•We observed no significant effect of dietary salt level on piglet performance•Increasing dietary salt levels led to worse fecal consistency scores•Effects were independent of dietary crude protein ...content and energy concentration
Recent research has shown that salt levels of minimal 3.5 g/kg diet result in best performance in piglets between 7 and 11 kg. In the US, pig diets tend to have higher salt levels and higher crude protein (CP) levels than in Europe. Higher CP levels may lead to higher protein breakdown, while higher salt levels may lead to increased water consumption, which might facilitate nitrogen clearance through the kidneys. Therefore, we hypothesized that high salt levels are more important when the pigs receive a high CP diet. For this experiment, 96 pens of 5 piglets were divided over 8 treatments in a 2 × 4 factorial design with 2 protein levels (189 vs 223 g/kg) and 4 salt levels (1.9, 2.5, 3.1, and 3.8 g/kg in the low protein diet and 1.9, 2.6, 3.2, and 3.9 g/kg in the high protein diet). Different salt levels were obtained by exchanging SiO2 for NaCl. The low protein diet was formulated to contain 11.8 g SID lysine and 9.85 MJ net energy/kg diet, while the high protein diet had 12.5 g SID lysine and 10.40 MJ net energy/kg diet. Salt level did not affect performance nor did it interact with crude protein level. Fecal consistency worsened as salt levels increased during the first week after weaning. The latter might be a result of either increased water consumption or increased osmotic pressure in combination with the piglets’ limited absorption capacity shortly after weaning, especially when receiving diets without zinc oxide or antibiotics. The higher nutrient density in the high protein diet resulted in lower feed intake with similar growth, leading to improved feed efficiency per kg diet, but not per MJ of net energy consumed. Based on the present experiment, we could not confirm our hypothesis that increased protein levels lead to higher sodium requirements in weaned piglets.
A continuation method is used to study Rayleigh–Bénard convection in a non-Newtonian fluid inside a parallelepiped cavity. The cavity has its length equal to twice the side of the square ...cross-section. Shear-thinning and shear-thickening Carreau fluids are considered. The focus is put on the two stable branches which exist in the Newtonian case, a stable primary branch of transverse rolls $B_1$ and a primary branch of longitudinal roll $B_2$, stabilized beyond a secondary bifurcation point $S_2$. Although the primary bifurcation points are unchanged, the non-Newtonian properties strongly modify the bifurcation diagram. Indeed, for a shear-thinning fluid, the stable solutions can exist at much smaller Rayleigh numbers ${Ra}$, on subcritical branches beyond saddle-node points $SN_1$ and $SN_2$, and small perturbations can be sufficient to reach them. In agreement with Bouteraa et al. (J. Fluid Mech., vol. 767, 2015, pp. 696–734), the change of the primary bifurcations from supercritical to subcritical occurs at given values of what they define as the degree of shear-thinning parameter $\alpha$. Moreover, the value of the Rayleigh number at the saddle-node points can be approximated by a simple expression, as proposed by Jenny et al. (J. Non-Newtonian Fluid Mech., vol. 219, 2015, pp. 19–34). In the case of a shear-thickening fluid, the branches remain supercritical, but the secondary point $S_2$ is strongly moved towards larger ${Ra}$, making it more difficult to reach the longitudinal roll solution. Energy analyses at the bifurcations $SN_1$, $SN_2$ and $S_2$ show that the changes of the corresponding critical thresholds ${Ra}_c$ are connected with the changes of the viscous properties, but also with changes of the buoyancy effect.
We study experimentally the primary instability of a visco-plastic film flow down an inclined plane. The experimental set-up is a channel with a varying slope angle, in which a permanent flow of a ...Herschel–Bulkley fluid (carbopol or kaolin) is established. Controlled perturbations are imposed at the entrance of the channel to generate surface waves, and their downstream evolution is observed with a laser sensor system measuring the local fluid thickness. Growth rates and cutoff frequencies are obtained after processing the thickness signal, and experimental critical Reynolds and Bingham numbers are deduced. We find that the experimental stability map obtained is well described by the pseudo-plug model of Balmforth & Liu (J. Fluid Mech., vol, 519, 2004, pp. 33–54), a model obtained after neglecting the film thickness compared with its length. This is not the case for dispersion effects (growth rates, cutoff frequencies, phase speeds), for which a more accurate model is needed.
•Pork production significantly contributes to the emission of greenhouse gases.•We evaluated the carbon footprint of pig feed intake.•A strong impact of both slaughter weight, sex and feed ...composition was observed.•Higher slaughter weights and fattening barrows implied a lower sustainability.•A soy-free finisher feed allowed a constant footprint with increasing bodyweight.
The impact of pork production on global livestock’s greenhouse gas emissions is substantial. Understanding the factors influencing these emissions is crucial in achieving a more sustainable pig husbandry. In two independent experiments, the impact of slaughter weight on the carbon footprint (CFP) of pig feed intake (CFPFI) was evaluated for growing-finishing pigs of different sexes (entire males (EM), barrows (BA), immunocastrates (IC) and gilts (GI)). In experiment 1 118 animals were raised individually in experimental conditions. In experiment 2 384 animals were housed in group (four pigs per pen), in controlled commercial farm circumstances. All animals were fed ad libitum in a three-phase feeding regime and slaughtered at different BW, ranging from 110 to 148 kg (experiment 1) and from 99 to 138 kg (experiment 2). When only the fattening period was considered, the CFPFI was expressed per kg carcass growth. When the production of piglets was also taken into account, the CFPFI was calculated per kg carcass weight. For all sexes, the heavier the pig, the higher the CFPFI per kg carcass growth (P < 0.05, experiment 1; P < 0.001, experiment 2) and per kg carcass weight (P < 0.05, experiment 1; P < 0.01, experiment 2). In addition, BA had a significantly higher CFPFI per kg carcass growth and per kg carcass weight compared to EM and IC and to EM, IC and GI in respectively experiments 1 and 2 (P < 0.001). When performing a desk study with a soy-free (i.e. reduced CFP) feed in the third phase of experiment 2, slaughter weight no longer affected the CFPFI per kg carcass growth (P = 0.133) and per kg carcass weight (P = 0.856). A higher slaughter weight thus implies a lower sustainability, unless a sufficiently low-CFP feed is provided in the finisher phase.
•Do different types of boars cope differently with alternative ingredients?•No significant interaction between the type of boar and diet.•Type of boar did affect performance, carcass quality and ...intramuscular fat content.•Type of diet did affect performance, carcass quality and digestibility.•Feeding sustainable diets does not appear to require any change in breeding goals.
For many years, pig production has focused on maximizing performance by selecting for maximal muscle growth and feeding diets that allow the animals to express their genetic potential. However, it is unclear whether this selection for muscle deposition has affected the capacity of pigs to cope with by-product-based diets, which rely on fat as the primary energy source instead of starches and sugars. Therefore, an experiment was set up to investigate if different types of boars affect how their progeny cope with alternative ingredients in the diet, with a possible need for adapted breeding schemes. Two types of boars within the Piétrain sire line were used based on either a high or low estimated breeding value for daily feed intake (HFI: high feed intake, low feed intake). When their progeny reached 14 weeks of age, two dietary strategies were compared: a control (CON) vs a by-product-based diet high in fat and fiber (HFF). The CON diet was mainly based on cereals (corn, wheat, barley) and soybean meal. The HFF diet was formulated to contain the same net energy, CP and digestible amino acid levels without any cereals or soybean meal. In total 192 animals were included in the experiment (48 animals/type of boar/diet) and performance, digestibility, carcass and meat quality were compared. None of the parameters showed a significant interaction (P < 0.05) between the type of boar and diet, suggesting that shifting to diets that are less prone to feed-food competition is equally feasible in different types of pigs. Type of boar did affect performance, carcass quality and intramuscular fat content. HFI pigs showed higher daily feed intake (DFI) and daily gain (P < 0.001), with no significant difference in feed conversion ratio (P = 0.205), lower carcass quality (P < 0.001) and higher intramuscular fat content (P = 0.030). For both boar types, pigs fed the CON diet performed better, with a higher daily gain (P = 0.028), DFI (P = 0.011) and dressing yield (P = 0.009) and better digestibility (P < 0.001), but without differences in feed conversion ratio or meat quality. In conclusion, there was no indication that pigs differing in feed intake capacity cope differently with a high-fat, high-fiber diet based on by-products. Different types of pigs may cope well with diets that are less prone to feed-food competition.
Changes in the drinking behaviour of pigs may indicate health, welfare or productivity problems. Automated monitoring and analysis of drinking behaviour could allow problems to be detected, thus ...improving farm productivity. A high frequency radio frequency identification (HF RFID) system was designed to register the drinking behaviour of individual pigs. HF RFID antennas were placed around four nipple drinkers and connected to a reader via a multiplexer. A total of 55 growing-finishing pigs were fitted with radio frequency identification (RFID) ear tags, one in each ear. RFID-based drinking visits were created from the RFID registrations using a bout criterion and a minimum and maximum duration criterion. The HF RFID system was successfully validated by comparing RFID-based visits with visual observations and flow meter measurements based on visit overlap. Sensitivity was at least 92%, specificity 93%, precision 90% and accuracy 93%. RFID-based drinking duration had a high correlation with observed drinking duration (R 2=0.88) and water usage (R 2=0.71). The number of registrations after applying the visit criteria had an even higher correlation with the same two variables (R 2=0.90 and 0.75, respectively). There was also a correlation between number of RFID visits and number of observed visits (R 2=0.84). The system provides good quality information about the drinking behaviour of individual pigs. As health or other problems affect the pigs' drinking behaviour, analysis of the RFID data could allow problems to be detected and signalled to the farmer. This information can help to improve the productivity and economics of the farm as well as the health and welfare of the pigs.
•This paper explores if lowering the energy level of finishing diets has advantages.•A high-energy diet results in a better feed conversion and growth of immunocastrates.•A high-energy diet is ...economic profitable and has almost no effect on meat quality.•A high-energy diet has generally positive ecological benefits.•No reason to change standard energy concentration of diets of immunocastrates.
Immunocastration, a technique consisting of two vaccinations against gonadotropin-releasing hormone (GnRH), can be used as alternative to surgical castration of piglets. It reduces boar taint and allows higher economic and ecological efficiency compared to barrows. The feeding strategy of immunocastrates, however, can still be improved. After second vaccination, when immunisation becomes fully effective, feed intake of immunocastrates increases sharply. This study aimed to investigate whether energy intake of immunocastrates after second vaccination could be reduced by lowering the dietary energy level of the finishing phase, without negatively affecting animal performance and quality of pork production. We hypothesised that immunocastrates already reach their limits in voluntary feed intake after second vaccination, and therefore would not be able to compensate the lower dietary energy level, in contrast to barrows. Therefore, this study aimed to assess the effect of high-energy diet (HE, net energy (NE) = 10.2 MJ/kg) compared to low-energy diet (LE, NE = 8.8 MJ/kg) in barrows and immunocastrates and as a reference, gilts and entire male pigs on a standard high-energy diet were included. CP and standardised ileal digestible amino acid levels were similar in both diets. For each treatment, eight pen replicates of six pigs per pen were evaluated on performance, carcass quality, meat and fat quality, digestibility, economic and ecological sustainability, behaviour and effectiveness of immune response. No difference in feed intake of immunocastrates between LE and HE could be demonstrated. As a result, daily energy intake of immunocastrates was higher on HE compared to LE, which resulted in a higher daily gain on HE. Feed conversion ratio (FCR) of immunocastrates on HE did not differ significantly with FCR of entire males. Barrows did not show higher average daily gain on HE compared to LE. Nitrogen efficiency was better in HE compared to LE, without negative effects on digestibility, carcass quality, economic parameters, behaviour or immune response. Small positive effects on the palatability of the meat of immunocastrates on HE were observed, although consumers did not prefer one of both feeds. Immunocastration was successful in reducing sexual and aggressive behaviour as well as in lowering the prevalence of boar taint from 15% in EM to 0% in immunocastrates. However, in two out of 96 immunocastrates (one on HE and one on LE), the immunocastration was not fully effective. In conclusion, this study did not show advantages of feeding immunocastrates or barrows a low-energy diet.
•We studied the effect of sex category on environmental sustainability.•Castrating impairs environmental sustainability in all trials.•Differences between trials are larger than differences between ...sex categories.•Improving feed efficiency and tailoring diets to animal’s needs is crucial.•Ending physical castration supports the reduction in nutrient excretion.
The environmental impact of livestock production is under scrutiny nowadays and is being situated both on a global level and local level. On a global level, the global warming potential (GWP) of meat production is criticised. On a local level, the excretion of nitrogen (N) and phosphorus (P) is of concern as excess nutrients may lead to water eutrophication and soil acidification. The ERA-NET project SuSI evaluated if immunocastration may act as an ecologically, socially and economic more sustainable alternative compared to pork production with surgical castrates (SCs) and boars (BOs). Here, we report the environmental impact of immunocastrates (ICs) vs SC and BO, based on four trials carried out by European SuSi partners. More specifically, we aimed to compare IC with SC and BO in terms of GWP, N and P excretion per kg of pork production and test if this differed between experiments. There was an interaction between trial and sex category (PTrial × Sex category < 0.005) for all environmental sustainability parameters. Surgical castrates performed worse (higher carbon footprint of the feed intake, N and P excretion, lower N and P efficiency) compared to IC and BO, but the size of the effect was trial dependent. Immunocastrates scored intermediate, with mostly no significant differences from BO in most trials, but with significantly better values compared to SC. Over trials, the carbon footprint of the feed intake (land use change inclusive) per kg lean meat gain in the growing-finishing phase was 9–16% lower for IC vs SC and 9–22% lower for BO vs SC. Nitrogen efficiency of IC and BO was 7–10% and 9–14%, respectively, higher compared to SC. Phosphorus efficiency of IC and BO was higher than that of SC by 6–14% and 9–17%, respectively. Per kg of lean meat gain in the growing-finishing phase, IC excreted between 14 and 19% less N and between 14 and 24% less P than SC. For BO, it was between 14 and 27% less N and between 14 and 31% less P than SC. Differences between trials were larger than differences between castration strategies and trial design may have amplified the observed effects. Improving feed efficiency, adapting the feed to the needs of the animal (avoiding excess nutrients) and choosing low-impact ingredients are key for improving the environmental sustainability of pig production. Ending physical castration is another step to attain this goal.
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