R.H. Miller

Cattle tick vaccine researchers join forces in CATVAC

A meeting sponsored by the Bill & Melinda Gates Foundation was held at the Avanti Hotel, Mohammedia, Morocco, July 14–15, 2015. The meeting resulted in the formation of the Cattle Tick Vaccine Consortium (CATVAC).

Effect of bovine growth hormone on incorporation of [14C]acetate into lipids by co-cultures of bovine mammary, liver, and adipose tissue explants.

Incorporation of [14C]acetate into lipids was measured in 24 hr co-cultures of mammary, liver and adipose tissue from Holstein cows at 53, 210 and 318 d of lactation in the presence or absence of bovine growth hormone. Little (less than 1%) of the labeled lipids appeared in the media relative to that incorporated into the tissue. In mammary tissue, incorporation of [14C]acetate was highest into triglycerides (16,298 cpm/mg mammary tissue), followed by phospholipids (1,887 cpm), free fatty acids (1,252 cpm), diglycerides (708 cpm), free cholesterol (360 cpm) and monoglycerides (93 cpm). Bovine growth hormone did not increase incorporation of [14C]acetate when mammary or adipose tissue were incubated separately. However, in the presence of liver and adipose tissue, bovine growth hormone significantly increased the incorporation of [14C]acetate into triglycerides, diglycerides, free fatty acids and free cholesterol by mammary tissue. These results suggest that bovine growth hormone acts on mammary tissue indirectly through liver and adipose tissue to increase lipid synthesis. This mechanism may play a role in the action of bovine growth hormone in vivo to increase milk and milk fat production.

Impact of genetic merit for milk somatic cell score of sires and maternal grandsires on herd life of their daughters.

A retrospective study of the impact of the estimated breeding values of sires and maternal grandsires for somatic cell score (SCS) on productive life (PL) of Holsteins and Jerseys was conducted. Data included records from 2,626,425 Holstein and 142,725 Jersey cows. The sires and maternal grandsires of cows were required to have been available through artificial insemination and to have predicted transmitting ability (PTA) SCS evaluations based on 35 or more daughters. A weighted function (WPTA) of sire and maternal grandsire PTA for SCS was used: (sire PTA + 0.5 maternal grandsire PTA)/1.5. The 3 dependent variables were PL, frequency of cows culled for mastitis, and first-lactation SCS. The model included effects of herd, birth year, and WPTA (WPTA was categorized into groups: <2.70, 2.70 to 2.79, ..., 3.20 to 3.29, > or =3.30). For analysis of first-lactation SCS, calving year and calving month were substituted for birth year. Differences among WPTA groups were highly significant: as WPTA increased, PL decreased, whereas percentage culled for mastitis and first-lactation SCS increased. The range in PL from lowest to highest WPTA was 5.07 mo for Holsteins and 4.73 mo for Jerseys. Corresponding differences for percentage culled for mastitis were 7.0 and 5.6% and for SCS were 0.95 and 1.04 (for Holsteins and Jerseys, respectively). Although phenotypic studies suggest that cows with extremely low SCS were less resistant to mastitis, our results showed consistent improvements in PL, percentage culled for mastitis, and SCS of daughters when bulls were chosen for low PTA SCS.

Monoclonal antibodies to subpopulations of bovine neutrophils

Monoclonal antibodies were developed to neutrophil surface antigens in an effort to identify neutrophil subpopulations. Eleven monoclonals were positive for neutrophils using the ELISA and flow cytometry. Four monoclonals recognised neutrophils and monocytes, but more importantly each recognised subpopulations of neutrophils. Percentage binding of the same population of neutrophils by each monoclonal was 19H7, 23%; 36H10, 34%; 46B3, 16%; 9D13, 37%. All four showed additive percentage binding to neutrophils when reacted with each other. Cow differences in percentage binding of monoclonals were also evident, i.e., 46B3 — cow no. 8437, 8%; cow no. 2820, 22%. Monocytes showed the most variation, both by cow and by clone within cow, i.e., cow no. 8813, 46B3 = 98% and 9D13 = 6%; clone 19H7, cow no. 8813 = 88% and cow no. 8679 = 2%. Percentage binding to eosinophils was low for all clones except 46B3 which averaged 46%, 5%, 72% and 76% for four cows tested. Percentage binding to lymphocytes tended to be high for all clones across all cows, averaging 62%. Clone 36H10 tended to be the lowest of the clones, averaging 38%. The ability of these clones to identify subpopulations of neutrophils and the significant among cow variation make them useful tools for studying the relationship of different cell-surface antigens to cell function within cow and among cows.