A Total Merit Selection Index for Ontario Organic Dairy Farmers

Abstract

Organic standards require changes in management practices so that health, fertility, and overall fitness are more important than on conventional dairy farms and require different selection objectives. A survey involving 18 (40%) Ontario organic dairy farms was carried out to collect data on their production systems, breeding policies, and concerns. Compared with conventional farms, organic farms had lower milk production, lower replacement rate, higher somatic cell count, and a much higher rate of crossbreeding. Actual culling rate was 21%, and the main causes were fertility, mastitis, feet and legs, production, and old age. The major areas of concern expressed by organic dairy farmers were related to grazing traits, fertility, health, and longevity. An organic total merit index was developed based on the subjective scores for traits with a genetic evaluation in Canada. The relative weights of production to fitness traits (28:72) were substantially different from those in the Canadian Lifetime Profit Index (54:46), but similar to those used in conventional indices in Sweden and Denmark and in the Swiss organic index. The overall weight on health traits was 2.5 times higher in the organic index and, among fitness traits, the emphasis was substantially higher for lactation persistency, somatic cell score, and body capacity. Correlations between the organic index and Lifetime Profit Index were 0.88 for all bulls proven in Canada, 0.70 for the top 1,000, and 0.65 for the top 100, indicating that a different group of bulls would rank at the top of these 2 indices. When the top 100 bulls for either index were compared, those selected for the organic index were about 0.5 standard deviations lower for all yield traits, but were much better for body capacity and somatic cell score, and 0.25 standard deviations higher for herd life, feet and legs, udder conformation, and lactation persistency. Given the small population size, a separate breeding program for an organic management system is not viable in the foreseeable future. However, the organic index would allow producers to rank proven bulls in accordance with their perceived needs.

Review: Towards the agroecological management of ruminants, pigs and poultry through the development of sustainable breeding programmes. II. Breeding strategies

“…In some countries, specific selection indices for organic dairy cattle have been developed, based on subjective scores determined by organic farmers for traits with a genetic evaluation; for example, the ecological breeding index in Switzerland in 2000 (Haas and Bapst, 2004) and the organic total merit selection index in Ontario in 2006 (Rozzi et al, 2007). Initially, the relative balance between production and functional traits differed substantially from that of the corresponding national total merit indices (Rozzi et al, 2007;Fric and Spengler Neff, 2014).…”

“…Initially, the relative balance between production and functional traits differed substantially from that of the corresponding national total merit indices (Rozzi et al, 2007;Fric and Spengler Neff, 2014). However, in 2014, because of the greater weighting given to functional traits in the national selection index, the ecological selection index was abandoned for Swiss dairy cattle (Fric and Spengler Neff, 2014).…”

Evaluating mountain goat dairy systems for conversion to the organic model, using a multicriteria method

“…Weights of indicators for calculating the OLPI were based on the importance conferred to them by the experts and were transformed to a percentage scale, as in Rozzi et al (2007) to build the organic total merit index for organic dairy farmers. If the method is used to compare farms of different regions, OLPI should not be considered, as the weighting coefficients must be adjusted in accordance with specific local criteria (Gallopín, 1997).…”

“…Previous studies report those indicators that have been used to analyse farm sustainability (Coffey et al, 2004;Nahed et al, 2006;Galá n et al 2007;Peacock and Sherman, 2010); animal welfare (Napolitano et al, 2009;Phythian et al, 2011), environmental effects, animal welfare and milk quality of organic farms (Mü ller-Lindenlauf et al, 2010), and differences, in general, between organic and conventional farms (Nauta et al, 2006;Rozzi et al, 2007). Other studies evaluate the technical and economic performance of organic farming ).…”

Nutrient budgets of Ontario organic dairy farms

“…But densities on organic dairy farms are still typically lower than those on conventional farms (Nicholas et al 2004 (1 yr (1 ). This is partially attributable to a shift in herd genetic composition, emphasizing fitness rather than production traits, on these farms (Rozzi et al 2007). Milk production per hectare was 43% lower (2767 vs. 4822 kg ha -1 yr -1 ) on organic farms (ODFAP, Annual).…”