xvi REFORMS IN CONDITIONS OF SUPPLY 275 



placed on opposite sides of the cowshed, about 5^ to 6 feet 

 above the ground. Inlet ventilation apertures near the ground 

 are not satisfactory. The outlet ventilators are placed at or 

 near the ridge of the roof. A continuous louvre running 

 almost the whole length of the roof is sometimes put in, or 

 one or more separate louvre openings, or openings with cowls. 

 All these forms may be quite satisfactory. 



The cowkeeper not infrequently objects to adequate venti- 

 lation, because, on the one hand, he declares that the sheds 

 being colder, the cows produce less milk, while, on the other 

 hand, he believes the animals are likely to be chilled and 

 illness result. Exact experiments do not bear out the former 

 supposition. For example, John Speir l concluded from a 

 careful series of experiments that as much milk was pro- 

 duced by the cows in freely ventilated sheds as in those less 

 ventilated and warmer. 



These experiments were repeated by Lauder and Fagan 2 

 in 1909-10. Two equal groups of cows as similar as 

 possible in respect of age, yield, quality of milk, and period 

 of lactation were selected. The one group was kept in one 

 part of the byre which was freely ventilated even in the 

 coldest weather, and the other in the other part of the 

 byre in which the ventilation was greatly restricted, so as to 

 keep the temperature as nearly as possible 10 degrees higher 

 than in the cold end. The average weekly temperature in 

 the cold byre varied from 43 to 55 F., the average tempera- 

 ture being 50*5 F. The results showed that the average 

 yield per cow per day in the cold byre was 27'54 lb., and in 

 the warm byre 2*7-14 lb. ; the average percentages of fat were 

 3'74 and 3'7 respectively. These results were confirmed at 

 other centres. The authors concluded that byres may be freely 

 ventilated even in very cold weather without impairing either 

 the yield or the quality of the milk. 



A herd of cows in Shropshire kept under open-air conditions 

 produced as much milk as a similar herd kept under warm- 

 shed conditions. The experiment was continued for four years 



The other contention is probably the exact opposite to the 

 truth. The cow is an adaptable animal, and if acclimatised 



1 Trans, of the Highland and Agricultural Society of Scotland, 1908. 

 2 Jo-urn, of Meat and Milk Hygiene, 1911, vol. i. p. 142. 



