Lecture 28 4/4/25 Flashcards
What are the characteristics of Clostridium perfringens?
-anaerobic spore forming gram-pos. rod
-7 serotypes loosely defined by toxin production
-types C and D are most common in livestock
-produce toxins that cause clinical dz
-associated with overeating dz/pulpy kidney/enterotoxemia
What are the characteristics of Clostridium “transmission”?
-not really transmitted; thought that calves are colonized from birth
-spores persist in environment
-ubiquitous
What are the conditions that can cause Clostridial overgrowth?
-high grain diet, esp. easily fermentable carbs
-stress
-co-infection
-antibiotic therapy
What are the clinical signs of clostridial overgrowth?
-signs that occur in previously healthy calves following a meal or in a cyclic pattern
-peracute to acute onset
-diarrhea that is hemorrhagic
-necrotic enteritis
-colic associated with functional ileus before diarrhea
-neuro signs. including agonal behavior, bellowing, restlessness, tetany, and opisthotonus
-acute death
How is Clostridium diagnosed?
-often based on clinical presentation and signalment
-demonstration of toxin production via ELISA or PCR
-necropsy
What are the necropsy findings with Clostridium overgrowth?
-necrosis of small intestinal mucosa, esp. in jejunum
-intraluminal blood
-peritonitis
-hemorrhagic mesenteric lymph nodes
What is the treatment for Clostridium?
-antibiotics; oral since bacteria is in lumen
-antitoxin
What is the prevention for Clostridium?
-core vaccination
-dietary management; small, frequent feedings
When is establishing an etiologic dx important?
-if it would cause you to change or develop a vx plan
-if there are public health implications
What are the key principles for preventing neonatal diarrhea?
-reduce exposure to pathogens
-ensure adequate colostrum
-boost immunity of mom and/or calf
-biosecurity
What are the best practices for dairy farms to prevent diarrhea?
-clean maternity pens
-deep bedding
-separate cow and calf quickly
-thoroughly clean between deliveries
-clean the udder before collecting colostrum
-use individual calf hutches
-feed youngest to oldest
-meticulously clean feeding utensils
What are the characteristics of group housing on dairy farms?
group housing saves labor but increases contamination and dz risks
-ideal groups are less than 10 calves/group if this method is used
What is the primary cause of failure of passive immunity of beef farms?
dystocia
What are the characteristics of boosting dam immunity?
-increases colostral titers of IgG and IgA
-done 6 and 3 weeks prior to calving
What are the characteristics of boosting calf immunity?
-can be done with vaccines and/or passive antibodies
-must be administered before colostrum feeding
What is provided by colostrum?
-lots of energy
-immunoglobulins
-maternal WBCs
What are the characteristics of colostrum feeding and timing?
-must be done within the first 12 to 24 hours of life
-90% of colostrum must be fed before 6 hours of age
-calves require at least 150 grams of IgG for adequate passive immunity
-less than adequate transfer leads to failure of passive immunity, which has NO clinical signs
Which cells are responsible for the absorption of antibodies in the colostrum?
M cells
What are the colostrum requirements for dairy calves?
-1 gallon of good quality colostrum
-2 feedings
-10% of body weight
How can colostrum quality be measured?
-colostrometer
-brix refractometer
What are the characteristics of colostrum requirements in beef calves?
-less consistency across breeds and individual dams
-assumed that all beef cows produce adequate colostrum
-beef calves should stand and nurse within 2 hours
-calves should take in 5% body weight in colostrum in first 6 hours
Why do dairy cattle have lower quality colostrum?
dairy cattle produce higher volume, which dilutes the colostrum
Why do repeat dams have better colostrum than first time dams?
-they have gone through the process before
-they are older and have had more exposures
What are the impediments to nursing in beef calves?
-dystocia
-hypothermia
-broken legs
-bad mothers
-poor udder conformation
