The effects of vacuum level and overmilking on udder health were studied in ewes. Vacuum levels of 36 and 42 kPa were assigned to two groups of 23 Manchega ewes in a crossover study design with two experimental periods of 5 wk for each. Moreover, for each ewe, one teat was overmilked 1.5 to 2 min at all milkings during these 10 wk. The milking machine used had a midlevel milkline and pulsation was fixed at 180 cycles per min and a pulsation ratio of 50:50. Bacterial exposure of all teats was increased by dipping them in a suspension of Staphylococcus simulans at eight milkings of each period. New intramammary infections (IMI) were not significantly affected by the vacuum level used (18 and 23% of ewes infected, at 36 and 42 kPa, respectively) or application of overmilking (9 and 11% of half udders infected without and with overmilking, respectively). Likewise, neither factor significantly affected the somatic cell count (SCC) of the milk. Teat thickness changes after milking varied significantly due to the presence of overmilking (-13.6 and -7.4%, in teats not overmilked and overmilked, respectively) but were not affected by vacuum level. At no time were any lesions or variations visibly noted in the teat walls or orifice. So, in this work we were unable to demonstrate that the vacuum and overmilking levels assayed, both used with a pulsation rate of 180 cycles/min, have an important effect on the state of udder health in the short term. Furthermore, it was also observed that, in absence of IMI, the two factors studied did not cause irritation of any kind in the gland that might influence the SCC of the milk.

Two experiments were carried out to compare mechanical milking in mid-level (ML) and low-level (LL) milkline in goats. The first trial used 40 intramammary infection (IMI)-free goats that had been milked in ML during a pre-experimental period of 4±1 weeks post partum. These animals were divided into two groups (n=20), randomly assigning each group to ML or LL milking for a 17-week experimental period. During this period, several strategies were applied to increase teat exposure to pathogens in both experimental groups. The IMI rate was the same in both experimental groups (30% of goats), although the majority of new infections appeared earlier in ML (weeks 1–5) than in LL (weeks 7–16). Teat-end vacuum range (maximum minus minimum vacuum) was higher in ML than in LL, but no significant differences were found in the remaining variables [milk production and composition, somatic cell count (SCC), frequency of liner slips+teatcups fall off]. In the second experiment, in a crossover design (54 goats in fourth month of lactation; 2 treatments, ML and LL, in 2 experimental periods each lasting 1 week) it was observed that both the milk fractioning (reduced machine milk and increased machine stripping) and average machine milk flow worsened slightly in ML milking; in contrast, no differences were observed in total milking time or teat thickness changes after milking. It was concluded that the differences found between ML and LL are not sufficiently important to discourage breeders from using ML in goat milking.

In this work on machine milking of ewes, pulsation rates of 120 and 180 cycles per min were compared, both with a pulsation ratio of 50:50 and a vacuum level of 36 kPa, comparing intramammary infection (IMI), somatic cell count (SCC) and teat end thickness changes. To this end, two groups of 20 Manchega ewes were used in a crossover experimental design with two experimental periods of 24 d for each. Bacterial exposure of all teats was increased by dipping them in a suspension of Staphylococcus simulans at four consecutive milkings of each period. Pulsation rate of 180 cycles per min, compared with 120 cycles per min, had no negative effect upon new IMI (11 and 16% of ewes infected, respectively) and SCC. No teat end lesions were observed in those animals milked with the two pulsations assayed. Also, teat thickness changes (-0.38 and -0.36 mm at 120 and 180 cycles per min, respectively) were not affected significantly. Finally, in absence of IMI, the two pulsation rates assayed did not affect the SCC.

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 (TO) was 4.9 s and at the milk meter (T1) was 15.8 s. Average milk flow after 30 s (MF0.5) was 0.29 kg/30 s (0 to 1.1 kg/30 s) and milk flow at 60 s or milking speed (MF1) was 0.67 kg/min (0.1 to 2.1 kg/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 with T1 (-0.63) and MF0.5 (0.90), medium values with T0 (-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 3 mo (0.67-0.71 kg/ min) and decreasing until the end of lactation (0.58 kg/ 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.

The aim of this work was to improve the growth characteristics of Murciano-Granadina (MG) kids through terminal crossbreeding of MG goats to Boer bucks. Four experiments were carried out, using a total of 354 MG goats, half of which were mated with MG bucks (n = 12) and the other half with Boer bucks (n = 12). The kids were raised in artificial rearing until slaughter weight (9 kg). The birth weight and average daily gain were recorded in crossed kids (n = 197 and 145, respectively) and purebred kids (n = 257 and 169, respectively). Crossed kids presented significant differences (p < 0.001) compared to MG purebred kids in birth weight (+ 24%), mortality in artificial rearing (−37%), average daily gain (+32%) and milk powder conversion rate (−16%). However, the reproductive performance rates of MG goats mated with Boer bucks were slightly worse (pregnancy rate: 78.5% vs. 86.6%, p < 0.05; kidding rate: 62.0% vs. 75.7%; p < 0.01; prolificacy: 1.9 vs. 2.1 kids/parturition), especially when the matings took place in non-breeding season (experiments conducted at latitude 38–39° N). It is concluded that the terminal crossbreeding of MG goats to Boer bucks (those not used to produce replacement kids) could be an interesting option for ethical goat production.