Impact of lameness on the milk production of ewes 1

1Baranovič, Štefan–1,2Tančin, Vladimír–2Uhrinčať, Michal–2Mačuhová, Lucia–3Palkovič, Jozef 1Department of Veterinary Sciences, Faculty of Agrobiology and Food Resources, Slovak University of Agriculture, Nitra, Slovakia 2Animal Production Research Centre Nitra, Lužianky, Slovakia 3Department of Statistics and Operations Research, Faculty of Economics and Management, Slovak University of Agriculture, Nitra, Slovakia xbaranovic@is.uniag.sk


INTRODUCTION
Lameness is very serious disease that causes significant financial losses in dairy sheep (Green et al. 2012).Lameness causes less milk yield (Gelasakis et al. 2015) and terrible with welfare (Gougoulis 2010).Impact of lameness was detected also on bodyweight and lamb growth rates and wool growth (Stewart et al. 1984, Marshall et al. 1991).
The reason of lameness is pain that is created the by stimulation of nerve cells (Ley et al. 1995), as a result of various changes to the limbs (mostly on the hooves).Causes of lameness can be broadly classified as genetic, physical injury and infection (Coulon et al. 1996, Warnick et al. 2001, Green et al. 2002, Winter 2004).But lameness can persist also after healing disorders or diseases (Ley et al. 1995).
Impact of lameness on the milk yield was found out (Gelasakis et al. 2010(Gelasakis et al. , 2015) ) but precise information about the losses of milk lame ewes are not known because there are few studies that focus on changes in milk production as a consequence of lameness of ewes.
The aim of this study was assessing the impact of lameness on the milk production, somatic cells count and component of milk.We assess also impact of lameness on the order of entry into the milking parlour.

MATERIAL AND METHODS
The experiment was carried out at the farm, located in northern Slovakia.The farm keeps sheep Improved Valachian.Sheep were housed on deep litter and they grazed on adjacent pastures during the day.The main components of feed were pasturage (ad libitum) and feed concentrate (200 g per animal per day).Milking was performed two times a day in milking parlor 1×24.
Samples of milk were taken during two periods: May, July.In May, it was taken samples from random sampling ewes with milk yield minimum 300 ml per milking.It was taken 214 samples together.In July milk samples, milk yield and lameness from the same ewes as in May were recorded (project: Kega 006SPU-4/2014).We recorded also the order of entry into the milking parlour in milking row.Number of milking rows was recorded 23 together.
We evaluated the milk yield per milking (kg), fat (%), protein (%), lactose (%), the ratio of fat: protein (F/P), logarithm from somatic cell count (logxSCC ml -1 ) and changes in the milk yield and composition of milk that occurred between May and July.Analysis of milk samples for somatic cell count and essential components has been performed in National Agricultural and Food Center in Lužianky.
We recorded all lameness sheep in entering the milking parlour.Subsequently, we recorded the sheep those lifted (lighten) their limbs during milking.These sheep were marked as "strong lame" sheep.Sheep that lamed in entering the milking parlour but did not lift their limbs during milking were marked as "slightly lame".Sheep that neither did lame in entering the milking parlour nor did lift their limbs during milking were marked as "non-lame".
The results were mathematically processed using the Microsoft Excel program and statistically evaluated by SAS.

RESULTS AND DISCUSSION
It was evaluated 214 sheep with an average milk yield of 558±173 ml milk per milking, a fat content 5.83±0.96%,a protein content 5.90±0.50%and a lactose content 5.17±0.20% in May.The average value of the somatic cells count was 5.49±0.473(logx in ml).For July the milk yield was 349±143 ml milk per milking, a fat content 8.88±1.02%, a protein content of 6.47±0.52%and a lactose content 4.86±0.19%.The average value of the somatic cells count was 4.81± 0.628 (logx in ml).We found significant statistical differences between months (P<0.0001) in all the above mentioned indicators.These differences were mainly influenced by the stage of lactation.The decline of logxSCC between months is interesting because it may indicate the health of the udder was better in later lactation than at the beginning of lactation.
In July we recorded 26 ewes with slightly lameness and 18 ewes with strong lameness.Other ewes were non-lame.Non-lame sheep had in July the highest milk yield (356±148 ml) (Figure 1) and the lowest decrease in milk yield from May to July (-206±131 ml) compared with slightly (317±116 ml, -223±163 ml) and strong (319±122 ml, -219±151 ml) lame ewes.However, these differences were not statistically significant.
Lower milk yield for the lame sheep found out by Gelasakis et al. (2010).In the following study Gelasakis et al. (2015) proved the most significant difference in milk yield per milking between lame and non-lame sheep in the 8 th week of milking.In our study ewes were milked longer time as 8 weeks and it may affect the non significant differences in milk yield.Also sometimes it is difficult to prove lower production lame animals if their production compared with the average production animals that is non-lame because lameness is often hit the most productive animals which reduce production "only" on the average of the flock (Archer et al. 2010).We have not identified statistically significant differences between groups in somatic cell count (logxSCC for non-lame: 4.83±0.608 in ml, slightly lame: 4.76±0.653 in ml, strong lame 4.71±0.787 in ml).The effect of lameness on SCC was found out in herds of cows (Hultgren et al. 2004, Archer et al. 2011).Also our results show some tendency therefore we can expect statistically significant differences in a greater file of animals.
Milk composition (fat, proteins, lactose) nor changes in the composition of milk that occurred between May and July were not affected by lameness of ewes (Table 1).Lameness in July affected the change the order of entry of ewes in the milking parlour in July compared with the order of entry recorded in May.There was only a negligible decrease in the order of entry into the parlour in group non-lame sheep (-1.14 milking rows).But lameness sheep in July, entered into the parlour later than in May.Decrease was by group slightly lame -2.87 milking rows and by group strong lame even up to -4.19 milking rows.Statistically significant differences found out between groups strong lame and non-lame sheep (P<0.05).

CONCLUSIONS
While information about the impact of lameness on milk production in cows is quite a lot, it was realized few studies in sheep.Our study indicates relationship between lameness and milk production in ewes.We found out some impact between lameness and milk yield while milk components and somatic cells count were not affected.Also impact of lameness on the order of ewe's entry into milking parlour was significant.The further study could be focused to verification impact of lameness on the milk production during all lactation.

Figure 1 :
Figure 1: Dependence the milk yield per milking from lameness in July