SummaryThree techniques, lamb-suckling and test-weighing, hand- or machine-milking following administration of oxytocin, and measurements of body-water turnover, used for the estimation of milk yield in suckled sheep are discussed in relation to sources of error and comparability of estimates.Results are presented from an experiment in which the lamb-suckling and the oxytocin techniques were compared. The mean daily milk production of Scottish Blackface and East Friesland × Scottish Blackface ewes suckling single and twin lambs was measured by both methods at weekly intervals for 6 weeks. All ewes were well nourished to ensure full expression of milking capacity. Additional information from a similar experiment on Merino ewes is also presented.The oxytocin method gave higher estimates of mean daily milk yield in the first week of lactation, especially in the groups of ewes rearing single lambs and in the Blackface breed. By the second week in most groups and the third week in all groups there were no significant differences between estimates made by the two methods and the relative values of the estimates were not affected by level of milk production, number of lambs suckled or genotype of ewe and lamb.

The concentration (<I>c</I>) of free fatty acids (FFAs) in milk is an indicator of dairy cow nutrition, milk straining, its bacterial contamination and storage quality. High FFA concentrations (<I>cs</I>) caused by lipolysis can damage the quality properties of milk products. Therefore the FFA content is introduced thanks to an increase in the efficiency of modern analytical methods as a milk quality indicator and as an indicator for its price as well. The goal of this paper was to analyse the FFA relations to the other milk quality indicators. The data set (<I>n</I> = 11 586) was evaluated by regression methods. In November and December the respective FFA means were 0.614 ± 0.458 and 0.835 ± 0.491 mmol/100 g with a relatively high variability of 74.6 and 58.8%. The frequency of unsatisfactory FFA values (> 1.3) was 7.51 and 13.93%. Casein content (<I>r</I> = –0.17; <I>P</I> < 0.01) and crude protein content (<I>r</I> = –0.12; <I>P</I> < 0.01) were related more closely with FFA <I>c</I>. The FFAs can increase by 0.066 mmol/100 g with casein decrease by 0.10%. The FFAs in milk fat can slightly increase by the supply of energy to dairy cows (protein and casein decrease) and rise with the deteriorating health state of mammary gland (lactose, <I>r</I> = –0.14; <I>P</I> < 0.01) as well. The somatic cell count correlated with FFAs more weakly (<I>r</I> = 0.07; <I>P</I> < 0.05), similarly like the total mesophilic bacteria count (<I>r</I> = 0.11; <I>P</I> < 0.01), relatively more closely the psychrotrophic bacteria count (<I>r</I> = 0.27; <I>P</I> < 0.05). The deterioration of almost all hygienic indicators signified an FFA c increase. The urea content correlated with FFAs weakly (<I>r</I> = –0.08; <I>P</I> < 0.05) and the fat content imperceptibly as a component of similar substance like FFAs. The mechanical milk stress led to FFA liberation from fat esters proportionally to the intervention intensity (<I>P</I> < 0.001). Even a relatively small mechanical stress caused by mixing comparable to the current milking technology, milk transport and storage increased the FFA c of milk fat from 1.11 ± 0.19 to 1.80 ± 0.40 mmol/100 g (<I>P</I> < 0.05). The highest experimental stress up to 6.88 ± 0.55 mmol/100 g (<I>P</I> < 0.001).

The objectives were to evaluate the effects of sire and content of fresh or ionised egg yolk in extenders on sperm motility and share of live and dead sperm in collected ejaculate, in thawed artificial insemination (AI) doses, and during thermodynamic testing compared to extenders not containing egg yolk. Ejaculates were collected once a week from 4 Holstein bulls. Each of the 20 ejaculate samples from each bull was diluted with 4 different extenders. AndroMed and Bioxcell (no egg yolk) and Triladyl and Optidyl (fresh, ionised egg yolk) were used. A total of 640 AI doses were analysed. The volume of samples, sperm concentration, and percentage of motile spermatozoa were evaluated after collection, as was sperm motility after thawing of AI doses and during thermodynamic testing. Percentages of live and dead sperm were also evaluated. The data set was analysed using SAS/STAT 9.1 (SAS Institute Inc., Cary, NC, USA). The results confirmed significant (P<0.05-0.01) between-sire differences in the volume, density, and activity of sperm as well as in share of live and dead sperm after collection; in decline of sperm motility in the fresh ejaculate, after thawing, and during the entire thermodynamic test, as well as in the share of live and dead sperm after thawing. The extenders ranked by sperm motility are: Optidyl, Triladyl, AndroMed, and Bioxcell, demonstrating the higher quality of AI doses produced using egg yolk extenders. Differences in sperm motility were significant (P<0.05-0.01) during the entirety of thermodynamic testing. Egg yolk extenders had a significantly (P<0.05-0.01) higher percentages of live sperm after thawing.

Dairy cows of 2 breeds, 74 Holstein (H) and 72 Czech Fleckvieh (C) cows in the 1st (H, n=38; C, n=38) and 2nd lactation (H, n=36; C, n=34) during the 1st period (n=74; H, n=40; C, n=34; to 150 days) and the 2nd period of lactation (n=72; H, n=34; C, n=38; above 150 days) were observed. Differences in external and internal proportions of teat closely before (the 1st measurement), immediately after (the 2nd measurement) and 3 h after milking (the 3rd measurement), udder conformation evaluated by linear description, somatic cell count, daily milk yield and the time of milking were evaluated in relation to the effect of breed and period of lactation. The length of the teat canal, area of the teat end, and wall thickness were measured from the axial picture recorded by ultrasound Aloka SSD500 (Aloka Co., Ltd., Tokyo, Japan).Significant interbreed differences were detected in external as well as internal teat proportions (P<0.05-0.001). Relative changes of teat diameter, comparing C and H cows, differed significantly between the 1st and the 3rd measurement (P<0.05). The length of teat increased during milking and didn´t achieve the beginning size during 3 h after milking. Significant diiference in the length of teat between the 2nd measurement and the 3rd measurement was determined in H cows only (P<0.001). The most significant changes of the length of the teat canal and the area of teat were found in both breeds between values measured closely before and immediately after milking (P<0.5-0.001). Wall thickness was strengthen in C cows (+15.6 %) during the 2nd measurement according to the 1st (P<0.05), while difference represented +18 % (P<0.001) in H cows. Non-significantly higher values of external proportions of teat were measured in the 2nd period of lactation except diameter of teat closely before milking. Internal proportions of teat were always significantly higher in the 2nd period of lactation in relation to the 1st period. Prolongation of teat canal by 0.15 cm (P<0.01) closely before, by 0.16 cm (P<0.001) immediately after, and by 0.13 cm (P<0.01) 3 h after milking was measured in the 2nd period of lactation. The area of teat end measured before milking was significantly larger in the 2nd period of lactation (P<0.01). Keywords

The objectives of this study were to determine and evaluate effect of breed, age and body condition score (BCS) on qualitative and quantitative parameters of bull’s ejaculate. In total, 16 Holstein (H) and 15 Czech Fleckvieh (F) bulls were collected in September 2009 and May 2010. Volume of semen samples, sperm concentration and percentage of motile spermatozoa were evaluated immediately after collecting. Sperm motility was also evaluated after diluting and freezing/thawing of AI doses and subsequently during the short-term test of sperm survival. Percentages of live and pathologic sperm before diluting also were evaluated. The data set was analyzed using a generalized linear model in SAS/STAT software. A statistically significant effect of the breed, age and body condition on qualitative and quantitative traits of bull’s sperm were determined (P < 0.05–0.01). Sperm activity after collection, dilution and freezing/thawing had significantly decreasing character.