Daily gain, food intake and food efficiency in pigs during the growing period

Abstract

The non-linear model y = ae {~hw~Llw ) was fitted to weekly calculated daily gain (DG), daily food intake (FI) and food efficiency (FE) of 653 barrows and gilts fed ad libitum or restrictedly during a growing period from 27 to 108 kg live weight. Where y was DG, FI or FE, W was live weight and a, b and c were parameters. The model fitted well to the expected course of the traits, with an accuracy similar to that of quadratic polynomials. Parameters for one trait could simply be derived from the parameters for the other two traits. For each trait, four basic patterns were distinguished, depending on the signs of b and c. Curves with a maximum (b > 0 and c > 0) occurred most frequently. In cases of curves with a maximum, the model could be reparameterized to a model with parameters having a simple biological meaning.Coefficients of determination in barrows averaged 0-29 for DG, 0-88 for FI and 0-45 for FE, whereas these values were somewhat lower in gilts. With ad libitum feeding, a DG curve with a maximum was fitted in proportionately 0-83 of the barrows and 0-61 of the gilts. The maximum DG was on average at live weights of 64 kg for barrows and 77 kg for gilts. A maximum in the FI curve was predicted in proportionately 0-60 of the barrows and 0-39 of the gilts. Curves for DG and FI in gilts were less curvilinear than in barrows. FE curves, with ad libitum feeding, had a maximum in proportionately 0-59 of the barrows and 0-52 of the gilts. This predicted maximum FE was, on average, before the start of the growing period. Gilts had a higher FE than barrows from 35 kg body weight onwards, and the difference increased with increasing live weight. Differences in FE between ad libitum and restricted feeding were small, with a tendency for animals fed at a restricted feeding level to be more efficient at the end of the growing period.Average FE curves and individual FI or DG curves were used for indirect prediction of individual DG or FI curves, respectively. The correlation between directly and indirectly predicted values of DG and FI at live weights of 30, 65 or 100 kg was about 0-7 in ad libitum fed barrows and gilts, and greater than 0-8 in pigs fed at a restricted level. This indicates that the model is suitable to predict and control the course of individual daily gain by influencing the course of food intake.

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“…We used the nonlinear model: (Kanis & Koops, 1990) to present the course of daily weight gain, daily feed intake and feed efficiency. In this model y is the dependent variable (DWG, DLG, FI, FE, FI%), x is the independent variable (total body length or total body weight) and a,b,c are parameters.…”

“…Feed efficiency, feed intake and daily gain are strongly related to each other (Kanis & Koops, 1990). Therefore, it is possible to shift the growth curve to a more economic one by manipulation feed intake (Parks, 1982;Krieter & Kalm, 1988;Kanis & Koops, 1990). Thus, precise knowledge of the course of these traits can be used in selection and breeding purposes (Krieter & Kalm, 1988;Kanis & Koops, 1990).…”

“…Therefore, it is possible to shift the growth curve to a more economic one by manipulation feed intake (Parks, 1982;Krieter & Kalm, 1988;Kanis & Koops, 1990). Thus, precise knowledge of the course of these traits can be used in selection and breeding purposes (Krieter & Kalm, 1988;Kanis & Koops, 1990). To do so, the limits and mathematical relations of these traits must be known, in order to manipulate the feed intake, either by feeding management or selective breeding (Kanis & Koops, 1990).…”

The effect of a high monounsaturated fat diet on body weight, backfat and loin muscle growth in high and medium-lean pig genotypes

“…Our results are in line with Hamilton et al (2003) who indicated that genotypes with leaner carcasses, such as Pietrain crosses, present slower growth rates and a lower food intake than medium-lean genotypes. Kanis & Koops (1990) evaluated growth differences between high lean and medium lean genotypes and reported a higher daily gain in fatter genotypes.…”

A new mathematical model for combining growth and energy intake in animals: The case of the growing pig

“…sigmoid shapes and diminishing return behaviours. Analysis of intake and growth data is usual done separately by fitting nonlinear functions of time (Kanis and Koop, 1990;Lopez et al, 2000). Another approach for modelling growth and intake curves in animals is to describe the body weight (BW) as function of the cumulated intake (Andersen and Pedersen, 1996).…”