Lifetime productivity of conventionally and precision-fed broiler breeders

Abstract

A precision feeding (PF) system was developed to increase broiler breeder lifetime reproductive performance through improved flock uniformity. The current study consisted of 2 rearing and 3 laying treatments. From 0 to 22 wk of age, 480 Cobb male grandparent line pullets and 80 Cobb MX males were fed once daily as a group (CON), or individually with a PF system. Pullets were housed in 6 replicate pens of 40 birds, and cockerels in one pen per treatment. During lay, CON and PF treatments continued, and a third treatment was added, where PF-reared birds were transitioned to conventional feeding (PFCON; n = 3 pens). At photostimulation (22 wk of age), all pens had 24 hens and 2 roosters. Birds were allowed to mate naturally to 52 wk. Analysis of variance was conducted, and Tukey-adjusted means were reported as different where P ≤ 0.05. Mean BW was near the target BW in all treatments. At photostimulation, PF pullet BW CV was 2% vs 14% in CON pullets. Cumulative feed conversion ratio during rearing was lower in PF treatment pullets, which ate 3% less than CON pullets. Pullets in the PF treatment received 10 meals spread throughout each day, compared with one meal per day in the CON treatment. Increased feeding frequency would reduce diurnal fluctuations in nutrient supply, which may explain why PF pullets had 1.2 times the breast muscle weight of CON pullets at 22 wk. There was no treatment difference in abdominal fatpad weight at 22 wk. The PF treatment had 3.8% higher fertility and 1.3% lower egg weight CV compared with the CON treatment. Egg production in PF and PFCON treatments was 0.73 and 0.89 times that of the CON treatment, respectively. It is hypothesized that metabolic changes in PF pullets provided an insufficient metabolic trigger for sexual maturation. It follows that relaxing feed restriction may increase fat deposition and egg production in PF broiler breeders.

Modeling life-time energy partitioning in broiler breeders with differing body weight and rearing photoperiods

“…Meal:visit ratio was much lower (around 20% for all treatments) in the rearing phase compared with the laying phase (around 80%) for those treatments that commenced egg production earlier (8L:16D and high BW treatment; Figure 8 ). The meal:visit ratio was in line with results from Zuidhof (2018) who looked at Cobb grandparent pullets and found an average meal:visit ratio of 17% between week 2 and 22. However, the meal:visit ratio of the 12L:12D standard BW treatment stayed around 30% in the laying phase, indicating these birds were hungrier compared with those treatments that had commenced egg production.…”

Intermittent fasting in chickens : Physiological mechanisms and welfare implications for broiler breeders

“…We argued that growth heterogeneity is maintained by feed restriction rather than caused by it. While the recent studies employing precision feeding systems have achieved extremely uniform flocks, they also highlight an enormous variation in attempts to access feed in these experiments which points towards large individual differences in feeding motivation (Zuidhof, 2018).…”

“…The exact eating pattern allowed by the precision feeding system is a combination of competition for entry into the cubicle and limitations imposed on eating time by the experimenters. Because early trials allowing for longer eating times (up to 10 min) showed that feed intake rates decrease logarithmically over time, subsequent experiments have used a maximal meal time of 1 min (Girard et al, 2017a;Zuidhof et al, 2017;Zuidhof, 2018). With this setup, precision-fed birds eat approximately 8-10 meals per day with an average meal size of around 8-10 g, although the total number of visits to the feeder was much higher and averaged 51 visits (full range: 28-138 visits) per day and bird (Girard et al, 2017a;Zuidhof et al, 2017;Zuidhof, 2018).…”

“…While precision feeding has proven extremely good at producing homogeneous flocks, with reported coefficients of variance (CVs) in the single digits and frequently below 2% as compared with CVs in the 11-14% range in conventionally fed control groups (Zuidhof, 2018;Zuidhof et al, 2017), improvements in other parameters of welfare and productivity have been miniscule at best. The frequent feedings in this system appear to reduce FCRs somewhat (from 4.89 g feed/g bird to 4.06 g feed/g bird during the 10-23-week period; Hadinia et al, 2018), but total egg production was higher in conventionally fed controls (Zuidhof, 2018).…”

Large-Scale Phenotyping of Livestock Welfare in Commercial Production Systems: A New Frontier in Animal Breeding

“…In the case of poultry, precision feeding stations in broiler breeders can provide individual information about their performance in terms of growth rate and feed intake during rearing and lay (Hadinia et al, 2019). This information allows individual and automatic management of the feed restriction level and improve body weight uniformity in the flock (Zuidhof, 2018). For breeding selection purposes, individual performance records with precision feeding enable selection for feed efficiency.…”