Thermal Profiles: Novel phenotypic measurements of animal growth and metabolic efficiency.

The costs of production for high density protein and the impacts food production have on the environment are becoming increasingly important issues in animal agriculture. The objective of the present study was to investigate the use of novel thermal profiles including a Thermal Efficiency Index (TEI) on the ability to identify efficient animals in a fraction of the time and at a significantly lower cost of conventional feed station and performance technology. Three hundred and fourty four high performance Duroc sires from a genetic nucleus herd were used in the study. The animals were monitored for feed consumption and growth performance using conventional feed station technology for a 72 day period. Animals were monitored in these stations between approximately 50 kg and 130 kg live body weight. An infrared thermal scan was performed on the animals at the end of the performance test by collecting automated dorsal thermal images and using these biometrics to measure both bio-surveillance values and a thermal phenotypic profile including the TEI (mean dorsal temperature /body weight 0.75). The thermal profile values were significantly correlated (r = 0.40, P < 0.0001) with a current industry best practice for performance in Residual Intake and Gain (RIG). The data from the current study suggest these rapid, real time, cost effective values for TEI constitute a useful precision farming tool for the animal industries to reduce the cost of production and green house gas (GHG) impact for high density protein production.

The influence of litter birth weight phenotype on embryonic and placental development at day 30 of gestation in multiparous purebred Large White sows.

The aim of this study was to understand the intrauterine biological processes associated with the low litter birth weight phenotype in pigs. Analyses were conducted on reproductive data from a purebred Large White maternal line to identify sows (>2 parities) with repeatable high or low litter birth weight phenotype (HLBWP or LLBWP). A total of 40 sows were selected (n = 20 HLBWP and n = 20 LLBWP) and bred with semen from purebred Large White boars of proven fertility. Sows were euthanized on day 28-30 of gestation (day 29.5 ± 0.6) and samples of placenta and embryos collected. Total number of embryos (TNE), embryonic weight (EW), embryonic viability, and crown-rump (CRL) measurements were recorded, along with the ovulation rate (OR) and allantochorionic fluid volume (AFV). No significant difference was detected (P > 0.05) in OR, TNE, and number of viable embryos on day 30 of gestation between the two groups. There was no significant difference in EW (LLBWP: 0.80 ± 0.05 g; HLBWP: 0.88 ± 0.04 g, P = 0.18) or CRL (LLBWP: 21.5 ± 0.7 mm; HLBWP: 21.9 ± 0.68 mm, P = 0.46). Placental development represented by the average AFV was significantly lower in the LLBWP compared to HLBWP (LLBWP: 131 ± 9.82 mL; HLBWP: 149 ± 9.39 mL, P = 0.03). In conclusion, placental development may be the main factor causing lower BW of entire litters in LLBWP sows.

Differences in body condition of gilts that are maintained from mating to the end of gestation affect mammary development.

The goal of this project was to determine if different body conditions in late gestation that are due to varying body conditions at mating affect mammary development and mammary gene expression of gilts. Gilts that were fed ad libitum in the growing period were selected based on their backfat depths to form 3 groups at mating, namely, low backfat (LBF; 12-15 mm; = 14), medium backfat (MBF; 17-19 mm; = 15), and high backfat (HBF; 22-26 mm; = 16). During gestation, LBF, MBF, and HBF gilts were fed approximately 1.25, 1.43, and 1.63 times maintenance requirements to maintain their differences in body condition. Feed intake was increased by 1 kg in the last 10 d of gestation. Backfat depths of gilts were ultrasonically measured at mating and on d 30, 50, 70, 100, and 109 of gestation. Blood samples were obtained at mating and on d 109 of gestation to measure concentrations of IGF-1, glucose, insulin, estradiol, urea, free fatty acids, leptin, and adiponectin. Gilts were slaughtered on d 110 of gestation to collect mammary glands for compositional analyses. Mammary extraparenchymal tissue weight was lesser in LBF and MBF gilts than in HBF gilts (1,259.3, 1,402.7, and 1,951.5 ± 70.4 g, respectively; < 0.01). The weight of parenchymal tissue was not affected by treatment ( > 0.10), but its composition was altered. Concentrations of DNA and RNA decreased as backfat depth increased ( < 0.05), whereas percent fat and DM increased ( < 0.05). Circulating concentrations of leptin tended to be lower at mating ( < 0.10) and were lower on d 109 of gestation ( < 0.05) in LBF gilts than in HBF gilts. On d 109 of gestation, concentrations of insulin ( < 0.01) and IGF-1 ( < 0.05) were lower in LBF and MBF gilts than in HBF gilts, whereas those of urea were greater ( < 0.05). The mRNA abundance in parenchymal tissue for all genes studied was not affected by treatments ( > 0.10) with the exception of , which had a greater expression level in LBF gilts than in MFB or HBF gilts ( < 0.05). Percent of Ki-67-positive cells, used to assess mammary cell proliferation rate, was greater in HBF gilts than in LBF gilts ( < 0.05). When differences in body conditions of gilts that were present at mating were maintained throughout gestation, it had an impact on mammary development. Extraparenchymal tissue mass was affected and, more importantly, composition of parenchymal tissue was altered, indicating a beneficial effect of gilts being in the thinner treatment groups at mating.

Genetic and phenotypic parameters for carcass and meat quality traits in commercial crossbred pigs.

Pork quality and carcass characteristics are now being integrated into swine breeding objectives because of their economic value. Understanding the genetic basis for these traits is necessary for this to be accomplished. The objective of this study was to estimate phenotypic and genetic parameters for carcass and meat quality traits in 2 Canadian swine populations. Data from a genomic selection study aimed at improving meat quality with a mating system involving hybrid Landrace × Large White and Duroc pigs were used to estimate heritabilities and phenotypic and genetic correlations among them. Data on 2,100 commercial crossbred pigs for meat quality and carcass traits were recorded with pedigrees compromising 9,439 animals over 15 generations. Significant fixed effects (company, sex, and slaughter batch), covariates (cold carcass weight and slaughter age), and random additive and common litter effects were fitted in the models. A series of pairwise bivariate analyses were implemented in ASReml to estimate phenotypic and genetic parameters. Heritability estimates (±SE) for carcass traits were moderate to high and ranged from 0.22 ± 0.08 for longissimus dorsi muscle area to 0.63 ± 0.04 for trimmed ham weight, except for firmness, which was low. Heritability estimates (±SE) for meat quality traits varied from 0.10 ± 0.04 to 0.39 ± 0.06 for the Minolta b* of ham quadriceps femoris muscle and shear force, respectively. Generally, most of the genetic correlations were significant (P < 0.05) and ranged from low (0.18 ± 0.07) to high (-0.97 ± 0.35). There were high negative genetic correlations between drip loss with pH and shear force and a positive correlation with cooking loss. Genetic correlations between carcass weight (both hot and cold) with carcass marbling were highly positive. It was concluded that selection for increasing primal and subprimal cut weights with better pork quality may be possible. Furthermore, the use of pH is confirmed as an indicator for pork water-holding capacity and cooking loss. The heritabilities of carcass and pork quality traits indicated that they can be improved using traditional breeding methods and genomic selection, respectively. The estimated genetic parameters for carcass and meat quality traits can be incorporated into the breeding programs that emphasize product quality in these Canadian swine populations.