272 A TICK-RESISTANT COXDITION IN CATTLE. 



Jones, has pro\ eel successful, the animal becoming progress- 

 ively cleaner, while some cows, however, remained un- 

 affected ])y the vaccination. {See Vallonia line in genea- 

 logical tables). 



A ticky Jersey bull was vaccinated on March 23rd, 

 1916, from a glycerinated "culture"' {i.e., scraping). Six 

 weeks afterwards the first pustule appeared and the animal 

 gradually became resistant. He Avas carrying a feA\- odd 

 mature ticks when examined by us. 



We are indebted to Mr. Jones" kindness for the pedi- 

 grees quoted later on. 



While in the Crohamhurst district Ave were enabled by 

 the courtesy of Mr. Jones to inspect seA^eral other farms. 

 On April 7th, a visit Avas paid to Mr. Owen Jenner's farm, 

 a small but ricli one, being composed entirely of scrub land 

 carrying paspalum and cloAer. The coa\^ were in A'ery good 

 condition. The milking herd consisted of about 40 head, 

 the predominating breed being Shorthorn with an admixture 

 of Jersej^ Of the forty, fifteen were quite clean ; another 

 fifteen carried Aery light infestation, while the remainder 

 of the herd Avere heifers Avhich, though carrying more ticks, 

 could not be said to be badly infested. The bull had a 

 fair sprinkling of mature ticks, chiefly on the neck and 

 shoulders. He Avas very ticky last Aear. Mr. Jenner 

 considered the resistance became stronger as the beast 

 grew older. He had neA'^er practised A-accination, and could 

 only speak in a general Avay about hereditary transmission 

 of the peculiarity, never haAnng kept any records. He 

 was of the opinion that it may be transmitted but that there 

 was no regularity. He always had a few clean cows, but 

 never took much notice of them until some three or four 

 3^ears ago a number in some waj' became resistant ; this 

 condition has apparentl}'^ been spreading for now there are 

 very few animals that require washing. The young stock 

 Avere also lemarkably free from ticks. 



After leaving Mr. Jenner a visit Avas paid to the adjoin- 

 ing farm, the property of Moore Bros. The milking herd 

 consisted mainly of Jerseys. There Avere four cows Avhich 

 never needed Avashing, but with the exception of two or 

 three animals none of the herd became really badly infested. 



