Pregnancy‐Associated Glycoprotein (PAG) Profile of Holstein–Friesian Cows as Compared to Dual‐Purpose and Beef Cows

Abstract

Pregnancy-associated glycoproteins (PAGs) are produced by mono- and binucleate trophoblast cells in the ruminant placenta. PAG appears in maternal blood and, from approximately 4 weeks after fertilization onward, may serve as a reliable means of diagnosing pregnancy. A range of factors are said to affect plasma PAG concentrations, such as number and sex of foetus, mass of calf and placenta, level of milk production and genetic constitution. In this study, PAG pregnancy profiles of a dual-purpose (Simmental) and two beef breeds (Uckermark and Aubrac) are compared with the profile of the specialized dairy breed Holstein-Friesian. Holstein-Friesian cows were sampled weekly; the levels of the other breeds were presented at 3-week intervals. The overall significant breed difference (p = 0.013) was founded on deviations during the initial 3 weeks of pregnancy and from 23 weeks onward. During the period critical for the detection of pregnancy, between four and 22 weeks, agreement between PAG levels of various breeds was close (p > 0.05). No significant effect of body mass of cow or calf (relative to mass of dam) was detected. These findings imply that the PAG pregnancy test may be executed uniformly irrespective of breed or type of cow, affirming the suitability of the test as a valuable asset for the cattle industry.

Application of an ELISA Milk Pregnancy Test in Beef Cows

“…) and that serum PAG levels in Simmental breed of beef cattle are comparable to those in Holstein‐Friesian cattle (Shahin et al. ). The current study is the first report evaluating the relationship of milk and serum PAG in beef cows.…”

“…; Friedrich and Holtz ) and continue to increase throughout pregnancy until parturition (Friedrich and Holtz ; Shahin et al. ). The use of a serum‐based PAG ELISA for pregnancy diagnosis in cattle has been determined to be most accurate after 28 days following insemination (Green et al.…”

“…Although the milk PAG ELISA has primarily been developed as a management tool for dairies, it may also have potential in the beef industry as it has been shown that serum PAG profiles in beef cattle closely resemble those of dairy cows (Shahin et al. ).…”

“…PAG enter maternal circulation following placental attachment and fusion of the binucleate cells with the uterine epithelium (Green et al 2005;Piechotta et al 2011). In cattle, PAG have been detected in serum as early as 22 days postinsemination (Zoli et al 1992;Friedrich and Holtz 2010) and continue to increase throughout pregnancy until parturition (Friedrich and Holtz 2010;Shahin et al 2014). The use of a serum-based PAG ELISA for pregnancy diagnosis in cattle has been determined to be most accurate after 28 days following insemination (Green et al 2005).…”

“…In addition to their presence in maternal serum, PAG cross the blood-milk barrier in the mammary gland of the dam via passive transport and are detectable using a commercially available ELISA recently developed for use in dairy cattle (Friedrich and Holtz 2010;LeBlanc 2013;Lawson et al 2014). Although the milk PAG ELISA has primarily been developed as a management tool for dairies, it may also have potential in the beef industry as it has been shown that serum PAG profiles in beef cattle closely resemble those of dairy cows (Shahin et al 2014).…”