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A significant relationship between the ESR gene and litter size has been reported for a range of Meishan synthetic and Large White lines (Rothschild et al., 1995). The effect of one copy of the positive (B) allele in a European 50% Chinese Meishan synthetic (L93) was estimated as +0.79 pigs born alive per litter in the first parity (Southwood et al, 1995). It is therefore of interest to incorporate the positive allele into a comercial parent gilt, the growing performance and soundness of these animals also being of importance. The objective of this trial was to evaluate the effect of the ESR gene on growth and performance traits in a commercial type background.
The choice feeding of pigs has been shown in many experiments to allow the individual pig to express its own needs and thereby grow more efficiently and show its full potential.
The objective of this experiment was to test whether pigs representing 7 distinct genotypes, including Large White, Landrace, Pietrain, Duroc and Meishan, were able to select their dietary crude protein (CP) in relation to energy requirements under a choice feeding regime, and whether these differences were related to growth and performance.
The strawflow® system is designed to provide pigs with free access to straw without the operational and agricultural constraints of a deep bedded system and could provide an alternative type of weaning accommodation. A trial was conducted to evaluate the potential of three different strawflow® systems. These differed only in means of heating and ventilation.
Two trials were conducted consisting of twenty four and twelve weekly groups of pigs. Eighty pigs were split sex weaned into four strawflow® pens in the same room, on a weekly basis, and remained in the system for forty days. All other pigs to be weaned that week were weaned into the flatdecks. (8827 pigs total)
An average weaning weight was recorded for each batch of piglets moved into the strawflow® and flatdecks and each pig was individually weighed on leaving a system. Feeding regime was the same in each system with a creep feed for approximately one week post weaning before moving onto a grower ration for the remainder of the trial. All food given to a flatdeck room and one side of a room in the strawflow® building was recorded.
Available technology allows pig breeding companies to automate feed intake recording during performance test. This provides data on ‘average daily feed intake’ as recorded with more traditional manual systems. It also results in feed intake curves, i.e. the relationship between ‘days on test’ and ‘daily feed intake’. This information can be used in different ways. The feed intake curve may be described using sophisticated linear or non-linear models; these may describe the feed intake curve accurately, but model parameters cannot be used easily in genetic/economic evaluation in the context of a breeding programme. A simple method to describe feed intake curves is used in this paper, allowing for easy interpretation of the results. The objective is to study the impact of existing selection procedures on the feed intake curve and the utilisation of variation in its shape in pig breeding.
Performance test data of 1331 boars of a Large White based line, collected from November 1990 to March 1993 were analysed. Boars are tested over a 12 week period, starting at approximately 30 kg. Feed intake data are recorded with the Hunday FIRE system.
Genetic improvement of pigs relies heavily on improving feed conversion and controlling feed intake capacity. For this purpose it is vital to measure feed intake of individual pigs. Traditionally this has been achieved by keeping pigs singly or in sib-pairs in small pens. Such facilities are expensive to build and are difficult to design to cater adequately for pigs over a wide range of weights and at low stocking density. Keeping animals in small pens is less than satisfactory from a welfare aspect.
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