Past Events

Welcome back, and happy new year! I would like to invite you to attend the January Installment of the 2022 ‘Virtual’ Nutrition Seminar Series hosted by the Centre for Nutrition Modelling (Animal Biosciences Department). Each month in 2022 we will continue to deliver seminars from a different lab within the Nutrition group, and share their exciting new research in a dynamic virtual manner. Please feel free to forward these seminar invites to industry partners or others outside the department who may be interested.   In January we bring you:

The prevalence of meat quality defects, such as pale, soft, exudative (PSE) meat, and muscle myopathies, such as white striping (WS), have been of increasing interest to the poultry industry over the past few decades. The rise in prevalence of quality defects and myopathies are thought to be closely associated with the drastic changes in growth rate due to improvements in management, nutrition, and genetic selection.

Milk replacers (MR) formulated to contain more lactose than whole milk could potentially reduce insulin sensitivity and gut barrier function in dairy calves. Three studies were conducted to characterize the impact of fat, protein and lactose content, and the fatty acid composition, of MR on glucose-insulin kinetics, gastrointestinal tract (GIT) growth and func-tion. In the first study, thirty-four calves were fed either a high lactose (HL; 46.1%DM lactose) or a high fat (HF; 24.6%DM crude fat) MR during the first week of life.

Reproductive inefficiency is one of the main reasons for culling in both the dairy and beef industry, with pregnancy losses being a contributing factor. Most pregnancy losses occur early after fertilization which may be due to reduced cow and/or bull fertility.  Cattle fertility is a complex trait affected by many physiological events that genomic selection fails to account for, including a non-receptive uterine environment or inadequate semen quality. By identifying highly fertile animals, production efficiency in the cattle industry can be maintained.

Cup plant (Silphium perfoliatum Sp.) is characterized by high biomass yields and the ability to grow on mar-ginal lands where common dairy forage sources are unable to thrive. The objective of this research was to as-sess its feeding value for dairy cows by comparative evaluations of DM degradability in vitro and in situ, and lactational performance in vivo when fed in partial replacement (13% of ration DM) of corn and alfalfa silag-es. In vitro results showed that cup plant silage only had lower DMD than the alfalfa silages, and lower pH than corn silage.

Johne’s disease is a chronic wasting disease in dairy cattle caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP). Genetic selection can help to control this disease, and one candidate gene of interest is the gene encoding for interleukin-10 receptor subunit alpha (IL10Rα). A bovine mammary epithelial cell line was created with the gene encoding IL10Rα knocked out (IL10KO). This cell line was ex-posed to live MAP, and mRNA was extracted. The differentially expressed genes were compared between the IL10KO and wild-type cell lines, and gene ontology was performed.

Mastitis is a very challenging disease in the dairy industry that affects the animal’s health, as well as the producer’s profit and management. Although it has been studied in depth over the years, we have still yet to eliminate it due to the fact that there are numerous pathogens that can cause a mastitis infection, and they are extremely prevalent in the cow’s environment. For this reason, emphasis is being placed on identifying cows that are more able to prevent or recover from a mastitis infection based on her genetics.

Research into the genetic aspects of calf health traits is an emerging field for the dairy industry. Calf respiratory illness and diarrhea remain the two highest causes of calf morbidity and mortality in Canada and worldwide. Previous research has shown there are long term effects to an animal as a result of calfhood morbidity. The goal of the research described in this thesis was to understand the quantity and quality of calf health information available, specifically respiratory illness and diarrhea, that could be used in future genetic research.

Due to the high prevalence of gastrointestinal diseases and disorders in dairy calves, optimizing nutritional strategies to enhance gastrointestinal (GIT) development and improve calf health is at the forefront of industry concerns. This thesis investigates the effects of whole milk powder (WP) and milk replacer (MR) of similar macronutrient composition on GIT development, function, and composition in male Holstein calves.