Udder Health for Dairy Goats

Staphylococcus aureus is the most important cause of clinical mastitis in goats, and non-aureus staphylococci is the most common isolate from subclinical mastitis. Environmental streptococci are a severe problem. Somatic cell counts and California mastitis test are a screening test for mastitis and an indicator of poor udder health, but values should be interpreted differently than with dairy cattle. Somatic cell scores likely are a more useful way of viewing data. High bacterial counts in milk are common; mastitis may be involved as a cause. Proper udder preparation, milking procedure, and postmilking management are key factors in mastitis control.

Effect of stress on somatic cell count and milk yield and composition in goats

There is little information about the effect of the stress on Somatic Cell Count (SCC) and milk yield and composition in goats. A total of 40 goats in their 4th month of lactation were assigned to two groups: stress (STR) and untreated (CON). Goats of STR were exposed to acute stress (visual and auditory stimulus from a barking dog for 20 min on day 0). After the stress, average values of plasma cortisol were higher in STR than CON (P < 0.001); likewise, in STR group cortisol was lower in parity 1 + 2 goats than parity ≥3 goats (P < 0.05). Stress caused a considerable increase in SCC in parity ≥3 goats (P < 0.05), but not in parity 1 + 2 goats. On average, this increase of SCC was 6-fold compared to values prior to the stress, and it was observed in both healthy and infected mammary glands. This increase was transient, as SCC returned to normal values after 1 to 3 days. On day 1, stressed goats of parity ≥3 produced 11% less milk compared with day 0 and, regarding milk composition, only lactose showed a significant drop. Stressed parity 1 + 2 goats showed no changes in SCC and milk yield and composition. We conclude that, in goats, stress is a non-infectious factor that can interfere in the use of SCC as an indirect method of intramammary infection (IMI) detection or, in bulk tank milk, as a commercial milk quality parameter.

Factors affecting milking speed in Murciano-Granadina breed goats

Milk flow during the first minute of milking was analyzed using data from 1,132 Murciano-Granadina breed goats belonging to 17 herds. During the individual lactations, 2 test days were scheduled for recording several milk flow traits, total milk, milk composition (fat and protein percentages), and somatic cell count. Average lag time from teatcup attachment to arrival of milk at the milk claw (T0) was 4.9 s and at the milk meter (T1) was 15.8 s. Average milk flow after 30 s (MF0.5) was 0.29kg/30 s (0 to 1.1kg/30 s) and milk flow at 60 s or milking speed (MF1) was 0.67kg/min (0.1 to 2.1kg/min). Repeatabilities of T0, T1, MF0.5, and MF1 were 0.45, 0.58, 0.62, and 0.68, respectively. The MF1 showed high phenotypic correlation withT1(-0.63) and MF0.5 (0.90), medium values withT0(-0.42) and total milk (0.22), and very low values (-0.04 to -0.12) with fat, protein, and somatic cell count. We found no differences between flows during the first 3 lactations, with a reduction as the lactation number increased. Months in milk since parturition affected MF1, being highest in the first 3mo (0.67-0.71kg/min) and decreasing until the end of lactation (0.58kg/min). The effect of herd-test day was significant for all traits. Inclusion of all these effects for the analysis of milk flow traits is considered necessary.