The Honorable H. Q. Sibley, D. V. M. 

Executive Director 

Opinion No. H- 195 

Texas Animal Health Commission 

1020 Sam Houston State Office Bldg. 

Austin, Texas 78701 

Re: The authority of the 

Texas Animal Health 

Commission to prohibit 

the admission of Mexican 

cattle. into designated 

Tick Eradication Areas. 

Dear Mr. Sibley: 

You have asked whether the Texas Animal Health Commission has the 

authority under Vernon’s Texas Penal Code, Article 1525c, or any other 

statute to forbid the introduction of legally imported Mexican cattle into 

designated tick eradication areas of Texas. 

You have informed us that the Commission has reason to believe that 

Mexican cattle have developed an immunity to “Texas fever” or “splenetic 

fever, ” the disease carried by the fever tick. Even though these cattle 

have been rid of any ticks and show no ill effects they may carry the latent 

disease in their bloodstreams. ff one later becomes a host to a fever tick, 

the tick could transmit the disease from the immune Mexican cow to nonimmune Texas cattle. 

Works on veterinary medicine inform us that historically~“Texas fever” 

has been one of the most destructive diseases among cattle. At one time 

practically all cattle in the southern United States were affected by the disease. 

Pioneering research led to the discovery that the disease was caus.ed by the 

development and activity of minute protoplasmic parasites, Piroplasma 

bigemina, in the blood streams of cattle. For the first time it was discovered 

that a disease was transmitted from one animal to another by an intermediate 

host or carrier, in this case the Texas fever tick or cattle fever tick, 

p. 913 
. 

The Honorable H. Q. Sibley, page 2 (H-195) 

Margaropus annul&us. Since it appears the fever tick is the only means by 

which the disease is naturally transmitted from .snimal to animal, eradication 

of the fever carrying ticks will cause the disease to disappear, In 1906 the 

United States began a campaign to eliminate the fever tick, and now tbe 

spread of the disease has been virtually eliminated in this nation. Only a 

few counties along the Rio Grande are under permanent quarantine because 

of the presence of ticks. See generally U. S. Dept. of Agriculture, Animal 

Diseases, pp. 310-313 (1956); Dykstra, Animal Sanitation and Disease Control, 

pp. 747-749 (1961). 

The legislative machinery by which Texas has combatted this disease 

is Article 1525~. the Tick Eradication Law. It provides methods for eradicating ticks and thus controlling the disease. The proposal about which you 

inquire would provide another means of controlling the fever. Instead of 

concentrating all efforts on eliminating the carrier, the Commission is 

considering measures to prevent the introduction af~.sources of the disease 

in areas where the carrier tick may exist. You have informed us that testing 

cattle to determine whether they carry the disease is prohibitively expensive, 

and your inquiry involves a proposal to prevent the introduction of all Mexican 

cattle into a designated Tick Eradication Area. Although the Commission 

has no present evidence that Mexican cattle have caused infection of Texas 

cattle by their introduction into Tick Eradication Areas in this state, you 

inform us that it is likely that as many as one-half of Mexican cattle crossing 

from Mexico into the United States could be carriers of the disease. 

The Legislature has enacted a series of statutes to combat this and 

other diseases of animals under the provision of the constitution permitting 

the passage of laws for the regulation of livestock and the protection of 

stock raisers. Texas Constitution, Article 16, $ 23. One of the laws 

enacted pursuant to the constitutional provision is Article 1525c, Vernon’s 

Texas Penal Code, the Tick Eradication Law, (to be republished as Article 

7014g-1, Vernon’s Texas Civil Statutes). Section 1 of that article provides 

in part: 

“It shall be the duty of the [Texas Animal 

Health Commission]. . . to eradicate the fevercarrying tick (Margaropus Annulatus) in the St&e 

p. 914 
The Honorable H. G. Sibley, page 3 (H-195) 

of Texas and to protect all lands, territory, 

premises, cattle, horses, mules, jacks and 

jennets in the State of Texas from said tick and 

exposure thereto, under the provisions of this 

Act. Said Commission shall adopt necessary rules 

and regulations, to be proclaimed by the Governor 

of the State of Texas, for carrying out the provisions 

of this Act. ” 

Article 1525b of the Penal Code (to be republished as Article 7014f-1, Vernon’s 

Texas Civil Statutes) involves the control of disease among live stock, Section 

1 of that article provides in part: 

“It shall be the duty of the [Texas Animal 

Health Commission]. . . to protect all cattle, 

horses, mules, asses, sheep, goats, hogs, and 

other live stock, and all domestic animals and 

domestic fowls of this State from infection, 

contagion or exposure to the infectious, contagious 

and communicable diseases enumerated in this 

Section . . . and other similar and dissimilar 

contagious and infectious diseases of live stock 

recognized by the veterinary profession as 

infectious or contagious. . . . Said Commission 

may at its discretion whenever it is deemed~ 

necessary or advisable also to engage in the 

eradication and control of any disease of any 

kind or character that affects animals, live 

stock, fowls or canines regardless of whether 

said diseases are infectious, contagious or 

communicable and may establish necessary 

quarantines for said purpose. . . . . Said Commission shall adopt rules and regulations to be 

proclaimed by the Governor of the State of Texas 

for the purpose of carrying out and enforcing 

the provisions of this Act. . . . No provision 

of this Act shall relate to tick eradication; ” 

(emphasis added). 

p. 915 
The Honorable H. Q.. Sibley, page 4 (H-195) 

The proposal you suggest is designed to p.revent the introduction and 

spread of “Texas fever” in this state. Technically it is not a tick eradication 

measure. Instead, it is designed to prevent disease. We find it unnecessary, 

therefore, to determine whether Article 1525c, the Tick Eradication Law, 

provides the authority for the adoption of the measures you suggest, since 

‘the proposals may be authorized underArticle~l525b’s grant of authority to 

the Commission to eradicate and control “any disease of any kind or character 

that affects animals”. 

The Commission’s proposed action is clearly within the police power 

of the state. Rasmussen v. Idaho, 181 U. S. 198 (1901); Smith v. St. Louis 

& Southwestern Railway Co. , 181 U. S. 248 (1901); Armstrong v.’ Whitten, 

41 F; 2d 241 (S. D. Tex. 1930). 

It is axiomatic that a state regulation cannot stand if it conflicts with 

a federal statute or regulation. Article 6, clauae.2, of the United States 

Constitution, the Supremacy Clause. Also, the state may not regulate 

commerce inan area in which the federal government has pre~empted the 

regulatory field. Article 1, $ 8, clause 3 of the United States Constitution, 

the Commerce Clause. In Rice v, Santa Fe Elevator Corp. ,, 331 U.S. 218, 

230 (1947), the Court said: 

“The question in each case is what the purpose 

of Congress was. 

‘1. . . Such a purpose may be evidenced in several 

ways. The scheme of federal regulation may be so 

pervasive as to make reasonable the inference that 

Congress left no room for the States to supplement 

it. . . . Or the Act of Congress may touch a field 

in which the federal interest is so dominant that the 

federal system will be assumed to preclude enforcement of state laws on the same subject. . . . Likewise, the object sought to be obtained by the federal 

law and the character of obligations imposed by it 

may reveal the same purpose. . . . Or the state 

policy may produce a result inconsistent with the 

objective of the federal statitte. I’ 

pe 916 
The Honorable H. Q.. Sibley; page 5.~ ~(H-195) : 

After carefully examining the federal regulatory scheme it is our 

conclusion that Congress did not intend to preempt the field. See, Savage 

v. Jones, 225 U.S. ~501 (1912); Reid ‘v. Colorado, 187 U.S. 137 (1902); 

Missouri, Kansas & Texas Railway Co. . v. Haber- :169 U. S. 613 (1898). 

Indeed, the Congress and the Secretary of Agriculture specifically contemplate concurrent state regulation. 21 U.S. C. $114, 9 C. F.. R. $ 72-10. 

21 U. S. C. § 104, authorizes the Secretary of Agriculture to permit 

the entry of certain Mexican’cattle into the State of Texas. As it is our 

understanding that the proposed regulation would merely prevent their 

entry’into designated Tick Eradication areas, we do not believe it would 

conflict with any’ specific ~federal statute or the general federal regulatory 

scheme. 

A state’s absolute quarantine against cattle from another state may 

be permissible under the-commerce clause. Smith v. St. ~Louis & Southwest 

Railway Co., supra. The test to be used in determining whether a state 

reeulation unduly affects interstate commerce is essentially a balancing 

test. It was recently articulated in Pike v. Bruce Church, *Inc. , 397 Ul S. 

137, 142 (1970) where the United States Supreme Court said: 

“Where the statute regulates even-handedly to 

effectuate a legitimate local public interest, and 

its effects on interstate commerce are only incidental, 

it will be upheld unless the burden imposed on such 

commerce is clearly excessive in relation to the 

putative local benefits. . . . If a legitimate local 

purpose is found, then the question becomes one 

of degree. And the extent of the burden that will 

be tolerated will of course depend on the nature of 

the local interest involved, and eon whether it could 

be promoted as well with a lesser impact on interstate 

activities. ” 

The validity of the proposed regulation would depend on its scope and 

its effectiveness in promoting the health of cattle in this state. The only 

regulation that. has been suggested to us is in a very general outline form, 

and without more specific information as to its scope, we are not able to 

p. 917 
. 

The Honorable H. Q.. Sibley. page 6 tH-195) 

render any jud.gment on its legal validity in respect to the commerce 

clause. The soundness of the veterinary theory on which it is based would 

be a relevant consideration in determining the regulation’s validity, but 

we are not equipped to make such factual determinations. We can say, 

however, that regulations of the type you. have outlined would not necessarily 

be precluded by the federal government’s power over interstate and foreign 

commerce. 

SUMMARY 

The Texas Animal Health Commission has the authority 

to prohibit the admission of Mexican cattle into designated Tick 

Eradication Areas in sn attempt to prevent the introduction and 

spread of splenetic or Texas fever. Such a regulation would not 

necessarily be precluded by the federal government’s power over 

commerce. 

// 

Attorney General of Texas 

A 

DAVID M. KENDALL, Chairman 

Opinion Committee 

p. 918