The use of genetic markers to improve sow productive life and genetic abnormalities

The driving force behind using molecular genetics in livestock selection programs is to improve the profitability of not only the genetic supplier but also their customers using the product. Traditional quantitative genetics have greatly helped the geneticists improve traits with higher heritabilities, but there is still room for advancements, especially in traits that are measured late in life, measured in only one sex, and traits with lower heritabilities. Two such traits that could benefit from the identification and use of molecular markers are genetic defects and sow reproductive life, or the length of time that a sow remains productive in the breeding herd. The studies presented in this dissertation identify current culling reasons of commercial sows, the identification of genetic markers in growth pathways, genetic markers and their associations with sow productive life, and the use of genetic markers to try to isolate the specific genetic defect causing extra digits on pigs.;Analysis of removal reasons for commercial sows revealed that the culling reasons for sows in early parities were for reproductive and locomotive failure, while the main reported reason that sows in more advanced parities were culled was old age. The genetic mapping paper identified single nucleotide polymorphisms (SNPs) in six candidate genes for growth/longevity. These genetic markers were then incorporated with additional markers in research pertaining to genetic markers from growth related pathways and their association with sow productive life. Though no marker suggested that it was causative as none caused an amino acid change, the genetic markers for C-C chemokine receptor 7 (CCR7) and CPT1A showed the clearest and most consistent associations, regardless of analyses attempted, with sow productive life. Additionally, CPT1A and IGFBP1 both were significantly associated with reproductive performance traits such as the total number of pigs born or the number of pigs born alive. The use of molecular genetics to identify the causative mutation pertaining to pigs having extra digits was not as successful. The results presented herein will enhance producers\u27 abilities to increase the financial well being of their operations with reduced financial losses due to genetic defects and poor sow productive life

Examining Phenotypic Structural Traits as Indicators for Reproductive Longevity Success in Sows

The objective of this study was to examine structure and body conformation traits of 494 gilts/sows as a prediction of reproductive longevity in sows. This study focused on specific traits including body length, body depth, front and rear pastern angles, knee angle, and hock angle. The primary method of data collection was based on videos. Still images were pulled from the videos when the sow was standing in a natural stance. The images were analyzed and interpreted objectively with Image J which gives the availability to measure distance and angles given known references in the images. The structural data was analyzed for association with reproductive efficiency including feed intake, wean to estrus interval, weight loss, number born alive, and number of parities achieved. The angle measurements on young sows are not as consistent as older, calmer sows. Front pastern angle was significantly associated with P1 Success at 112 days of age. This trait is critical to early survival before any animals are culled. Angles showed significance or trended toward significance predominately at the early first gestation timepoint. Height at flank at all timepoints is significantly associated with LTNP. Smaller animals have a greater success reaching parity 4 and significant advantages in lifetime reproduction traits compared to the larger animals. As producers are making selections on their replacement gilts, they should avoid selecting the largest females

The effect of varicocele on semen quality in boars exposed to heat stress

Semen quality has a dramatic impact on reproductive efficiency in the swine industry, influencing both conception rate and litter size. The objective of this study was to assess whether the presence of varicocele hinders semen quality in both thermoneutral and heat stress (HS) conditions. At approximately 6 mo of age, ultrasonography was used to measure left and right pampiniform plexus area in order to detect varicocele in maternal line boars at the University of Nebraska–Lincoln. Between 10 and 12 mo of age, semen was collected from each boar (n = 28) twice weekly. Boars were collected under thermoneutral conditions, were then heat stressed for 7 d to exacerbate any semen quality issues, and semen was collected post-HS for 6 wk. Sperm characteristics were determined by computer-assisted semen analysis. The presence of varicocele had a significant effect on sperm concentration (P = 0.04) and trended toward significance for mean sperm head area (P = 0.06) throughout the duration of the study. An interaction existed between varicocele and collection time point at weeks 2–5 post-HS for distal droplet percentage, suggesting that boars with varicocele were possibly more susceptible to heat-stress-induced semen quality issues than boars without varicocele. Moreover, semen quality was reduced in boars with versus without varicocele under both thermoneutral and HS conditions. Therefore, detection of varicocele by ultrasound could represent a potential marker of fertility in young boars or as a component trait in selection indices for fertility

Selection Lines for Residual Feed Intake in Yorkshire Swine

A line of Yorkshire pigs was selected for 3 generations for reduced residual feed intake (RFI), a measure of feed efficiency defined as feed consumed over and above average requirements for maintenance and growth. Heritability estimates of RFI, feed intake, growth, and backfat were 0.30, 0.46, 0.33, and 0.67. Comparison of performance of gilts from the selected line (n=49) to those of a randomly selected control line (n=38) from ~40 to ~70 kg showed that selection had significantly decreased feed intake by 123 g/d. There were no significant differences in average daily gain and backfat between the lines, although the selection line tended to have 22 g/d less growth. In conclusion, RFI is a heritable trait and selection for RFI has significantly decreased the amount of feed required for a given rate of growth and backfat

Identifying Early-Life Behavior to Predict Mothering Ability in Swine Utilizing NU\u3ci\u3etrack\u3c/i\u3e System

Early indicator traits for swine reproduction and longevity support economical selection decision-making. Activity is a key variable impacting a sow’s herd life and productivity. Early-life activities could contribute to farrowing traits including gestation length (GL), number born alive (NBA), and number weaned (NW). Beginning at 20 weeks of age, 480 gilts were video recorded for 7 consecutive days and processed using the NUtrack system. Activity traits included angle rotated (radians), average speed (m/s), distance traveled (m), time spent eating (s), lying lateral (s), lying sternal (s), standing (s), and sitting (s). Final daily activity values were averaged across the period under cameras. Parity one data were collected for all gilts considered. Data were analyzed using linear regression models (R version 4.0.2). GL was significantly impacted by angle rotated (p = 0.03), average speed (p = 0.07), distance traveled (p = 0.05), time spent lying lateral (p = 0.003), and lying sternal (0.02). NBA was significantly impacted by time spent lying lateral (p = 0.01), lying sternal (p = 0.07), and time spent sitting (p = 0.08). NW was significantly impacted by time spent eating (p = 0.09), time spent lying lateral (p = 0.04), and time spent sitting (p = 0.007). This analysis suggests early-life gilt activities are associated with sow productivity traits of importance. Further examination of the link between behaviors compiled utilizing NUtrack and reproductive traits is necessitated to further isolate behavioral differences for potential use in selection decisions

Examining Phenotypic Structural Traits as Indicators for Reproductive Longevity Success in Sows

The objective of this study was to examine structure and body conformation traits of 494 gilts/sows as a prediction of reproductive longevity in sows. This study focused on specific traits including body length, body depth, front and rear pastern angles, knee angle, and hock angle. The primary method of data collection was based on videos. Still images were pulled from the videos when the sow was standing in a natural stance. The images were analyzed and interpreted objectively with Image J which gives the availability to measure distance and angles given known references in the images. The structural data was analyzed for association with reproductive efficiency including feed intake, wean to estrus interval, weight loss, number born alive, and number of parities achieved. The angle measurements on young sows are not as consistent as older, calmer sows. Front pastern angle was significantly associated with P1 Success at 112 days of age. This trait is critical to early survival before any animals are culled. Angles showed significance or trended toward significance predominately at the early first gestation timepoint. Height at flank at all timepoints is significantly associated with LTNP. Smaller animals have a greater success reaching parity 4 and significant advantages in lifetime reproduction traits compared to the larger animals. As producers are making selections on their replacement gilts, they should avoid selecting the largest females

Multi-Pig Part Detection and Association with a Fully-Convolutional Network

Computer vision systems have the potential to provide automated, non-invasive monitoring of livestock animals, however, the lack of public datasets with well-defined targets and evaluation metrics presents a significant challenge for researchers. Consequently, existing solutions often focus on achieving task-specific objectives using relatively small, private datasets. This work introduces a new dataset and method for instance-level detection of multiple pigs in group-housed environments. The method uses a single fully-convolutional neural network to detect the location and orientation of each animal, where both body part locations and pairwise associations are represented in the image space. Accompanying this method is a new dataset containing 2000 annotated images with 24,842 individually annotated pigs from 17 different locations. The proposed method achieves over 99% precision and over 96% recall when detecting pigs in environments previously seen by the network during training. To evaluate the robustness of the trained network, it is also tested on environments and lighting conditions unseen in the training set, where it achieves 91% precision and 67% recall. The dataset is publicly available for download