Effect of decreasing ideal protein levels on performance results and nitrogen efficiency of growing-finishing gilts.

This study examined the effect of decreasing ideal protein concentrations on performance and nutrient efficiency. The experimental diets contained 100%, 90%, 80% or 70% of the ideal dietary protein level (Diet 100%, 90%, 80% and 70%, respectively) estimated in previous experiments with pigs of the same genetic background. The four different treatments were divided among 16 pens of six pigs each. The average initial and final body weight were 20.8 +/- 1.1 and 107 +/- 3 kg, respectively. Three-phase feeding was applied (BW 20-40 kg, 40-70 kg and 70-110 kg). The dietary ileal digestible (ID) methionine + cystine, threonine, tryptophan, isoleucine, valine, and leucine contents expressed as percent of ID lysine were 63, 72, 22, 60, 68, and > 100%, respectively. The lysine to protein ratio was kept constant at 6.8%. Between 21 and 106 kg BW the best performance was achieved on Diet 90%. Diet 70% led to significantly worse results. Although lean meat percentage did not differ, protein content of the carcass was lower on Diet 70% than on Diets 90% and 100%. Decreased protein concentrations increased crude protein efficiency and consequently decreased nitrogen excretion most at the 80% level. If protein varies together with digestible amino acid content, it can be concluded that Diet 80% may be the best choice for the environment and for profitability. If protein content stays at a fixed level, Diet 90% may be the safest choice.

Response of 40-70 kg barrows and gilts to increasing ideal protein concentrations in the diet.

In Belgium, crossing a hybrid dam with a Piétrain sire leads to a rather lean and meaty fattening pig type. A digestibility trial and a performance trial were carried out to determine protein needs of this pig type. Six experimental diets with increasing protein content were formulated with 0.65-1.25% apparent ileal digestible lysine. The feeds were formulated to the ideal protein composition, with lysine as the reference amino acid. Standardised and apparent digestible amino acid values of the extreme diets were measured in a digestibility trial with four gilts cannulated at the end of the ileum, with an average initial and final BW of 39.1 kg and 55.3 kg, respectively, using a protein-free feed to estimate the basal endogenous N-losses. A performance trial at 13-18 weeks of age (40-70 kg BW) was performed with barrows and gilts separately at six protein levels, balanced in lysine, threonine, methionine and tryptophan. The experiment consisted of 11 pens (of 5 animals) per treatment and per sex. Average daily gain (ADG) and feed conversion ratio (FCR) reached maximal performance within the experimental lysine range for both sexes. Based on the ADG-data for barrows and on the ADG- and FCR-data for gilts, a protein level for optimal performance corresponded with a standardised ileal digestible lysine concentration of 0.89% for barrows and of 1.07-1.09% for gilts.

Effect of seven hours intermittent suckling and flavour recognition on piglet performance.

A low feed intake during the first days after weaning is predisposing for weaning diarrhoea and weight loss. In this experiment we tried to increase the feed intake of the piglets after weaning by stimulating the solid feed intake during the last two weeks before weaning by separating them from the sows for 7 h/d. In addition, the effect of flavour recognition and the interaction of flavour recognition with intermittent suckling were tested. In two consecutive weaning rounds, sows were divided over two compartments with 7 to 10 sows each. They were assigned to one of four treatments in a two factorial design: control housing/control feed (n = 7); control housing/ flavoured feed (n = 8); intermittent suckling/control feed (n = 7); intermittent suckling/ flavoured feed (n = 9). After weaning, for each round 3 pens of 6 pigs were selected per treatment group. All these piglets received the same feed with the same flavour at the same concentration. Contrary to the expectations, intermittent suckling decreased the solid feed intake during the last two weeks before weaning. Flavour addition to the creep feed did not increase feed intake or other performance parameters before and after weaning, nor did it interact with intermittent suckling. Although after intermittent suckling pigs ate less creep feed before weaning, they did not perform worse after weaning. However, to increase feed intake after weaning, longer periods of separation might be necessary.

Role of intrinsic search cues in the formation of consumer preferences and choice for pork chops.

This study investigates the role of drip, colour, marbling and fat cover as intrinsic search cues in the formation of pork chop preferences and individual determinants. Data are collected from a sample of 443 pork consumers in Belgium through using repeated selection of chops from randomised photobooks and questionnaires including socio-demographic, attitudinal and behavioural variables. Data analysis includes mixture regression analysis, bivariate descriptive statistics and the estimation of multivariate probit models. Consumers sampled in this study prefer pork chops without fat cover. Preference for fat cover is stronger among male, 35+ aged consumers with lower levels of awareness of the relation between food and health and who like pork for other reasons than taste and nutritional value (all p<0.05). Preference for colour is equally consistent within an individual, though fifty-fifty light-dark, with dark chops being more preferred by 35+ aged consumers (p<0.05). Preferences for marbling and drip are not consistent and not determined by joint socio-demographic, attitudinal and behavioural factors. Preferences for cue levels are not correlated, except a weak relation between preference for dark chops without drip (r=0.116). Preferences are apparently formed by deductions with the use of single cues as key information, mainly based on fat cover or colour, and random choice on marbling and drip.