The objectives of the study were to define the sensitivity and specificity of the California Mastitis Test (CMT) in determining the presence of intramammary infection in postpartum dairy goats and to determine whether antibiotic therapy increased bacteriological cure rate and lowered somatic cell count (SCC) compared with untreated controls. A CMT was performed and milk samples were collected for bacteriology from 211 glands of 106 does between 0 and 10 d after kidding. From a population of 3,239 glands from goats in 4 commercial herds, goats with one or both glands with a CMT score of >1 and from which bacteria were isolated were either assigned to be treated with 3 intramammary infusions at 12-h intervals of 75 mg of sodium ampicillin and 250 mg of sodium cloxacillin (n = 57 glands) or left as untreated controls (n = 49 glands). Milk samples were collected again 14 ± 3 and 21 ± 3 d later for bacteriology and SCC determination. Composite milk yield, goat SCC, length of lactation, and survival data were collected. A partial budget was constructed to assess the cost effectiveness of treatment. At a cut point of greater than trace, the sensitivity, specificity, and positive and negative predictive values of the CMT were 0.74, 0.74, 0.42, and 0.92, respectively. Treatment increased the bacteriological cure rate compared with no treatment [30/57 (53%) vs. 6/49 (12%)], but there was a pathogen by treatment interaction whereby treatment increased cure proportion in glands infected with minor, but not major, pathogens. Treatment reduced the foremilk gland-level SCC [1,595 (95% CI = 1,106-2,300) vs. 3,028 (95% CI = 2,091-4,385) geometric mean (× 1,000) cells/mL] but not the SCC at goat level [1,596 (95% CI = 1,219-2,090) vs. 1,488 (95% CI = 1,132-1,955) geometric mean (× 1,000) cells/mL] compared with no treatment. Milk yield, risk of removal from the herd, and length of lactation were not altered by treatment. Treatment resulted in a loss of NZ$20.39/doe. It was concluded that use of the CMT as a screening test resulted in a higher likelihood of finding a gland that would be infected than selecting a gland at random. Treatment increased bacteriological cure rate and reduced SCC at gland level compared with no treatment. However, at goat level, milk yield, SCC, and survival were not altered, resulting in no economic benefit of treatment.

Reduction of BTSCC in dairy goats may be best achieved by minimising the prevalence and incidence of new IMI in early lactation. Further studies are required to define management factors associated with the between herd, and stage of lactation, effects on prevalence and incidence rate in order to reduce BTSCC throughout lactation.

SUMMARYFive primiparous and five multiparous cows were used to determine if mammary cisternal storage of milk during a 24 h period of milk accumulation limited milk secretion. In addition, we investigated if there is a parity effect for the capacity of the mammary cisternal compartment to hold a 24 h accumulation of milk secretion, and studied the movement of milk from the alveolar compartment into the cisternal compartment. All cows were fitted with catheters in all teats in order to collect cisternal and alveolar milk fractions separately. For a 24 h period of milk accumulation, the milk was drained once (after 24 h) from one side of the udder (OD), and continuously from the other side of the udder (CD). There was no significant parity effect for cisternal, alveolar and total milk volumes at 24 h. Therefore, data from primi-and multiparous cows were pooled for subsequent analyses. Cisternal milk volume from CD glands was higher than that from OD glands (P < 0.01), indicating that cisternal storage of milk in the mammary gland may be limiting to milk secretion during 24 h milking intervals. Alveolar volumes did not differ between OD and CD, but, as a result of the higher cisternal milk volume, total milk volume was highest in the CD glands (P = 0.05). Movement of milk from the alveolar into the cisternal compartment was intermittent. Moreover, analyses of the slopes of individual milk accumulation profiles of the first 6 h of accumulation revealed that the cisternal compartment starts filling immediately following milking, although the rate of filling is relatively low until 7-8 h postmilking.

SUMMARYHuman synthetic parathyroid hormone-related protein (PTHrP) increased mammary blood flow (MBF) following close-arterial infusion via the external pudic artery in goats during midlactation. MBF increased 74 + 8 % within 30 min of the start of continuous infusion of PTHrP compared with 10 + 3 % in controls. MBF decreased by 90 min, however, and was not different from control values for the remainder of the infusion. The increase in plasma concentrations of calcium and decrease in phosphate during PTHrP suggests that this was not due to altered activity of PTHrP, but may relate to downregulation of response or production of counterregulatory vasoconstnctive agents within the gland. This problem was alleviated when PTHrP was infused in a pulsatile fashion. An average 14-40 % increase in MBF was achieved over 6 h, but this did not alter the rate of milk secretion, suggesting that mammary hyperaemia is not sufficient by itself to increase milk yield in the normally lactating goat. MBF increased in a dosedependent fashion, although the lowest dose used to give a detectable response was approximately 40-fold higher than the concentration normally present in the mammary venous circulation. Thus, endogenous PTHrP may not be an important regulator of MBF during lactation in the goat.

Summary. Studies were undertaken to characterize ihe changes in the milk composition which occur 5-6 days before and 6-7 days after ovulation in lactating women. The composition of the milk at these times was compared to that from women with an acute inflammation (mastitis) in the breast to clarify the nature of the mechanism which caused the change in milk composition during the ovulatory menstrual cycle.The composition of breast milk taken from 2 women from days -8 to -3 and days 4 to 9, relative to the day of ovuiation, showed significant (p < 0-05) increases in Na and Cl and a decrease in glucose. The concentration of albumin and total protein in the milk was unchanged. In contrast, the milk composition from 3 women who developed an inflammation in the one breast during lactational amenorrhea showed significant Ip < 0 05) increases in the concentrations of Na, Cl, total protein and albumin in the milk from the affected breast as compared to the normal breast. The concentration of glucose was not significantly altered.The differences between the composition of milk during the menstrual cycle and during acute breast inflammation are exemplified by a further woman who developed an inflammation in the right breast only on day 7 after ovulation, which coincided with the posl-ovutatory change in milk composition. The concentration of albumin in the milk from the affected breast was significantly (p < 001) increased during the period of inflammation, while it remained stable in the milk from the normal breast. The other constituents showed the normal alterations associated with the lutea! phase of the cycle.While the changes in the concentralions of the ions and albumin in the milk from the affected breast are consistent with the existence of a paracellular pathway between the cells, the changes during the menstrual cycle are not. It is suggested that the milk compositional changes which occur during the cycle are caused by a decrease in the mammary uptake of glucose, with a subsequent reduction in the synthetic activity of the gland. INTRODUCTIONTwo acute changes in the milk composition were observed during the ovulatory menstrual cycle of women (Hartmann and Prosser, 1982). The first change occurred 5-6 days before ovulation and the second 6-7 days after ovulation. The alteration in milk composition was characterized by an