Predicting milk supply

Being able to predict future milk production is an important tool for dairy producers and processors to avoid a shortfall or an overproduction. The question posed by the Quebec dairy industry was to see whether there is a suitably accurate means of predicting production in the short to medium term; that is to say for up to about 300 days ahead, i.e. 9-10 months. Presently prediction about future production are made considering total provincial shipments from one month to the next and comparing these with previous years with the objective of estimating whether there will likely be an increase or a decrease. Rather than simply looking at the total shipments registered with the Federation des Producteurs de Lait du Quebec (FPLQ) the question is whether we can look at the data from the production of each cow in each herd on the milk recording at le Programme d'Analyse des Troupeaux Laitiers du Quebec (PATLQ) to better predict future production.[...

Impact of Descriptive Linear Type traits on Functional Herd Life of Quebec Holsteins assessed by Survival Analysis

Longevity is one of the most important components of dairy cow profitability. The economic advantage of longevity lies primarily in retaining productive, healthy and trouble-free cows as long as possible. Functional herd life is defined as the ability of a cow to remain sound and healthy in a herd, independently of her level of production.[...

Correlations between Herd Life and Type Traits in Quebec Holsteins

Long productive life is a primary breeding objective of dairy farmers. Herd life and lifetime profitability are two of the most important factors influencing a cow’s profitability. Various tools have been introduced to aid farmers in obtaining efficient, high producing, sustainable cows, of which type traits, which evaluate an animal’s physical characteristics, are the most popular. Dairy producers have bred for high producing and healthy cows, and many of their decisions are based on a cow’s conformation traits. The objective of this study was to estimate the relationship between various lengths of productive life and type traits for Quebec Holstein cows.[...

Genetic Analysis of Herd Life in Quebec Holsteins Using Weibull Models

A genetic study was conducted to analyze herd life in Quebec Holstein herds utilizing Weibull regression models. It has been shown that this class of models are more appropriate to analyze herd life data in dairy cattle than the usual linear models (Ducrocq, 1987). They belong to the general class of survival models known as “proportional hazards models”, which assume that the hazard functions for different individuals are proportional over time. The possibility to include timedependent covariates and to define different strata add flexibility to these models in situations where the assumption of proportionality does not hold. A Bayesian approach for the estimation of breeding values for herd life traits using Weibull models has been recently described by Ducrocq and Casella (1996) and France and Austria have already adopted these methodologies to estimate official sire proofs for herd life. Canada publishes sire genetic evaluations for herd life based on an index that includes an indirect herd life estimate (based on type) and a direct herd life estimate which is obtained by linear models. The research reported here is the first attempt to utilize survival models for sire evaluation using Canadian data, and may be used to infer whether the methodology to produce official proofs for herd life should be revised.[...

Phenotypic Impact of Conformation Traits on Herd Life Assessed by Survival Analysis

Many farmers believe that selection of dairy cows based on conformation traits will increase herd life indirectly. Although only few type traits have been reported to have significant genetic correlations with herd life traits, conformation still influences the culling decision making process in dairy herds. It is reasonable to assume, for example, that those herds which have their cows classified for type would put some emphasis on conformation when selecting their cows. The Canadian type classification program uses a linear scores system, in which physical characteristics of the cows are actually “measured”. The type scores are posteriorly combined into composite traits (score-card traits), which describe more general aspects of the cow conformation. These composite traits tend to receive more attention than individual scores, because they are easier to interpret, and they probably would be the traits considered by dairymen when making culling decisions.[...