Evaluation of sheep genetic resources in North America: Milk production and composition of purebred, crossbred and synthetic populations

Abstract

Evaluation of sheep genetic resources in North America: Milk production and composition of purebred, crossbred and synthetic populations. Can. J. Anim. Sci. 88: 569Á576. Purebreds, crossbreds and synthetic populations of sheep in North America of divergent genetic types produced 47Á103 litres of milk for 121Á144 d, consistent with ''non dairy-type'' breeds; however, this was substantially less than the 200Á330 kg of milk per lactation characteristic of ''dairy'' type breeds in Europe and the Middle East countries. Among established breeds, the Suffolk (Su) breed produced significantly more total and daily milk yield, respectively, for a longer lactation (79 litres and 589 mL for 139 d), followed by the Rambouillet (Ra), Targhee (T) and Dorset (D) breeds (60Á62 litres and 422Á542 mL for 120Á132 d), while the Lincoln (L) breed produced significantly less (48 litres and 285 mL for 128 d). Among fecund-type breeds and their crosses, Finnsheep (F) and Romanov (Ro) breeds produced significantly less (50Á55 litres and 425Á463 mL, for 122Á129 d), while Ro )F produced significantly more milk (91 litres and 744 mL for 126 d), followed by F )Ro (60 litres and 505 mL for 128 d). Among other crossbreds, F)Ra produced significantly more milk (66 litres and 434 mL for America exhibited diversity that was substantial for milk yield, but negligible for lactation length, as well as fat, protein, lactose and solid-not-fat content. Lack of inherent potential for milk production continues to be a serious constraint towards development of commercial dairy sheep industry. In the absence of ''dairy-type'' breeds, superior milk production in the Rideau Arcott breed (with East Friesian lineage) and their crosses demonstrates considerable promise for further improvement, thus increasing the efficiency of sheep production.

Experimental evaluation of milk yield and selected traits of milk quality in Clun Forest ewes

“…a-c The same characters on one line indicate the statistically significant difference between individual samples (tested by paired Student's t-test) P < 0.05A-D The same characters on one line indicate the statistically significant difference between individual samples (tested by paired Student's t-test) P < 0.01 https://doi.org/10.17221/221/2022-CJAS evaluated byBendelja et al (2009);Mioc et al (2009) andOravcova et al (2018). Regarding the comparison with non-dairy breeds, in our experiment, the average DMY for the whole lactation period in CF was higher or comparable with the values found for this trait bySakul and Boylan (1992) in Dorset, Lincoln, Rambouillet, Romanov and Suffolk ewes;Nudda et al (2002) in Merino ewes;Shrestha et al (2008) in Lincoln, Targhee, Dorset, Finnsheep, Romanov and Suffolk ewes andKremer et al (2010) in Corriedale ewes. On the other hand, the average DMY of CF ewes for the whole lactation was lower than reported bySlen et al (1963) in Suffolk, Hampshire, Rambouillet, Canadian Corriedale and Rommelet ewes;Ochoa-Cordero et al (2002) in Rambouillet ewes andMorgan et al (2006) in Border Leicester and Coopworth ewes.…”

“…The assessment of milk production in non-dairy sheep is generally infrequent. However, studies carried out by Sakul and Boylan (1992), Peeters et al (1992), Ochoa-Cordero et al (2002), Morgan et al (2006), Shrestha et al (2008), Kremer et al (2010) and Milerski et al (2020) were primarily focused on this issue. These studies mainly show that in non-dairy ewes, the milk yield is usually lower, and the length of lactation is shorter than that of traditional dairy ewes, but the contents of protein and fat in milk are comparable.…”

Milk production and body composition of single-bearing East Friesian×Romney and Border Leicester×Merino ewes

“…Others have found that EF have a higher or more sustained milk yield than traditional meat or wool breeds. For example, Shrestha et al (2008) presented collated data for milk yield of non-dairy (60-90 kg per lactation) and dairy breeds (200 -330 kg per lactation) of sheep that indicated that milk yield was substantially higher in the latter, which included the Awassi and EF breeds among others. Consequently, over the past 30 years, the EF breed has been introduced to a number of countries to improve milk production of the local sheep breeds and for lamb meat production, generally as a F1 crossbred, due to their high twinning and growth rate (Boyazoglu, 1980;Allison, 1995;Ugarte et al, 2001).…”