L. A. Goonewardene

Evaluation of early conception factor lateral flow test to determine nonpregnancy in dairy cattle

The early conception factor (ECF) lateral flow test was evaluated for its ability to accurately determine nonpregnant status in dairy cattle. Results of 2 field trials involving 191 cows and 832 tests indicated the probability that a cow can be correctly diagnosed as nonpregnant by using the ECF test is only about 50%. Agreement of test results between milk and serum obtained from the same cow was 57.5%. The ECF test was not consistent in identifying nonpregnancy when the same cows were tested repeatedly over a period of 4 weeks. We conclude that the ECF lateral flow test does not accurately identify nonpregnancy in dairy cattle.

A study on the prevalence and intensity of occurrence of Thelazia skrjabini (Nematoda: Thelazioidea) in cattle in central Alberta, Canada.

The distribution of Thelazia skrjabini in the eyes of cattle was examined from necropsies on 297 animals. Although the overall prevalence in beef cattle (21.5%) was similar to that in dairy cattle (25.7%), in general worms were more abundant in beef than in dairy animals. The worm prevalence was lowest in the months from March to June and highest in September among beef and dairy animals. Thelazia skrjabini was found in 76 (16.8%) eyes from beef, and 23 (16.4%) eyes from dairy cattle. Infections were not randomly distributed among the eyes of cattle. Significantly more dairy and beef cattle contained T. skrjabini in both eyes than expected based on the observed prevalences. Based on chi-square probabilities, significantly more cattle more than 2 yr of age and less than 10 mo of age were infected with T. skrjabini. Although all age groups were infected, more worms were observed in cattle more than 2 yr of age. More female worms than males were collected from cattle. The male-to-female ratio of 1:2 was consistent regardless of cattle age, season, or type.

Effects of feeding wheat straw and middlings ensiled with whey on digestibility and growth of cattle

Two studies were conducted with the objective of evaluating the effects of feeding different levels of whey ensiled with wheat straw and wheat middlings (whey silage) compared to control diets on production parameters in growing cattle. Whey silage was included in diets at 55 and 65.5% on a dry matter basis with net energy for maintenance and crude protein calculated to be similar to control diets containing a combination of alfalfa hay, corn silage and wheat middlings at 1.74 Mcal kg-1 and 13.4%, respectively. Dry matter intake averaged 8.41 versus 8.91 kg d-1 (P 0.05) in feed efficiency (8.73:1 versus 8.71:1) were observed. However, the higher dry matter intake (DMI) of cattle fed diets wi...