American Association of Family and Consumer Sciences

Abstract The symbiotic relationship between humans and animals is so intwined that it can be considered a primary factor in the shaping of modern-day societies, including our current livestock production systems. This relationship is complex and involves the use of animals for food, labor, materials as well as companionship, entertainment and even religious practices. There is no question that significant changes in the care, understanding and acknowledgement of animals as sentient beings have evolved over the past 100 yr. Early misunderstandings of the differences between those advocating for animal rights (any use of animals is unacceptable) versus those advocating for animal welfare (humane use of animals is acceptable) resulted in push back and mistrust by industry stakeholders. Initially, animal welfare advocates promoted basic aspects of animal care such as being treated humanely and ensuring that animals were not subjected to unnecessary suffering. However, current ideology includes the ability of an animal to lead a natural life, taking their feelings and needs into consideration. Advances in veterinary and animal welfare science have been key factors in improving our understanding of optimal animal welfare and its close association with animal health. Examples from Canadian beef cattle production will be used to show how cattle health and welfare have evolved in the past century and will cover painful management procedures, transport, handling, as well as the management of vulnerable and ill cattle. Livestock health and welfare in Canada will continue to evolve and will be shaped by factors including societal views, food safety, production costs, environmental impacts, new technologies and continued research.

Abstract Immune system activation redirects dietary nutrients to defense mechanisms, thereby impairing growth performance of pigs. Supplementing pigs with functional amino acids (AA) such as Met, Thr and Trp was shown to support the immune system and reduce the negative effects on growth. However, pigs respond differently to immune stressors which increase herd variability. In this context, individual precision feeding (IPF) might be an alternative approach to reduce herd variability and increase nutrient efficiency in immune challenged pigs. This study aimed to evaluate growth performance, body composition, nitrogen (N) efficiency and haptoglobin and triglycerides serum concentration in growing pigs raised in poor sanitary conditions (PoorSC). The PoorSC was characterized by oral inoculation with 2 × 109 cfu of Salmonella typhimurium and manure spreading on the pen floor. Sixty gilts (23 ± 2.8 kg BW) were distributed in BW blocks according to a 2 dietary (D) × 2 feeding system (FS) factorial arrangement composed of to 2 diets [control (CN): INRA ideal AA ratio or supplemented (AA+) 120% of the ideal ratio for Met, Thr and Trp] and 2 feeding systems [conventional (GP) or IPF]. GP pigs were fed with a unique diet that matched the SID Lys requirement of the 80th-percentile pig at the beginning of the trial whereas the IPF pigs received a diet tailored daily to each pig requirement. All pigs were housed in the same pen and fed ad libitum during 28 experimental days with automatic feeding stations able to provide to each pig the assigned diet. Body composition was obtained by dual X-ray absorptiometry at days 0 and 28 and blood samples were collected at d 28. Data were analyzed with D and FS and their interaction as main fixed factors and body weight (BW) blocks as a random effect (Table 1). Haptoglobin serum concentration increased from d 0 to 28 regardless of FS and D (P < 0.10). IPF pigs fed with CN diet had the lightest BW at the end of the trial (P ≤ 0.10; FS × D), whereas BW was similar for the other treatments. However, across diets, IPF pigs had final BW, and protein, ADG, G:F, protein and lipid deposition, N intake and excretion and circulating triglycerides that were less than GP pigs. N utilization efficiency was similar across treatments. Additionally, increasing the provision of the studied functional AA did not improve pig performance. Thus, showing no benefits in increasing AA ratios for growth and immune response. The increased triglycerides concentration and low protein and lipid deposition suggests that IPF pigs prioritized the immune system to the expense of protein and lipid accretion. In conclusion, AA supplementation and IPF do not improve growth performance and N efficiency of pigs raised in poor sanitary conditions.

Abstract Great variability in growth performance and blood metabolites is observed between animals and within the same group. This variation may exist between individuals due to the initial body weight (BW) which may determine different abilities to cope with a sanitary challenge (SC). Besides, supplementing tryptophan (Trp), threonine (Thr), and methionine (Met) above NRC requirements supports the immune system and growth performance costs during a SC. Therefore, this study aimed to investigate the effect of initial BW on changes in body composition, and blood metabolites of growing pigs housed under poor SC and receiving Trp, Thr, and Met at 100 or 120% of NRC recommended levels. Twenty gilts were categorized into two groups according to initial BW: light (22.5 ± 0.8 kg) and heavy (28.5 ± 1.0 kg). Both BW groups were group-housed for a 28-d trial. Pigs were orally inoculated with 2 × 109 CFU of Salmonella typhimurium, and manure from a commercial pig farm was spread on the floor. Two dietary treatments were provided: control (CN) or supplemented (AA+) diet with Trp, Thr, and Met:Lysine 20% above the NRC (2012) requirements. Serum albumin and urea, along with BW were measured on days 0, 14, and 28. Body composition was estimated by dual-energy X-ray densitometry on days 0, and 28 to obtain protein (BP, % of BW) and lipid (BL, % of BW) masses. A linear mixed regression considering repeated measures in time was used to compare the slopes of the BW groups, day, and their interaction within dietary treatments. The BW and BP increased, whereas BL decreased with time (P < 0.10; Table 1). However, light pigs had greater BL than heavy pigs (P < 0.10). Dietary treatment influenced BW differently, and BL changes over time within BW groups (Figure 1). Light pigs fed the CN diet had a faster decrease in BL and a slower increase in BW over time than heavy pigs (P < 0.10), which was not observed in pigs fed AA+ diet. Light pigs fed CN diet had greater serum urea than heavy pigs (P < 0.10), with no differences for pigs fed AA+ diet. No changes in serum albumin were observed between BW within diets. Heavier pigs tend to adapt and cope better under a SC and may not need AA supplementation above the requirement. On the other hand, increasing AA improved ability of lighter pigs to cope with the SC allowing for a greater growth potential under a poor SC.

Abstract Feeding behavior is an area of study that links the nutritional and behavioral sciences. However, describing the feeding behavior of pigs is difficult given the diversity of variables available and the large day-to-day intra-animal variation. The objectives of this study were to create an index integrating information from several components of feeding behavior that accounts for intra-animal variation, and to evaluate the capability of this index to study the impact of different feeding strategies in pigs’ feeding behavior. Feed intake information from 160 pigs during the last 28 days of the finishing phase from 3 datasets was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman’s correlations of IIFI with the number of daily meals (r = -0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. Analysis of variance in datasets 1 and 2 showed that moving from conventional to feeding precision systems does not interfere with the feeding behavior of finishing pigs (P > 0.05). In dataset 3, pig feeding behavior was more regular in control diets than for pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola than in pigs fed wheat by-product diets. These results indicate that IIFI integrates information from several components of the feeding behavior of pigs and demonstrates its potential to evaluate the effect of feeding strategies on feeding behavior.

Key messageMaximizing crop yield while at the same time minimizing crop failure for sustainable agriculture requires a better understanding of the impacts of plant breeding on crop genetic diversity. This review identifies knowledge gaps and shows the need for more research into genetic diversity changes under plant breeding.Modern plant breeding has made a profound impact on food production and will continue to play a vital role in world food security. For sustainable agriculture, a compromise should be sought between maximizing crop yield under changing climate and minimizing crop failure under unfavorable conditions. Such a compromise requires better understanding of the impacts of plant breeding on crop genetic diversity. Efforts have been made over the last three decades to assess crop genetic diversity using molecular marker technologies. However, these assessments have revealed some temporal diversity patterns that are largely inconsistent with our perception that modern plant breeding reduces crop genetic diversity. An attempt was made in this review to explain such discrepancies by examining empirical assessments of crop genetic diversity and theoretical investigations of genetic diversity changes over time under artificial selection. It was found that many crop genetic diversity assessments were not designed to assess diversity impacts from specific plant breeding programs, while others were experimentally inadequate and contained technical biases from the sampling of cultivars and genomes. Little attention has been paid to theoretical investigations on crop genetic diversity changes from plant breeding. A computer simulation of five simplified breeding schemes showed the substantial effects of plant breeding on the retention of heterozygosity over generations. It is clear that more efforts are needed to investigate crop genetic diversity in space and time under plant breeding to achieve sustainable crop production.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-015-2585-y) contains supplementary material, which is available to authorized users.