BOVINE RESP

Question 1

An 8 week old Beefmaster calf presents with a 2 day history of rapid and labored respiration, depression, salivation, nasal and ocular discharge, and a “honking” cough. On physical exam, there are no signs of sepsis, but the calf is tachypneic, dyspneic and febrile. Crackles are audible throughout the lung fields. What is your top differential?

Answer 1

The correct answer is bovine respiratory syncytial virus. The key to being able to make this your top differential is noting that the calf has a “honking” cough, dyspnea, and tachypnea, that the calf is not septic. Pulmonary lesions include severe edema and emphysema. Treatment is usually supportive and antibiotics are given to protect from secondary bacterial infection. Mannheimia hemolytica is the main culprit in shipping fever, and Haemophilus pleuropneumoniae is an occasional cause of shipping fever in cattle. Pasteurella multocida can be a secondary invader in any bovine pneumonia. P multocida also causes the most economic loss in swine with atrophic rhinitis.

Question 2

8 month old calf in a feedlot has a 2 day hx of loud inspiratory stridor and a wet cough. Fetid breath mucopurlent nasal discharge and hyper salivation. Dx

Answer 2

calf diphtheria aka necrotic laryngitis; common in older feedlot cattle (6-18 months)

Question 3

What presents with oculo-nasal discharge, RED-NOSE, and conjunctivitis?

Answer 3

Bovine Herpesvirus 1

Infectious bovine rhinotracheitis virus, Infectious pustular vulvovaginitis, and associated diseases

Question 4

A 4-year old dairy cow in her third lactation presents after calving normally about 95 days ago. No one has observed her in estrus since calving. On physical exam, you find a non-pregnant heavy, fluid-filled uterus, and an apparent corpus luteum on one ovary. Assuming treatment is successful, which of the following is the most significant therapeutic effect of a single intra-muscular injection of PGF2-alpha in this patient?

Answer 4

PGF2-alpha has many effects, but chief among them is its luteolytic action. Lysis of the corpus luteum will immediately reduce circulating progesterone levels, allow the final development of an ovarian follicle, and bring the cow into estrus, which is accompanied by increased uterine motility, and in this case, drainage.

PGF2-alpha will not likely stimulate the cow’s appetite and would not do so by a direct therapeutic effect.

PGF2-alpha will not decrease uterine contractility. PGF2-alpha will probably increase uterine contractility, both directly (utero-tonic effects) and indirectly, through the rise of estrogen that follows PGF2-alpha-induced luteolysis.

PGF2-alpha is an inflammatory mediator. It will NOT directly suppress uterine inflammation. This cow needs an effective immune/inflammatory response to “clean up” her uterus. Anti-inflammatory therapy is not indicated.

PGF2-alpha will NOT cause the maturation and ovulation of multiple follicles (i.e., superovulation). That is achieved by an altogether different class of hormones, the gonadotropins.