The concentration of swine production. Effects on swine health, productivity, human health, and the environment.

The concern about environmental issues centering around CAFOs is appropriate. The veterinary profession can be an important force in meeting these challenges by broadening its scope of knowledge and practice into the broader environmental field. Although animal agriculture's contribution to environmental concerns is the focus of this article, it is only one of several sectors that contributes to environmental degradation. Crop production, as well as livestock production industries, contribute to pollution. Manufacturing industries, municipalities, private individuals, our consumptive lifestyles, and agriculture all contribute to the degradation of our environment. One must keep in mind the huge importance of our agricultural industry and not single it out to the detriment of its progress. We have an abundance of high-quality foods at the lowest cost to the individual of any industrialized nation. We export over 40 billion dollars in agricultural products yearly. Agriculture sustains our rural economies and provides opportunities for over 2 million private enterprises scattered across the country; however, there is a goal that we have a sustainable agriculture. A big part of that depends on development and enhancement of an agriculture that does not pollute, that sustains its farm operators and workers, and that does not make the area residents ill or degrade their quality of life; however, the current situation is not promising. Much remains to be learned about the actual acute and long-term health consequences of animal agricultural pollution. Many health concerns are speculative, even though based on sound facts. We know that many surface waters have excess N and P that leads to eutrophication and possibly enhanced growth of undesirable organisms such as Pfiesteria piscicida. We know that other animal pathogens, such as cryptosporidia, have caused large community outbreaks. There are other potential pathogens, such as Salmonella sp, for which we do not know the hazard. We know that our soils may become excessively laden with P, Cu, and Zn, which retard plant growth and create toxic conditions for grazing animals. There are concerns about air pollution. Odors have negative sensory and physical health consequences. H2S and dust may cause toxic effects on neighbors. NH3 vaporizing from manure sources may be carried with precipitation to cause eutrophication in lakes or altered ecosystems in natural areas. CH4 escaping from degrading manure contributes to greenhouse gases. Workers in confined livestock structures have high risk for a variety of chronic respiratory conditions. They also are at risk for acute poisoning from H2S in operations where liquid manure is stored in confined spaces. There have been numerous health complaints in recent years from community neighbors of large-scale livestock operations. One study showed adverse altered mood states, and another showed evidence of respiratory illness similar to what workers experience. Although it has not been possible to objectively measure conditions and know toxic levels of substances causing these illnesses, there are so-called extratoxic mechanisms, such as inherent aversion to putrefactive odors and exacerbation of preexisting conditions that lower the tolerance threshold. Environmental concerns regarding livestock production are not new. In the early and mid-1970s, there were many conferences and publications regarding odors and water contamination from livestock operations. Although most of what is known in this area has been known for 20 years, relatively little effective efforts have been made to correct the concerns. In fact, trends over this past decade have increased the concerns. This past decade has seen a tremendous acceleration in the concentration and consolidation of agriculture, capping a slow trend over the past 50 years toward larger, fewer, and more-specialized farms. This trend has gone against the old saying that "dilution is the solution to pollution.     

Influence of endogenous factors on the ash, calcium, magnesium, potassium, sodium, phosphorus, zinc, iron, copper and manganese contents in the bristles of pigs. 3. Influence of time of cutting on the mineral composition of the hair (boar bristles)]

The ash content and the content of Ca, Mg, K, and Na in the bristles of pigs is influenced by the age of the animal and by the season of the year. The peak concentrations of ash, Ca and Mg in the bristles of eight boars (cut every month) were found in June, shortly before the change in hair coat. (P less than 0.05-0.001). The concentrations of K and Na in the bristles deviated functionally from the change in the hair coat. In the first half of the year the bristles of the boars contained significantly more K and Na than in the second half. Values for the elements P, Zn, Fe, Cu, and Mn were subject to great variations through the year. These variations were found to be different with different animals. The influence of endogenic factors on the Mn content of the bristles was particularly striking, also in regard of the order of magnitude. The processes of Mn metabolism in the bristles are obviously still archaic in origin and would thus only allow to make comparison with other values of the mineral content of bristles at the very time of sampling. Differences in the P, Zn, Fe and Cu content of bristles in the different months were, in some instances, statistically significant although variations in the annual mean values were found to be relatively small.     

Effect of cambendazole on swine kidneyworm,Stephanurus dentatus

Two trials were conducted to determine the effect of cambendazole against natural infections of the swine kidneyworm, Stephanurus dentatus, in sows. In the first trial, nine sows were given a single dose of 20 mg cambendazole/kg body weight, in the feed, and eight sows were not treated. In the second trial, five sows were given 40 mg cambendazole/kg body weight and four were untreated. Urine volume, S. dentatus eggs per milliliter of urine, egg hatchability, and larval survival to the third stage were determined pre and post treatment. Adult kidneyworms were counted at necropsy, 14 days after treatments. Only a temporary decline in egg hatchability was observed on the day after treatment in each trial, and cambendazole was not found to be effective against adults of S. dentatus.     

Vitamin A requirement of growing swine. 1. Effect of vitamin A supply on growth of piglets and fattening swine

For the purpose of ascertaining the vitamin A requirement seven experiments with 303 pigs in the live weight range between 6.5 and 114 kg were made. In three experiments under in practice conditions we checked the standard vitamin A supplement to the mixed feed with 1,732 pigs (live weight range between 8.5 and 110 kg). The supplement to vitamin-A-free rations and to those poor in or free of carotene amounted to between 0 and 8,000 IU/kg feed. Above that, between 0 and 16 mg beta-carotene and 1,000 mg nitrite/kg feed were supplemented. As long as the vitamin A store in the liver during weaning amounted to greater than 50 IU and greater than 100 IU/g at the beginning of fattening, feed intake, live weight growth and feed expenditure were not influenced by the supplement of vitamin and provitamin resp. The supplement of 250 IU resulted in the same weight growth from weaning to the end of fattening as that of 4,000 IU. Nitrite supplement had a negative effect at 250 IU, at 500 IU vitamin A consumption and weight growth tended to be only insignificantly lower. The methaemoglobin content decreasing in the course of the experiment reflects the adaptation of the pigs to the nitrite load. The consumption and growth depression caused by vitamin A deficiency could be observed from the 7th week of the experiment when casein-swelling starch rations were fed, but from the 13th week of the experiment only when cereal-soybean oilmeal rations were fed. The weight of liver, spleen, kidneys, heart and brain was not influenced by vitamin A supply. The same applies to the body composition and retention with the exception of two deficiency piglets, which contained less fat in the empty body than the control animals.     

Vitamin A requirements of growing swine. 3. Effect of vitamin A supply on the state of health of piglets and fattening swine

Diseases and losses were registered in dependence on vitamin A supply with 2,035 pigs (6.5-114 kg live weight). The histologic examinations comprised various organs of 72 animals. The content of the main protein fractions as well as antibody titre after supplementing antigenes were determined in the serum of 104 animals. The feeding of a vitamin-A- and carotinefree casein-starch-respectively a Vitamin-A-free cereal-soybeanmeal-diet led to deficiency symptoms after 7-8 respectively 16-19 weeks of experiment particularly in the shape of nervous disturbances and voice affectations. Histologically a hyperplasia and a metaplasia of the epithelium of the big ducts in the salivory gland could be proved. The repletion of a part of the avitaminotic animals by means of oral (500 I.U./kg feed) and parenteral (500,000 to 1,000,000 I.U. i.m.) vitamin A administration is proof of a lack of vitamin A. Vitamin A and provitamin dosage did not influence diseases and losses with the exception of the occurrence of deficiency symptoms. The protein content of the serum as well as that of the globulin fractions alpha, beta, gamma did not change, the albumin content was lower in the groups without vitamin A (p greater than 0.05). Antibody titre against the lipopolysaccharide of salmonella dublin and human gamma globulin were diminished in piglets and fattening pigs fed vitamin A free (p less than 0.05). Taking the criterion of animal health, a vitamin A requirement higher than for growth (250 I.U./kg feed) cannot be derived.     

Effect of ascariasis and respiratory diseases on growth rates in swine.

Growth rates, measures of ascarid burden, and the levels of anteroventral pneumonia and atrophic rhinitis at slaughter were determined for 352 hogs born between March 8 and March 28, 1987 on 15 farms located in Prince Edward Island. Regression analyses were used to determine associations between average daily gain (ADG) and independent variables controlling for sex, farm, and litters nested within farm. The regression model accounted for 75.4% of the variation in ADG. The number of intestinal ascarids at slaughter did not affect ADG. However, the "life-time burden" (a composite measure based on fecal egg counts and duration of infection) was associated with ADG (p less than 0.05) in a quadratic manner. Although heavy ascarid burdens decreased the growth rate of swine, the magnitude of the effect was minimal. The maximum improvement one could expect from reducing the ascarid burden on heavily infected farms would be less than 1%. Severe atrophic rhinitis and the presence of anteroventral pneumonia each had a detrimental effect on ADG (p less than 0.001). The corresponding reductions in mean ADG were 7.7% and 2.8% respectively. There was significant interaction between the effects of atrophic rhinitis and anteroventral pneumonia on ADG (p less than 0.05). Hogs with both anteroventral pneumonia and severe atrophic rhinitis had a 17.6% lower ADG than hogs with neither disease. There is much greater potential for improvement in ADG through control of respiratory diseases than through control of ascariasis.     

Effect of various vaccination procedures on shedding, latency, and reactivation of attenuated and virulent pseudorabies virus in swine.

Various procedures of vaccination for pseudorabies were compared for their effects on shedding, latency, and reactivation of attenuated and virulent pseudorabies virus. The study included 6 groups: group 1 (10 swine neither vaccinated nor challenge-exposed), group 2 (20 swine not vaccinated, but challenge-exposed), and groups 3 through 6 (10 swine/group, all vaccinated and challenge-exposed). Swine were vaccinated with killed virus IM (group 3) or intranasally (group 4), or with live virus IM (group 5) or intranasally (group 6). The chronologic order of treatments was as follows: vaccination (week 0), challenge of immunity by oronasal exposure to virulent virus (week 4), biopsy of tonsillar tissue (week 12), treatment with dexamethasone in an attempt to reactivate latent virus (week 15), and necropsy (week 21). Vaccination IM with killed or live virus and vaccination intranasally with live virus mitigated clinical signs and markedly reduced the magnitude and duration of virus shedding after challenge exposure. Abatement of signs and shedding was most pronounced for swine that had been vaccinated intranasally with live virus. All swine, except 4 from group 2 and 1 from group 4, survived challenge exposure. Only vaccination intranasally with live virus was effective in reducing the magnitude and duration of virus shedding after virus reactivation. Vaccination intranasally with killed virus was without measurable effect on immunity. Of the 55 swine that survived challenge exposure, 54 were shown subsequently to have latent infections by use of dexamethasone-induced virus reactivation, and 53 were shown to have latent infections by use of polymerase chain reaction (PCR) with trigeminal ganglia specimens collected at necropsy. Fewer swine were identified by PCR as having latent infections when other tissues were examined; 20 were identified by testing specimens of olfactory bulbs, 4 by testing tonsil specimens collected at necropsy, and 4 by testing tonsillar biopsy specimens. Eighteen of the 20 specimens of olfactory bulbs and 3 of the 4 tonsil specimens collected at necropsy in which virus was detected by PCR were from swine without detectable virus-neutralizing antibody at the time of challenge exposure. One pig that had been vaccinated intranasally with live virus shed vaccine virus from the nose and virulent virus from the pharynx concurrently after dexamethasone treatment. Evaluation of both viral populations for unique strain characteristics failed to provide evidence of virus recombination.     

Vitamin A requirement of growing swine. 2. Effect of the vitamin A supply on the vitamin A concentrations in the liver and plasma of piglets and fattening swine

In 9 experiments the vitamin A content of the livers of 64 newborn (still births and deaths up to 48 h p.p.) and 69 weaned piglets, 122 growers and 110 fattening pigs was investigated after slaughtering or autopsy. Liver samples were taken from 78 growers by means of biopsy after latarotomy. A fluorometric analysis of the plasma vitamin A level was made. At the time of birth the vitamin A content of the piglet livers was less than 100 IU/g and did not show any differences between the experiments. At the time of weaning, however, the livers of piglets from large-scale production showed a three times higher content (175 IU/g liver) in comparison to those from traditional production. Highly significant linear relations were established between the vitamin A content of the feed and the liver. According to these, a liver content of vitamin A of approximately equal to 30 IU/g is ensured by approximately equal to 2,000 IU in weaning piglets and by approximately equal to 800 IU vitamin A/kg feed in fattening pigs. The vitamin A activity of the beta-carotene in weaners was ascertained as less than 100 IU/mg. The plasma vitamin A level indicated the vitamin A status only in the range of deficient supply. A different plasma content could not be detected between 1,000 and 4,000 IU vitamin A/kg feed. According to this, a semilogarithmic relation was calculated according to the model of a saturation curve between the vitamin A content of the plasma and the liver. The threshold value for the decrease of the plasma level under 45 IU vitamin A/dl is 35 IU/g liver. Due to the low definiteness measure (B = 0.52) the relation cannot be applied to the individual animal. A contamination of 1,000 mg nitrite/kg feed had a low, and in the course of the experiment decreasing, influence on the vitamin A content of plasma and liver.     

盐酸克林霉素对猪肺炎霉形体病的疗效试验

进行了克林霉素对猪肺炎霉形体病的疗效试验,并与卡那霉素、泰乐菌素、土霉素、恩诺沙星进行了比较。结果:盐酸克林霉素组的死亡率、有效率、治愈率和相对增重率分别为0、100%、96.67%和82.5%;卡那霉素组分别为6.67%、73.33%、67.67%和79.1%;泰乐菌素组分别为10%、60%、50%和65.4%;土霉素组分别为16.67%、63.33%、53.33%和76.7%;恩诺沙星组分别为0、80%、80%、78.2%。经统计学分析,盐酸克林霉素组和恩诺沙星组的死亡率明显低于感染对照组(P<0.01),治愈率、有效率显著高于感染对照组(P<0.01)。表明盐酸克林霉素对猪肺炎霉形体病的治疗有很好的疗效,在猪肺炎霉形体病防治中有很好的应用前景。     

Effect of fusaric acid on brain regional neurochemistry and vomiting behavior in swine.

Fusaric (5-butylpicolinic) acid is a phytotoxin produced especially by Fusarium moniliforme, a mold commonly found in Canadian-grown corn. Experiments were conducted to determine the effects of acute doses of fusaric acid on brain neurochemistry and behavior in swine. A total of 40 crossbred barrows (initial weight 10 kg) were orally dosed with 0 or 200 mg of fusaric acid/kg of BW and five animals from each treatment were killed 4.5, 9, 18, or 36 h after dosing. All brains were dissected, and concentrations of indoleamine and catecholamine neurotransmitters and metabolites were determined. Animals in the group killed 36 h after dosing were observed for behavioral changes. Vomiting was noted in 60% of the pigs dosed with fusaric acid. These pigs also seemed more lethargic than controls and appeared sedated. The major neurochemical changes due to exposure to fusaric acid were seen in the hypothalamus 18 h after dosing. Brain tryptophan, serotonin, and 5-hydroxyindoleacetic acid all tended to be elevated by the action of fusaric acid. Brain catecholamine concentrations were largely refractory to treatment. It was concluded that exposure to acute doses of fusaric acid can cause vomiting and neurochemical changes in swine. Fusaric acid may, therefore, be acting synergistically with trichothecene mycotoxins to cause vomiting and feed refusal in pigs consuming trichothecene-contaminated feedstuffs.     

叶酸对母猪产仔数的影响

叶酸即维生素 B11,它参与多种酶的活动 ,更重要的是与氨基酸和核苷酸的合成有关。多数研究结果表明 ,猪常用饲料的叶酸供给量 ,再加上肠道微生物合成的叶酸都可以满足各种猪的需求。但对于母猪补饲叶酸的效果尚存在争议。为了探讨叶酸对母猪繁殖力的影响 ,在漳州某猪场 ,用补饲的方法在断奶母猪的日粮中添加叶酸进行以下实验。1　材料与方法1 .1　实验猪　在本场选择长大二元杂交断奶母猪3 6头 ,按胎次品种随机分成对照组与实验组 ,每组1 8头。1 .2　日粮配制　含能量 70 5 k J,粗蛋白 1 5 .2 1 %,钙 0 .6 3 %,磷 0 .5 6 %,试验组在日粮中…