1. 1. a) The Canadian dairy industry is a key contributor to the economy, generating $5.2 billion in net farm receipts during the year 2007 by producing 80.8 million hectolitres of milk. The main breeds of dairy cows are Holstein (more than 93%), Ayrshire, Jersey, Brown Swiss, Canadienne, Guernsey, and Milking Shorthorn. Data in Table 1 reveals that the number of dairy farms in Canada has declined to a two third during the past decade. In the same period, the number of lactating cows also witnessed a steady drop (one third) from 1.16 to 0.98 millions. The average milk production of a Canadian Holstein registered a steady improvement (7%) from 30.04 to 32.25 kg per day. Year19992000200120022003200420052006200720082009Dairy farms2062419411186731793116970162241522214660140361358713214Dairy cows x 1000 heads1156.71103.41091.01083.91065.51054.91041.41019.11004.8988.5978.4Average daily milk production (kg) of Holsteins30.0430.6630.9531.8631.8731.6731.5531.7331.9132.25- Table 1. Trends in the number of farms, dairy cattle and milk production over the past decade in Canada. Since 1980, the average herd size and milk production per cow have increased dramatically. There has been a considerable advance in the arena of disease management, with a decrease in the incidence of milk fever, respiratory disease in adults, contagious mastitis and clinical parasitism. There has also been improved protection, through vaccination against coliform mastitis and bovine viral diarrhoea. Mastitis control has been ensured through pre and post-milking teat disinfection and by ensuring long-acting antibiotic therapy at drying-off. Improved mastitis control resulted in lower bacterial and somatic cell counts from milk especially in many provinces. On a yearly basis, 31% of lactating cows in Canada experience an episode of clinical mastitis. Though the dairy cows are productive for as high as 10 or more lactations, because of the chances of problems which may lead to a cow being culled being high; the average herd life of Holsteins today is on an average 3.4 lactations. This definitely requires more expensive herd replacements. While some cows may live considerably longer, the normal productive life of a Holstein in North America is six years. b) The general farm size in Canada increased over the past decade and farms have become more efficient in operation. The average production per farm has increased significantly, by 62%, since 1999. An average dairy farm has an area of 163 hectares (ha), with an average herd size of about 66-72 cows. The average American herd is much higher with over one hundred cows per farm. This varies from an average of 800 cows in California to under 80 in the North East states. In USA, less than 30 % of the farms are smaller than 20 ha. Average farm size is 80 ha. In Minnesota, the average herd size is 77. California has 1,100 farms with 500 or more cows, compared to Minnesota’s 60. Most farms in Norway are between 5 and 20 ha. In the early 1990's, the average farm size in Norway was 11 hectares (ha) which at present is 13. The number of dairy cows per farm in Norway is just 13, which is much smaller than other countries. In Denmark, in 1985 there were over 30,000 dairy farms and in 2006 this had reduced to just over 5,000. The average farm size is 50- 60 ha. The average herd size is now 105 cows and has been doubling every 5-6 years. c) Dairy cows live in barns that use one of two systems: free-stall or tie-stall barns. The traditional tie-stall barn provides each cow, her own stall with bedding and free access to food and water in front of her in a manger. She is milked in her stall and can be let out to pasture. Tie-stalls are the most common ones in Canada. Each cow has a separate stall that permits individual attention during feeding, grooming and milking. Free-stalls are the most popular for a herd size of 50 or more. The resting area is divided into individual stalls without ties, paved alleys are provided and they need much less bedding. Cow comfort and ergonomic design continue to be the focus of dairy barn construction. With an increasing herd size in trend, in the future the dairy industry appears to be for free-stall housing. d) Intensive dairy operations routinely adopt the free stall system to improve animal welfare and also to reduce labour. The cow benefits from the freedom of movement and exercise she gets. As long as feed, water, and space for eating, standing, walking, and resting are readily available, the competition for these resources will be kept to a minimum. Care should be taken to see that the stalls are comfortable, footing is secure and cleanliness is maintained. “Free stall systems are not an improvement in animal welfare if cow numbers exceed stalls by 15% and when the space is too small for the cows”. A recent study revealed that milk production was significantly lower, reproductive performance better and the incidence of ketosis and teat injuries lower in the free-stall compared to tie-stall herds. “In the free-stall group, the following improvisations had significant effects: warm over cold housing (lower milk production in cold housing), roughage feeding system (higher milk production with automatic feeding) and cubicle flooring (higher milk production and lower somatic cell counts with mattresses)”. Tied Stall Housing AdvantagesDisadvantagesCleaner cowsTying and untying is requiredIndividual attention for all animalsReduced opportunity for exerciseReadily mechanizedLabour intensive if not mechanizedComfortable for most choresUncomfortable to milkEconomicalGood for small herdsLess opportunity for movement, Poor animal welfareNot suitable for larger herds Free Stall Housing AdvantagesDisadvantagesEconomical operating costsExpensive construction costsReadily mechanizedLess individual attentionGreater freedom for movement, exercise, and more opportunity for social interactions.More competition if resources are not optimum, chances of injuries.Some flexibility in organizing different management-feeding groupsHigher density of stockingDirtier cows if improperly designed or operated leading to higher incidence of mastitis and foot lesions.Comparatively lower milk production.