A study was conducted to evaluate effects of housing and feeding systems on performance of neo-natal Holstein bull calves. Treatments included individually housed, bottle-fed (n = 5 calves), individually housed, bucket-fed (n = 5 calves), group housed bottle fed (n = 5 pens) and group housed bucket fed (n = 5 pens). Body weights were collected every 7 days and serum and plasma samples were taken on day 0, 28, 55 and 66 for beta-Hydroxybutyrate concentrations. No major differences (P > 0.11) in performance (average daily gain, dry matter intake, and feed efficiency) or β-Hydroxybutyrate (P > 0.14) concentrations were observed between housing and feeding treatments. Likewise, no differences (P > 0.26) were observed in the coefficient of variation for BW or fecal scores or morbidity. Albeit performance wasn’t altered, group housing provides a social environment and bucket feeding lowers the variation of intake amongst the group.

Efficacy of a sustained-release formulation of bST was evaluated for two consecutive lactations. Response in milk and milk component yield was positive and very consistent for multiparous cows between lactations. Average responses in milk production for the first lactation and for the 320-, 640-, and 960-mg$ cdot$28d$ sp{-1}$ doses of bST were 4.3, 5.2 and 5.9 kg$ cdot$d$ sp{-1}$, respectively. Response was 4.9 kg$ cdot$d$ sp{-1}$ for the average of the second lactation with 640 mg bST$ cdot$28d$ sp{-1}$. Primiparous cows responded with the same numerical magnitude as multiparous cows but with higher variability. BST caused a response in milk yield irrespective of the stage of lactation when injections commenced, but the magnitude of response was greater at latter stages of lactation. No adverse effect of treatment on final body condition score and achievement of proper condition for a subsequent lactation was found. No effect of treatment was observed on health parameters in either lactation. Trends towards longer days open and more breedings per conception were apparent for both lactations. Total milk protein, caseins and whey proteins were not changed at any stage of lactation and for the average of the full lactation. BST did not significantly change proportions of $ alpha sb{s}$-, $ beta$- and K-caseins. Milk fat percentage and milk fatty acid profiles were not different between control and any dose level of bST for a complete lactation. Maximum response in milk yield for the different doses of bST was from d8 to 12 of the 28d cycle and was almost eliminated by d22 to 24. A 3.1 and 3.6 kg$ cdot$d$ sp{-1}$ milk augmentation with bST was estimated in cows infused for 6d with glucose and saline, respectively during peak lactation. There was no apparent milk yield response when cows were infused with insulin + glucose but cows exhibited positive energy balance, weight gain and only 5% less milk. Insulin + glucose infusion increased milk protein 11% and 14% compa

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Although the perifornical lateral hypothalamic area (PeFLH), which contains orexin/hypocretin (OX) neurons, plays an important role in arousal-related behaviors, its neuromodulatory inputs are incompletely understood. The present study examined the role of glutamatergic inputs to the PeFLH in various arousal-related behaviors. Adult male rats received a microinjection of the ionotropic glutamate receptor agonists AMPA (1 and 2 mM) or NMDA (1 and 10 mM), or vehicle into the PeFLH, and were placed in an open field; 90 min later, rats were perfused for immunohistochemistry for OX and c-Fos as a marker of neuronal activation. AMPA injections dose-dependently increased locomotion, rearing, and drinking. NMDA injections (at 10 mM) increased locomotion and feeding. All these behaviors (except feeding) were positively correlated with the number of c-Fos/OX-immunoreactive neurons. These results support the role of ionotropic glutamate receptors on OX (and other) neurons in the PeFLH in the regulation of locomotor and ingestive behaviors.

I examined the suspension feeding of four freshwater unionid mussels, Elliptio complanata, Elliptio dilatata, Fusconaia flava and Strophitus undulatus to help explain how more than 30 species can coexist in a single river, as well as to contribute new insights into their basic biology. I examined whether the flux of algae affected the suspension feeding (clearance rate, CR) of unionids in a flow chamber. CR varied with seston flux (J = UC, where U is the velocity and C is the algal concentration) for the 4 species examined. The lotic species (E. dilatata) cleared up to four times more water than lentic species (E. complanata). Differences in CRs were found among E. dilatata, F. flava, and S. undulatus from the same hydrodynamic habitat at the highest flux tested; the CR of E. dilatata varied with the hydrodynamics of its native river. These results provide new insight into how seston flux influences unionid suspension feeding, which may help to explain niche breadth in this group.

The objective of this thesis was to determine the effect of housing and feeding management and cow characteristics on the behavioral patterns of cows in automated milking systems (AMS). In a first study, increasing frequency of feed delivery from 1 to 2x/d for cows milked in an AMS resulted in longer lying duration. In that study, lame cows milked less frequently, had increased lying durations and more frequent lying bouts. In a second, cross-sectional study of 13 AMS farms it was found that cows had longer lying durations when given more space at the feed bunk and when their feed was pushed up more frequently. Milking frequency increased as cows/AMS decreased. Milk yield increased with space at the feed bunk. Overall, these results suggest that feeding management, robot and bunk-space availability, and health status affect the behavior and production of AMS-milked cows. / Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and the Canadian Bovine Mastitis Research Network (CBMRN)

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