Natural Protective Factors in Bovine Mammary Secretions Following Different Methods of Milk Cessation

Abstract

Bovine mammary secretions were obtained during late lactation and early involution to determine if different methods of milk cessation influenced milk yield, composition, and in vitro growth of coliform mastitis pathogens. Cows (n = 8/group) producing about 13 kg of milk prior to experimentation were dried off by abrupt or intermittent milk cessation. An additional group was dried off by intermittent milk cessation and fed only hay during the last week of lactation. Cows milked intermittently produced significantly less milk during the last week of lactation than cows dried off by abrupt milk cessation. Mammary secretions from cows milked intermittently and fed only hay contained higher concentrations of somatic cells, lactoferrin, immunoglobulin G, and bovine serum albumin, a lower citrate:lactoferrin molar ratio, and were more inhibitory to in vitro growth of Escherichia coli and Klebsiella pneumoniae throughout most of the experimental period than mammary secretions from cows dried off by intermittent or abrupt milk cessation. Few differences in mammary secretion composition or in vitro growth of mastitis pathogens were observed between cows dried off by intermittent or abrupt milk cessation. Data suggest that growth of mastitis pathogens in mammary secretions may be related to natural protective factors, which can be manipulated by different methods of milk cessation.

Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation

“…Hence the prevalence of IMI in the subsequent lactation may be higher in low-producing than in high-producing cows. Substitution of hay for a total mixed ration, in conjunction with once-a-day milking, resulted in a 70% reduction in milk production, higher SCC, higher levels of immunoglobulin G (IgG) and lactoferrin, elevated pH, and greater inhibition of growth of E. coli in vitro (Bushe and Oliver 1987). These data indicate that a decline in milk production associated with dietary change, and reduced frequency of milking, did stimulate involution and enhance immunity.…”

“…This recommendation is presumably based on data showing that cows producing >9 l/cow/day at the end of lactation developed more new infections than cows producing less than this amount (Neave et al 1968), and that reducing feed intake reduced milk production in late lactation (Lacy-Hulbert et al 1999). Reduction in feed intake and intermittent milking have been hypothesised as inducing early involution of the mammary gland and hence shortening the period of high susceptibility to new IMI following the cessation of milking (Bushe and Oliver 1987). Cows producing less milk at drying off (i.e.…”

Effects of continuous lactation and short dry periods on mammary function and animal health

“…There is no information about composition of mammary secretions during the dry period for cows with SDP. It has been reported that marked changes occur in the composition of mammary secretions along with changes in mammary histology during the dry period (Bushe and Oliver, 1987;Sordillo and Nickerson, 1988;Athie et al, 1996). Significant changes in cellular and chemical composition of mammary secretions occur during early, mid and late dry periods.…”

REVIEW ARTICLE: An integrated view on how the management of the dry period length of lactating cows could affect mammary biology and defence

“…To our knowledge, there are no data about composition of mammary secretions during the dry period for cows with SDP, evidence is indirect. Along with changes in mammary histology during the dry period, dramatic changes occur in the composition of mammary secretions (Breau and Oliver, 1985; Bushe and Oliver, 1987; Sordillo and Nickerson, 1988; Athie et al., 1996). Significant changes in cellular and chemical composition of mammary secretions occur during early, mid and late dry period and we hypothesize that modifications of DPL may influence the occurrence of new IMI by altering the composition of mammary secretions during late gestation (Fig.…”