offers two explanations for the reduction in feed intake with increasing levels of inclusion. It may be due to the presence of weed seeds, such as wild buckwheat, in the screenings, which have been reported to have a relatively low palatability. Or it may be explained by the higher energy content of the wheat screenings, since pigs are known to compensate for increases in the energy density of the diet by decreasing feed intake.

Regardless of the reason, over the course of the experiment, pigs grew at the same rate, no matter what the level of wheat screenings in the diet.

Table 2. Performance of growing-finishing pigs fed graded levels of number 1 wheat screenings.
	Level of wheat screenings (per cent)
Grower period	0	18	36	54	72
Finisher period	0	20.5	41	61.5	82
	Overall experiment (19.7-105.1 kg)
Daily gain (kg)	0.92	0.91	0.90	0.91	0.92
Daily intake (kg)	2.36	2.25	2.24	2.15	2.17
Feed conversion (kg/kg)	2.59	2.51	2.50	2.37	2.36

Table 3 shows that there were no significant effects on any carcass trait as a result of feeding wheat screenings, including dressing percentage, carcass value index, lean yield, loin fat or loin lean. Realistically, there is very little literature for comparison with the current slaughter data, although these results are similar to those of researchers in North Dakota.

Table 3. Carcass traits of growing-finishing pigs fed graded levels of number 1 wheat screenings.
	Level of wheat screenings (per cent)
Grower period	0	18	36	54	72
Finisher period	0	20.5	41	61.5	82
	Carcass trait
Slaughter weight (kg)	105.9	105.2	104.9	104.6	106.4
Carcass weight (kg)	82.5	82.0	81.8	83.3	83.9
Dressing per cent (per cent)	77.9	77.9	78.0	79.6	78.9
Carcass index	106.7	106.4	110.4	106.9	107.0
Lean yield (per cent)	58.9	58.9	60.1	58.9	58.3
Loin fat (mm)	21.9	21.9	18.7	22.0	23.3
Loin lean (mm)	53.6	57.3	54.7	56.4	55.5

This experiment suggests that number 1 wheat screenings can be successfully used as an energy source for growing-finishing diets and can be fed at levels as high as 72 per cent of the diet with no negative effects on pig performance or carcass quality.

However, it is important to note that if the level or type of weed seeds contaminating the screenings change appreciably from those reported in the current research, then it may be necessary to re-evaluate the inclusion level of wheat screenings in the diet. BP

References:
Anonymous, 2004. Official Grain Grading Guide -- Screenings. Canadian Grain Commission. August 1, 2004. Thacker, P.A. 2004. Performance of growing-finishing pigs fed barley-based diets containing graded levels of number 1 wheat screenings. Can. J. Anim. Sci. 84:403-409.

Janice Murphy is swine nutritionist with the Ontario Ministry of Agriculture and Food in Fergus. E-mail janice.murphy@omaf.gov.on.ca

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Better Pork - October 2005

What you can do to avoid heat stress and power loss

Pig performance will suffer under high temperature conditions. But there are things you can do to reduce the stress and avoid power-failure disasters

by RON MacDONALD

Every summer, Ontario has at least one hot humid spell when the humidex exceeds 40^oC for several days. During these times, animal stress is very high, particularly for groups that are at the end of a growth cycle and occupy maximum space density. The stress is further compounded by factors such as poor inlet layout/capacity, inadequate fan capacity, improperly set controls, sun hitting walls and roofs and, worst of all, power failure.

This summer so far has been the hottest on record. If you believe this trend will continue, you should be considering steps to provide a more comfortable hot weather environment for your pigs.

Pig performance will suffer under high temperature conditions. For Woodstock, average 24-hour temperature exceeds 88^oF at least 21 days each summer. This means that the average indoor temperature could be up to 93^oF on those days. Each facet of the production cycle has its own special needs and systems to overcome excess heat problems.

Farrowing room

Traditional drops in farrowing rates occur in the fall due to excess heat in the summer. Install drip nozzles or snout cooling for farrowing pigs. Put a thermostat on heat lamps or pads to turn them off when room temperature exceeds 80-85^oF.

Breeding room

Breeding pigs will not perform at the same level if heat problems are present. Install evaporative cooling pads to reduce actual room temperatures by 10-15^oF (5-8^oF).

Grower/finisher rooms

Supplemental cooling greatly benefits grower-finisher hogs. Grow-finish pigs reduce feed intake by 0.92 per cent for every 1^oF rise in effective environmental temperature (EET) above 70^oF. On a day with an average inside temperature of 93^oF, when not using supplemental cooling, pigs will reduce feed intake (FI) by 21 per cent.

The effective use of stirring fans and sprinklers together can provide as much as 25^oF reduction in pigs' EET. Sprinklers reduce EET by 8-10^oF and stirring fans reduce EET 15-18^oF. Spray cooling is the minimum component required. Additional benefits can be had from air inlets that ¡°down draft¡±' into the sleeping quarters during extreme heat or the use of variable speed, high-output stirring fans (common in poultry barns and green houses). It is critical to ensure that the entire cooling and ventilation system is well designed and controlled. Health problems can emerge quickly if cooling occurs during cooler weather.

Nursery rooms

In these rooms, adequate ventilation and a well laid out inlet system are necessary. High levels of ventilation should be avoided during hot weather when pigs are less than 20 kilograms. A "hot draft" to us can mean a "chilling draft" to newly weaned pigs, resulting in health problems.

The worst calamity causing heat stress is power failure in fan-ventilated buildings. This is compounded by self-adjusting air inlets which close tight when fans turn off. Many producers have opted for back-up generators, either tractor PTO driven or stand-alone. Regardless of which method is chosen, the following points need to be considered:

• Be sure you have a disconnect to isolate your farm from the Hydro One Networks (HON) grid. Your generator could make a nearby downed line live and a linesman could try to pick it up, so receiving a harmful or perhaps fatal shock.

• Have a system in place where someone is available 24 hours a day to connect a PTO generator. Check it at least six times per year and record the results.

• Be sure the generator can handle the loads that may be running, particularly for start-up.

• Install a reliable alarm system with an appropriate signal, such as an telephone auto-dialler or audible alarm.

• Check with your insurance company to see if it offers discounts it you have an alarm system and generator.

• Have a plan to save as many animals as possible if you are without power.

Following these recommendations can save thousands of dollars and eliminate needless losses. Costs for the various options are surprisingly low after the value of reduced performance and losses is factored in.BP


Ron MacDonald, P.Eng., is an agricultural engineer with Agviro Inc. in Guelph.

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Better Pork - October 2005

Better eating can lead the way to reduced health costs and benefit our local agriculture

If consumers spent more but better on food, it could make them healthier and encourage producers to develop even more nutritious products

by JIM DALRYMPLE

A recent two-day forum in Toronto highlighted the provincial government's commitment to reducing health costs and its concerns about increasing obesity among Canadians and the role our food we can play in maintaining a healthier population.

Entitled "Food - A Healthy Value Proposition," the program was a joint effort of the Ontario Ministry of Agriculture and Food, MaRS Landing and Ontario Agri-Food Technologies.

In Ontario, the proportion of government expenditures going to the Ministry of Health and Long-Term Care has escalated from under 30 per cent to more than 40 per cent over the past 10 to 15 years. Yet this increasing proportion of provincial revenues going to health care appears to have brought with it no corresponding reduction in disease or in health costs. At the same time, obesity has increased alarmingly in both young and older Ontarians.

Research scientists, technology transfer specialists, food manufacturers, retailers and farmers have made tremendous strides in providing consumers with more healthful and nutritious products. Meanwhile, over the past 40 to 50 years, consumer spending on food has dropped from more than 20 per cent of disposable incomes to under 10 per cent today, allowing us to allocate more dollars to new cars, larger homes, cottages and other non-essentials. Is it time to rethink what share of daily spending goes on food and provide a larger share of the food dollar to farmers to continue to provide highly nutritious products for all Ontarians?

Product development in fruits, vegetables, dairy and meat is enabling consumers to improve their lifestyle by choosing healthier portions and products. Consider:

• Through improved animal breeding, feeding and management, Ontario's pork producers have markedly increased the lean content of pork and reduced fat.

• A wide variety of dairy products -- skim milk, two percent and DHA-enhanced milk, goat products, low-fat cheese and yogurt -- are now available, offering clear nutritional benefits.

• With the support of agribusiness and research scientists, farmers have developed soybeans, canola products and a multitude of food items superior to those that our ancestors had to choose from.

• A new Harvard University study has found that dairy intake may reduce the risk of type 2 diabetes in men. After adjusting for other possible factors such as body mass, physical activity and other dietary factors, those who consume the highest amount of dairy products were 23 percent less likely to have type 2 diabetes than those with lower diary intake.

• The addition of whey to a meal may help diabetics improve their blood sugar control, according to current Swedish research.

• The recommended intake of nutritious fruits and vegetables is better understood today and is contributing to healthier diets.

Most people in Ontario could benefit from a greater awareness of the important benefits of foods from each of the four major food groups -- grains, vegetables, fruit, and milk and meat products. Yet how many of us can actually name them?

A 2001 report, entitled "Food Habits of Canadians," indicated that about 45 percent of adult women and 25 percent of adult men eat fewer than the minimum recommended daily servings of meat and protein alternatives. Knowledge of fat and sugar contents, vitamin and mineral levels of foods and intake requirements is clearly beneficial in reducing health problems. Yet all too many people rely daily on numerous pills to meet what they consider their daily vitamin, mineral and other needs. They have little knowledge of what they contain and what interactions may occur between them and other medications and health food products.

Food Guides, developed by governments and health specialists, and doctors can help consumers, young and old, in determining the correct diet. And a commitment by consumers to spending 12 to 15 per cent of their disposable income on food (up from the current 10) would further encourage producers to continue to develop new food products with specific health benefits.

New technologies, neutraceuticals, even genetically modified foods offer the possibility of reducing the escalating health costs now faced by all governments. The much- maligned pesticides and herbicides, which help insure safe, high-quality products, also offer the opportunity to improved health. Continued research to develop new pesticides is important, as is an increased commitment from governments to agriculture and food research, production and food education. An increase in government spending on agriculture and food could well reduce the long-term need for spending on hospitals, doctors and health care professionals by 10 to 20 percent in the future.

Consumer education needs to be improved to convince everyone about the merits of eating wisely. Coupled with this is the need to increase physical activity and lessen our addiction to television, computers and video games. The food industry may well hold the key to battling obesity and lowered health spending. Eating patterns, dietary intake and exercise can all make a dramatic difference in the cost of health treatment.

Research continues to refine daily nutrient requirements and food producers are improving foods to meet many diet-related, as outlined below.

Health consequences of inadequate intake of key essential elements
NUTRIENT	IMPORTANCE	CONSEQUENCES
Iron and zinc	Immunity	Lower resistance to infections
Calcium and vitamin D	Skeletal health	Poor bone health Increased fractures
B vitamins	metabolism	Many health problems

Food safety has become part of our everyday vocabulary. The food supply, particularly in Ontario, Canada and North America as a whole, is superior to anywhere in the world. Greater use of locally produced foods is a start in reducing health costs. Similarly, an increased expenditure on food by consumers and research on the production of that food can only help our battle to reduce long-term spending on health care. BP

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