Short communication: effects of milk removal on teat tissue and recovery in Murciano-Granadina goats

Optimal Parameters to Milk Murciano-Granadina Goats in Mid and Low-Line Milking Parlours

Recent short-term studies on Murciano-Granadina goats have established that the optimal parameters to set up the milking machines are different according to the milk pipes height. Two groups of 52 fresh goats each were employed in 2 different experiments to confirm during an entire lactation period the best combinations of system vacuum pulsation rate and pulsator ratio in low-line and mid-line milking parlours. The experiment performed in the low-line milking parlour included one group milked with 40 KPa vacuum system level, 90 puls/min pulsation rate and 60/40 pulsation and a second group milked with 38 KPa vacuum system level, 90 puls/min pulsation rate and 60/40 pulsation ratio. The experiment carried out in mid-line included one group milked with 40 KPa vacuum system level, 90 puls/min pulsation rate and 60/40 pulsation ratio and a second group milked with 40 KPa vacuum system level, 120 puls/min pulsation rate and 60/40 pulsation ratio. Variables studied included milking efficiency, milk composition, cortisol, SCC and intramammary infections, teat-end oedema after milking and vacuum dynamics during milking. Considering the results of an entire lactation period, it was confirmed that when milking in mid-line, the combination of 40 KPa system vacuum, 90 cycles/min pulsation rate and 60/40 pulsator ratio showed optimal results of the above-mentioned variables. On the other hand, the use of 40 KPa in a low-line system increased the milk cortisol values (0.34 ± 0.1 vs. 0.44 ± 0.1 ng/mL) without any other advantage. Thus, the recommendation is to use a combination of 38 KPa system vacuum, 90 cycles/min pulsation rate and 60/40 pulsator ratio to enhance animal welfare.

Effect of Vacuum Level and Pulsation Parameters on Milking Efficiency and Animal Welfare of Murciano-Granadina Goats Milked in Mid-Line and Low-Line Milking Machines

Simple Summary

In recent years, several studies have been carried out to optimize milking efficiency in Murciano-Granadina goats, but to our knowledge there are no experiments combining different milking parameters (system vacuum, pulsation rate and pulsator ratio) in two different height level milking machines. In two short experiments, testing different combinations of the parameters mentioned, milk fractioning, milking efficiency, teat end status and animal welfare were analyzed. Results showed that the height of the milking machine pipes can have an influence on which parameters are most optimal for milking efficiency and animal welfare in the milking of Murciano-Granadina goats.

Abstract

The Murciano-Granadina goat breed has been described as a slow milking breed. As milking machine parameters can affect milk extraction in terms of yield and time employed, two experiments of one-month duration were performed with 88 goats in Latin square design to find the best combination of these parameters. One of them was carried out in a mid-line milking machine and one in a low-line milking machine. For each of them, two vacuum levels (36 and 40 kPa), two pulsation rates (90 and 120 cycles/min) and two pulsator ratios (50 and 60%) were used and milking efficiency, sanitary status of the mammary gland, milk cortisol, and teat end status were evaluated. Results showed that in milking machines installed in mid- and low-line, the use of 40 kPa system vacuum, 60% pulsator ratio and 90 or 120 cycles/min pulsation rate achieved optimum milking fractioning and efficiency. In the case of low-level milking machines, a similar combination with 36 kPa not only showed worse milking fractioning values, but also provided better values of teat end status and cortisol level.

Effect of the type of milking on mammary gland examination in Saanen goats

ABSTRACT This research evaluated the effect of milking on the physical exam of the mammary gland (MG) and milk examination in Saanen goats. Six properties were selected, four farms were used after evaluation of criteria selection and distributed in two groups according to the milking method: manual or mechanical. The physical examination of MG was performed using the techniques of inspection and palpation, in addition to the examination of the milk by strip cup, California Mastitis Test, somatic cell count, and bacteriological exam. It was possible to detect an association between the milking method with the most of physical exam of the MG: inspection of the MG (p = 0.001), inspection of the teat (p = 0.002), palpation of the MG (p = 0.054) and palpation of the teat (p = 0.036). The machine milking had an association with the reduction of the volume of MG (OR = 6.00), reduction of the teat size (OR = 16.19), and firm consistency of mammary parenchyma (OR = 2.39). The use of machine milking represented a less risk for an increase of the volume of the MG volume (OR = 0.288) and the presence of cisternitis (OR = 0.490). The association between the SCC and the type of milking was also detected (p = 0.002). Machine milking was associated with changesin the physical exam of MG and milk examination compatible with traumatic lesions. This information indicates inappropriate use of milking equipment in the dairy goat’s properties.

Machine milking parameters for Murciano-Granadina breed goats

In dairy ruminants, the combination of milking parameters must ensure good milking performance without harming udder conditions. Commonly, milking conditions for goats are established without having checked the admissible limits for optimal and fast milking. The aim of this study was to establish a limit combination of machine milking parameters that improves machine milking performance without altering milkability or udder status. To this end, we studied the effect of 2 combinations (42 kPa, 120 cpm, 60% vs. 44 kPa, 120 cpm, 60% in terms of kilopascals of vacuum level, cycles per minute of pulsator rate, and percentage of pulsator ratio, respectively) on milk production and composition, milk fractioning during milking, SCC, teat tissue thickness variation after milking, and the milk emission kinetics parameters throughout 1 lactation period (6 mo). The 42 and 44 kPa measured at the vacuum gauge level became average values of 37.5 and 39.3 kPa, respectively, measured at the teat sphincter level during milking. Milk flow significantly increased and total milking time decreased 25 s with the elevation of the vacuum level from 42 to 44 kPa without any adverse effect on milk fractioning at milking. However, the use of 44 kPa also showed an increase in tissue thickness above 5%, and we observed a tendency of average conductivity of milk to increase, although without any adverse effect on SCC. It seems that 44 kPa, 120 cpm, 60% is a possible limit combination of parameters to improve milking performance without altering milkability or udder conditions. We concluded that this combination can be used for milking Murciano-Granadina breed goats in conditions similar to those of this study (mid-level milking system and 1 milking/d), although further studies are necessary to verify its application in the case of 2 milkings/d.

How does the milk removal method affect teat tissue and teat recovery in dairy ewes?

The aim of this work was to study how machine milking (MM) carried out in suitable conditions affects teat wall thickness and teat canal length and their return after milking to pre-milking conditions, in comparison with other milk extraction methods considered biological referents: lamb suckling (LS), milk removal by catheter (RC) and hand milking (HM). Three Latin square experiments were designed, using 11 ewes in the first experiment (LS), 13 in the second (RC) and 12 in the third (HM). Each of the Latin squares was divided into two periods: in the first, the left gland of each animal was machine milked and the corresponding treatment (LS, RC and HM) was applied to the right gland. Subsequently, in the second period the extraction methods were interchanged. During the experimental period, 4 sampling days were carried out (2 in each experimental period), where ultrasound scans were taken before (B) and immediately after milking (A) and at 1 (1 h), 2 (2 h), 3 (3 h), 4 (4 h), 6 (6 h), 8 (8 h) and 10 (10 h) hours after milking finished. Teat wall thickness (TWT), teat wall area (TWA), teat end area (TEWA) and teat canal length (TCL) were measured in all the ultrasound images. MM increased TWT after milking compared with RC. TWT, TWA, TEWA and TCL were lower (P<0.05) in HM than in MM. No significant differences (P>0.05) were found between LS and MM for any variable. The extraction method affected the recovery time of the variables, with total teat recovery at 6 h after RC and 4 h after HM. In the case of LS, the TEWA and TCL values were recovered sooner, as of 3 h. Teat recovery time after MM was similar to the extraction method with which it was compared in each experiment. Thus, considering the similar increase in wall thickness and their recovery time compared with the reference methods, it was concluded that machine milking, carried out in optimum conditions and respecting the time interval between milkings usually applied on sheep farms (8-12 h), would not affect teat integrity. Moreover, given the variability observed in teat thickness recovery time between the different experiments, further research should be carried out to study which factors intrinsic and extrinsic to the animal may affect the teat wall thickness and recovery time after machine milking.