Haemoglobin types and the geeldikkop‐enzootic icterus disease complex in sheep

Genomic Tools for the Identification of Loci Associated with Facial Eczema in New Zealand Sheep

“…In agreement with this study, and the Norwegian studies, Hb-A was shown to have a functional advantage in sheep affected by geeldikkop; both Hb-A and Hb-AB lambs were more resistant to serious haemolytic episodes, and a more severe temporary liver insufficiency developed in Hb-B animals than Hb-AB types [74]. Haemoglobin C (Hb-C) was present in Merino sheep recovering from a geeldikkop attack but was not present in the animals before the onset of the disease, with the authors suggesting that it may aid in recovery from the disease [75]. Of additional interest is that the frequency of haplotype A was higher in South African farms that had large scale outbreaks of haemolytic syndromes in their recent history [75].…”

“…Haemoglobin C (Hb-C) was present in Merino sheep recovering from a geeldikkop attack but was not present in the animals before the onset of the disease, with the authors suggesting that it may aid in recovery from the disease [75]. Of additional interest is that the frequency of haplotype A was higher in South African farms that had large scale outbreaks of haemolytic syndromes in their recent history [75]. Previous work looking at the distribution of haemoglobin in New Zealand sheep has found both types present in both Romney and Finnish Landrace breeds, with the A haplotype at a frequency of 0.6 and 0.84 in each breed, respectively [76].…”

“…The A and B variants of sheep β -globin (Figure S2) were characterised by the following amino acid changes from A (UniProt ID: Q1KYZ7) → B (UniProt ID: P02075), respectively: S 59 → N, A 67 → P, VQ 75 → MK, S 119 → N, E 128 → D and R 143 → K. These amino acid changes are found in four tryptic peptides from haemoglobin β. In the A variant, these peptides are defined by the following residues: 40-58, 65-81, 116-131 and 132-143.…”